UWE

Evolution of Building Elements

Contents

1 Foundations

2 External walls

3 Ground Floors

4 Upper Floors

5 Roof structure

6 The Services of Victorian and Edwardian Houses 1850-1914

1 Foundations

Late 19th century

In 1875, the Public Health Act was introduced. It required urban authorities to make byelaws for new streets, to ensure structural stability of houses and prevent fires, and to provide for the drainage of buildings and the provision of air space around buildings. Three years later the Building Act of 1878 provided more detail with regard to house foundations and wall types. The Local Government Board, in its response, issued the first model bye-laws ('by' or 'bye' is old Danish and means local) for new streets and buildings as a guide for urban authorities making their own byelaws.

The bye-laws made under the Act of 1878 required concrete (9" thick - 225mm) to be placed under the footings unless the sub-soil be gravel.  It is not clear how many local authorities adopted these bye-laws outside London. The London County Council was created in 1889, and sponsored the London Building Act of 1894 which amended the rules relating to foundations and the thickness of external and party walls. This seems like a backward step - they no longer specify concrete footings, instead preferring brick ones. A writer at the time noted, "the bye-law on the whole is a wise one, as concrete is so easily scamped, but there are many cases in which concrete alone would be more economical and more stable".

Part of the requirements for external walls and footings is shown below. By today's standards the foundations seem very shallow; in fact many text books from the time suggest that foundations should never be less than 12 inches (300mm) deep and often much more.  

Text books of the time suggested that Portland cement made the best concrete although hydraulic lime was the next best thing. Common lime (hydrated lime) was seen as a much inferior product. A mix of approximately of 1:1:4 or 1:1.5:5 was recommended, cement:sand:stone.

Many local authorities were slow in adopting Model Bye-laws; even where they did, building control was fairly lax. This meant that the nature and quality of foundations varied considerably. The graphics below show typical foundations at the end of the 1800s. The depths varied according to circumstances but generally they were shallower than their modern counterparts.

 

The drawing below dates from 1903 and shows a section through a planned house. The foundations look quite shallow. Whether or not this was just a drawing convention of the time we do not know; presumably the depth of the actual foundation would depend on specific circumstances.  

 

Reinforced foundations were not unknown. G Lister Sutcliffe states, "..frequently the metal is in the form of steel rails....or twisted wires...  embedded in the concrete.  A stronger foundation can be obtained in less depth than when concrete alone is used".

Between the Wars

During the 1920s and 30s foundations remained much the same. Text books from the 1930s suggest that in clay soils foundations should be 3 feet deep (900mm) - guidance in fact not much different from today.  London Building Acts and Model Bye-laws introduced a number of minor amendments (see below). The examples below were suitable for houses with foundations in firm clay or coarse sand.

Note that the 1939 bye-laws still permitted brick footings and also mentioned the option of rafts and piles.

Post 1945

In the late 1940s and throughout the 1950s most new houses were built with strip foundations. Raft foundations were also popular, particularly under system-built properties or over areas of fill. A typical raft comprised a concrete slab 6" to 9" thick (150mm to 225mm), suitably reinforced. A few foundations were piled - short bored piling systems became common during the early 1960s. The piles were typically 6' to 12' long (1.8 to 3.6m), not normally reinforced but with a reinforced ground beam over the top, cast on some form of compressible material (ash or clinker).      

The Model Bylaws were replaced by National Building Regulations in 1965. These Regulations were applied generally throughout England and Wales, with the exception of the Inner London Boroughs (the area of the former London County Council) where the London Building Acts continued to prevail. Various amendments and revisions to these Building Regulations were issued increasing the scope and areas covered by Building Regulations. This continued until the Building Act 1984 finally consolidated Building Regulations under one piece of legislation. This resulted in the introduction of the Building Regulations 1985 that came into operation in November 1985.

The Building Regulations contain 'deemed to satisfy' provisions for strip foundations. For modest loads and on certain types of ground acceptable strip foundation widths are given - see the Building Regulation section for the table itself.  Outside these boundaries, for example a 4 storey building on soft clay, the foundation has to be specifically designed.

Raft foundations and piled foundations do not have any 'deemed to satisfy provisions' and always need to be designed.  Today, rafts are comparatively rare except in former mining areas. Piling has become very common for four main reasons; it's much cheaper than it used to be, smaller, lighter piling rigs are now available, shoring traditional trenches is expensive, and brownfield sites are often not suitable for strip foundations.

 

 

There is much more information on piling in the Foundations section of this web site.

2 External walls

Early Brickwork

During the 1700s there were a number of improvements in brick making. Blended clays, better moulding techniques and more even firing gave greater consistency in brick shape and size. Fashion dictated brick colour: the reds and purples popular in the late 1600s gave way to softer brown colours in the 1730s. By 1800 the production of yellow London stocks provided a brick colour not that much different from natural stone. The repeal of the brick tax in 1850 gave the brick industry a new impetus. Improved mixing and moulding machines, together with better firing techniques, allowed brick production to reach new heights. Bricks were now available in a range of colours, shapes and strengths that would have been unimaginable a 100 years earlier. Better quarrying techniques allowed extraction of the deeper clays which produce very strong, dense bricks; vital for civil engineering works such as canals, viaducts sewers and bridges.

Brick bonding

By the end of the 19th century most houses had walls of at least one-brick thickness. Houses over three storeys often had thicker walls, usually reducing in thickness at each upper-floor level. The brickwork itself (at least the brickwork on view) was generally laid to a very high standard. Most houses were built in Flemish bond although rear walls or walls hidden by render were often laid in Garden wall bond (usually English).

Stonework

Stone was often used for prestigious buildings or in areas where it naturally occurred. In upland areas (the north and west) stone was often the obvious choice for building because it was readily available (and prior to the railways these were often areas where bricks were expensive). There are 3 groups of stone; igneous, sedimentary and metamorphic. The sedimentary group, which includes limestone and sandstone, accounts for most of the stone used for building in the UK.

Rubble walling is found in a variety of styles. At its cheapest it comprises rough stonework, built as two outer leaves and bound together with copious amounts of lime mortar. More expensive work comprised squared rubble possibly set against a brick backing. In most situations a stone wall has to be thicker than a brick one. So, whereas a 1 brick thick wall (215mm or so) might be fine for a two or three storey house, a stone wall is likely to be 325mm or even more. Most rubble walls were pointed flush or slightly recessed. The ribbon pointing so often seen nowadays is not traditional, neither is it particularly durable.

Stonework which is dressed and/or finely cut is often referred to as dimensioned stone. Sometimes it's referred to as freestone. This means it can be worked (cut, shaped and smoothed) with a chisel and a saw in any direction. It has a fine grain and is free from obvious laminations and pronounced bedding planes. In the 18th century whole cities were built (some rebuilt) in stone. It was not cost effective to build the whole of the wall in freestone and a backing material of rubble or brickwork can nearly always be found. In some houses only the front elevation would be built in freestone, the sides and back being constructed of rubble or brick. To bond the two halves of the wall together, 'through' or bonding stones were used.

Where the freestone is laid with very fine joints, almost invisible from more than few feet away, the work is knows as ashlar. In some parts of the country the stones were cut with a taper to make the joints easier to form. Wedges made from bits of timber or even oyster shells were often pushed into the back to provide stability as the mortar set. These buildings were built with lime mortar which hardened very slowly. Hydraulic limes were not unknown but they were less common and more expensive. In addition they often set too quickly resulting in high waste on site. 


Mortar

Lime mortars were common until the 1930s, in some parts of the UK, even later. Limestone or chalk was burnt with coal to form Quicklime. The burnt lime is known as lump lime. The Quicklime was then slaked with water and then mixed with fine aggregates (nowadays sand) to form mortar. It could take many months for a lime plaster to fully set. Then process is known as carbonation. Some limes have a hydraulic set (a bit like a weak cement). This could be induced by adding pozzolans which contain silica. Another option was to use a lime which naturally contains silicas (usually a proportion of clay). A hydraulic 'set' is quicker and stronger than carbonation. Some of the very strong hydraulic limes are not dissimilar to modern cement; made of course, from chalk and clay.

During the 1930s and 1940s cement mortars gradually replaced lime ones. Lime was often added to the mix to improve its working and qualities and durability. More detail can be found lower down the page. 
 

Pointing

In the early 1900s period joints were usually finished flush or slightly recessed.  Where very good quality bricks were used the joints were often only 8mm, or even less. This, together with the use of brick dust in the mortar, meant that the mortar had very little affect on a building’s appearance.  Working-class housing was usually pointed in a lime mortar which included local industrial waste products as fine aggregate. Perhaps ash was the most common. The photos below show three examples of good quality 19th century brickwork.

Tuck pointing was usually reserved for the best quality work. Tuck pointing is basically in two parts, a bedding mortar often containing aggregates to match the colour of the bricks or stonework, and a thin ribbon of lime pointing to finish the joint. From a distance a wall that is tuck pointed appears to be finely jointed.  Examples of tuck pointing can be found under the Walls section of this web site.

Cavity walls

In the latter part of the 19th century a number of houses were built with cavity walls. It was not, however, until the 1920s that this became the accepted form of construction. Cavity walls were cheaper to build than their solid wall counterparts. In addition they offer improved thermal insulation and better weather protection. Most walls comprised two half-brick leaves with a 50mm cavity. The two halves of the wall were tied at regular intervals with steel or wrought iron wall ties. The external leaf of brickwork was laid in facing bricks, the internal leaf in commons. A few early cavity walls had an external leaf one brick thick and, in some early forms of construction, the DPC ran right across the cavity.



 

DPCs (to prevent rising damp) were in common use by the early 1900s. They could be made from lead, pitch, asphalt and slate. Not until the mid 1920s did vertical DPCs become a standard detail around openings.  

1930s to 1960s

During this period cavity walls changed little. Mortars gradually became cement-based rather than lime-based because the faster setting mortar meant faster construction. Blockwork became a common material for the inner leaf of cavity walls - the blocks were usually made with an aggregate of stone or industrial waste (clinker and breeze were common). A few houses, usually Modernist-style houses with a rendered finish, were built with walls of solid blockwork (ie non cavity).   

Note that during the 1950s and early 1960s several thousand houses were built in non-traditional construction. These were often constructed using precast frames or panels; in some cases insitu panels. Some systems were based on timber. For more information go to the System Building section of the web site.   

1970s to 1980s

In the 1970s insulation standards slowly improved. A maximum 'U' value of 1.70 was introduced in 1972 (a measure of a the wall’s ability to transmit heat - explained further in the Walls section). Achieving this standard was relatively easy; a brick external leaf, a 50mm cavity, and a dense block inner leaf finished with 13mm lightweight plaster, just made the 1.7 threshold. In 1980 the maximum U value dropped to 1; this required lightweight blockwork in the inner leaf. From this period to the present day most lightweight blocks have been made from aerated concrete. They were (and still are) made from cement, lime, sand, pulverised fuel ash and aluminium powder.  Once these materials are mixed with hot water the aluminium powder reacts with the lime to form millions of tiny pockets of hydrogen.  However, there are several other materials for blockwork which have enjoyed brief popularity. These include concrete blocks faced with insulation, hollow blocks containing polystyrene granules and blocks made from pumice or no-fines concrete.

Modern cavity walls

In the 1990s the maximum U value dropped to 0.45; this normally required a very thick lightweight inner leaf or cavity insulation.  There are three common options, most of which require lightweight or aerated blocks in the inner leaf. These are:

It is still possible to build solid walls - but this is impractical using brick. Only aerated concrete will give acceptable levels of insulation.

 



 

At the time of writing (2006), U values have to less than 0.3 so a modern cavity wall has a ‘U’ value some 5 or 6 times better than its 1920s counterpart. In the above examples slightly thicker insulation will give a U value of 0.30. In modern construction cavity widths have increased well beyond the 50mm common 80 years ago. A 50mm clear gap is required if board insulation is used. This commonly requires a cavity 90mm wide.

Wall Ties

Wall ties are now mostly stainless steel. There are various patterns; the washer shown below is to hold insulation boards in position against the inner leaf. These particular ties are all made by Ancon.

Modern mortars

Modern mortars are made from cement and sand. Hydrated lime (ie bagged lime) is often introduced into the mix to give it a more plastic feel and to make it more ‘workable’.  Lime also improves the mortar’s ability to cope with thermal and moisture movement. In recent years the use of pre-mixed mortars has become common. These are delivered to site in sealed containers, ready for use. They usually contain a retarder so they remain usable for 36 - 48 hours or so. At the end of this period they develop their strength in the same way as normal mortars.

The face of the joint may be finished in a number of ways – the three most common are shown below.  Tooled joints (where the mortar is pressed against the brickwork) offer the best weather protection because the tooling smoothes and compresses the joint.

This is a copy of an older 'hand out' on evolution - you may find it useful. The images are pre-publication proofs from 'House Inspector'.

3 Ground Floors

Early Timber Floors

Most houses at the end of the Victorian period (1900) were built with suspended ground floors.  There were exceptions to this. Many houses had ground floors constructed with stone or clay flags; basements too were covered with flags.  These were laid on a bed of ashes or directly onto compacted earth. Houses without basements usually had a scullery at the back of the house, often in a rear extension. Most sculleries had solid floors - they were used for washing and were likely to stay wet for long periods. The scullery floor was often 6 inches or so (150mm) below the main house floor in case of leaks or flooding. Some of these solid floors were made from concrete.

A typical suspended timber floor from about 1900 comprises a series of joists supported by external and internal loadbearing walls and covered with floorboards.  Deep joists were expensive (they still are) and to reduce joist size there were usually intermediate supports known as sleeper walls.   These are small walls in rough stone or brickwork built directly on the ground or on small foundations.  In practice, ground-floor joists are often half the depth of those used in upper floors where, of course, such intermediate support is not possible.

The joists are typically 100mm x 50mm and are usually at 400mm centres or so (16inches). To ventilate the sub-floor void terra cotta or cast iron air bricks were built-in to the external walls. In practice ventilation was not always effective, partly because there were not enough vents and partly because these houses were terraced. This meant that there were only two external walls. In addition, the sleeper walls were not always honeycombed (ie with ventilation gaps); this impeded cross ventilation.  

Towards end of the Victorian period DPCs, often formed in brittle materials such as slate, were becoming common (but by no means universal). These helped protect the joist ends from rising damp. 

In practice such floors often give rise to expensive maintenance problems due to poor design and varying standards of workmanship. They were generally badly ventilated, often prone to flooding (the ground level under the floor was often lower than the ground outside), and the joist ends are always at risk because they are normally only protected by a half-brick thickness of wall.

Some houses had concrete floors in the hallways, or maybe just in the lobby by the front door. These were usually covered with decorative tiles laid in mortar on a concrete slab (left).

 

 

 

The 1920s

During the first 20 years of the century suspended timber floors changed. A number of improvements were introduced, mostly damp related. In the graphic below note that the entire floor is separated from the substructure by the DPCs. In addition, the bare earth is covered with a concrete slab (often referred to as an ‘oversite’) which is at, or above, external ground level to prevent the build up of water.  The slab also prevents growth of vegetation. The floor joists are supported by honeycombed sleeper walls, through which air can pass easily, and the joists do not touch the external wall. Because most of these houses were detached or semi-detached, rather than terraced, the underfloor void is relatively easy to ventilate.

Ground bearing concrete floors - 1950s

Concrete ground floors were not unknown in the 1930s but they became more common in the 1950s because of the post War restrictions on imported timber (restrictions lasted for nearly 10 years). The floor is basically a bed of concrete, supported by the ground directly beneath it, and quite independent of the surrounding walls. 

A typical floor from the 1950s might comprise a layer of hardcore (stone or broken brick), a concrete slab probably 100 to 125mm thick and the floor finish. This is often timber to disguise the nature of the floor, or, in cheaper construction, thermoplastic tiles laid in bitumen adhesive. Some floors, by no means all, contained damp proof membranes, usually liquid based.

In many houses the only barrier to rising damp was the bitumen bedding material under the wood blocks or thermoplastic tiles. Thermoplastic tiles were first produced in the UK just after the Second World War. The tiles were made from a mixture of resin binders, mineral fillers, asbestos and pigments. Most were 9 inches square (225mm). Early tiles were quite brittle. Asbestos vinyl tiles were introduced in the mid 1950s; they were made in much the same way but they were more flexible.  

 

Ground bearing concrete floors - 1960s to 1990s

From the mid 1960s to the mid 1990s a typical concrete floor comprised a layer of hardcore, a polythene damp proof membrane laid on a thin bed of sand (to prevent puncturing), and a floor screed.

 

Hardcores varied in quality - many have since proved to be totally unsuitable. In the mid 1960s polythene damp proof membranes were introduced and became an accepted form of damp proofing.  This barrier was usually laid below the concrete slab. DPMs on top of the slab, ie sandwiched under the screed, were also common and usually in liquid form, eg hot bitumen, or cold bitumen in solution.  Liquid DPMs gave the best protection but were more expensive. The concrete slab was usually 100 to 125mm thick. In certain situations, ie where the ground was uneven or where there were soft spots below the slab, it might be reinforced with a mesh.

The floor screed provided a smooth finish suitable for carpets or tiling. It was laid towards the completion of the building prior to hanging the doors and fixing the skirtings.  It was (and is) is a mixture of cement and course sand (typically one part cement to three or four parts sand) mixed with the minimum amount of water and laid to a thickness of 38-50mm. A few floors had a DPM formed in 20mm asphalt. This could be trowelled to a level finish and precluded the need for a separate screed.

Modern Concrete floors

Since the mid 1990s the Building Regulations have required insulation in ground floors.  A variety of manufacturers produce a range of rigid insulation boards which can be laid above or below the slab. Some of the boards have a closed-cell structure and are impervious to both water and vapour.  They can therefore be laid under the DPM (the DPM is still necessary to prevent moisture rising between the board joints and penetrating the slab).  Where boards are laid under the DPM blinding is not always necessary. Typical construction is shown below.

Chipboard flooring

In modern construction chipboard floating floors have become a common alternative to a sand/cement screed. Chipboard and strand board are both very sensitive to moisture and a vapour control layer is normally required under the boarding to prevent drying construction water (ie in the concrete) affecting the floor. This membrane is in addition to the DPM below the slab. The tongued & grooved boarding has glued joints and normally sits on a resilient layer of insulation; a perimeter gap of 10mm or so allows for moisture and thermal expansion. This gap is covered by the skirting.

 

Suspended concrete floors

In certain conditions the use of a ground bearing slab is not suitable. In these situations it is common to find a suspended concrete floor.  In fact, nowadays, many developers prefer to use suspended concrete floors in all situations because of the perceived risks of ground bearing floors. Until the 1970s these floors were often constructed from insitu concrete but they were slow to construct and very expensive. Nowadays, the floors are usually made from a series of inverted ‘T’ beams, 150-200mm thick, with a concrete block infill. The two most popular finishes are screed or particle board, both laid on insulation. 

Nowadays the Building regulations require that the underfloor space is vented; before 2004 it was only necessary to ventilate the space if the ground was not well drained or if there was a risk of gas build-up. DPMs are not required as long as minimum recommended gaps between floor soffits and sub-soil are maintained.

Modern timber floors

In modern construction timber floors are, once again, becoming popular. The construction is similar to that of 70 years ago although there are a few differences:

This is a copy of an older 'hand out' on evolution - you may find it useful. It includes two pages on upper floors. The images are pre-publication proofs from 'House Inspector'.

4 Upper Floors

Introduction

The upper floor of a modern house is not that much different from its 1800 counterpart. In other words it comprises a series of timber joists (there are modern alternatives) covered with some form of floor boarding. Nowadays we always expect to find a ceiling although, 150 years ago, the joist soffit was often left open in working-class housing. In modern construction the size and spacing of the joists are subject to the Building Regulations. Before 1965 they were mostly controlled by Model Bye-Laws or accepted building practice.

Note that this brief introduction does not include the construction of floors between flats. Information on this can be found under the Floors section of this web site.

Late 19th century

At the end of the 19th century a typical well-built terraced house would have an upper floor constructed from 8" by 2" (200 x 50mm) softwood floor joists fixed at 12" to 16" centres (300 to 400)mm. The joists were usually built in to the walls although occasionally wrought iron or brick corbels were used. Corbels were expensive but did ensure that joists on party walls did not penetrate the brickwork (better sound and fire protection) and that joists on external walls were protected by the full thickness of the wall (less chance of rot).

The floor was normally covered with square-edged softwood boards and finished with a lath and plaster ceiling - usually 3 coats of lime plaster. The direction of the joists can either be party wall to party wall, or front to back. The joists were trimmed around fireplaces and stair openings as shown in the graphic.  A half-barrel vault supported the hearth. Note that more information on fireplace construction can be found in the Heating section of this web site.

 

Larger properties may have had double floors, in other words a floor with a primary timber (or steel) beam running at right angles to the joists and supporting them mid span. An advantage of a double floor is that it keeps the floor depth to a minimum and provides all four walls with lateral restraint. Larger, more prestigious, properties sometimes had various types of tongued and grooved boards rather than square edged ones. These are shown further down the page.

1930s

In the 1930s the construction was much the same. Contemporary text books show a number of alternative methods of supporting the joists to suit a Model Bye-law of the time which required that no timber could be built within a half brick of the centre of a party wall. The bye-law also specified that all joists should rest upon a wall plate or steel bearing bar (to spread the load across the wall). In practice these bye-laws were often not adopted by local authorities or just ignored.  Text books also suggested that joist ends should be tarred or creosoted where they were built into walls.

'Specification' from 1931 provides some general guidance on the construction of upper floors (interestingly enough it does not mention the bye-law requirements). Single floors were normally thought to be acceptable for floor spans up to 16 feet; above that double floors were recommended.

    

 

Herringbone strutting was normally recommend at 6 feet intervals (1.8 metres). Unlike Victorian and Edwardian floors the hearth support was often in the form of insitu concrete reinforced with mesh rather than a half barrel vault.

1950s and 1960s.

In the post War period timber imports were strictly controlled. Although some system-built houses had floors made from steel joists  most houses had fairly traditional upper floors, often with centres 'stretched' and joist sizes reduced, to save timber. In addition strutting was often omitted. Floor coverings were usually tongued and grooved softwood. Boarded ceilings replaced lath and plaster - fibre board, asbestos board and plasterboard (often small sheets - ie plasterboard lath) were all common. Joists were built-in or supported on hangers. 

By the 1960s timber rationing was over and floor timbers reverted to pre-War sizes. The 1965 Building Regulations introduced tables for sizing floor joists and these remain much the same to this day. During the 1960s plasterboard became virtually the only material used for ceilings. The boarding was normally 10mm or 12.5mm thick (3/8inch or 1/2inch) with an artex or gypsum plaster finish.

Modern Floors

The construction of modern upper floors is shown below. They differ from 1950s floors in three main ways: strapping is now required to restrain the external walls, joist hangers are almost obligatory (to prevent air leakage), and floor boards have largely been replaced by chipboard or strand board. Modern ceilings are still nearly always formed in plasterboard.  Nowadays plasterboard lath is rare; the construction usually consists of large sheets of 15mm plasterboard, screwed to joists or to resilient bars, and then taped and painted.

In recent years the use of metal web joists and ‘I’ joists has become more common. In principle these are no different from traditional ‘cut’ joists. One advantage is that they are capable of increased spans. The use of metal web joists also precludes the need for potentially damaging joist notching.

Flats

In flats the floors separate dwellings and, therefore, must provide good fire protection and resistance to the passage of impact and airborne sound. The methods of construction shown above are not suitable. Modern options and a brief historical overview can be found in the Floors section of this web site.   

 

5 Roof structure

Introduction

During the 19th century the construction of domestic roofs changed little. In the late 1800s timbers were cut by machine rather than by hand, and fixings in the forms of nails, screws and bolts were cheaper and more readily available, but the nature of the structure was much the same as it had been 100 years earlier.

1900s

A typical roof comprised a series of sloping timbers known as rafters fixed, at the top to a ridge board, and at the bottom to a wall plate. Ceiling joists supported the ceiling and acted as a tie to the rafters - to stop the rafter feet from spreading. A binder running at right angles to the ceiling joists could be added to help prevent deflection in the joists. In some houses the binder was connected to the ridge by a hanger, again to prevent deflection.

This type of construction could be adapted for larger roofs. The roof shown on the right is the same in principle although there is an additional timber known as a purlin which prevents the rafters from sagging mid span.   The purlin is supported by the gable-end walls (party walls in mid-terraced houses) and is sometimes strutted from an internal loadbearing wall (and sometimes the gable walls) to a provide additional support.

 

The feet of the rafters were designed to provide a roof overhang or to finish flush with the wall. A fascia board at the feet of the rafters finished off the roof and supported the cast iron or, in a few cases, timber guttering.

Some very large houses with big rooms did not have an internal loadbearing wall in an appropriate position. Other ways had to be found of supporting the purlins mid span. King and Queen post trusses could be used in this instance. These were also widely used in factories and warehouses where large uninterrupted spaces were required.

 

Nearly all the roofs built before 1940 would have been based on the closed couple or purlin design. Sometimes the style was adapted slightly. A hipped roof (below) is a different shape but the arrangement of the timbers is much the same. Larger examples had strutted purlins; larger examples still, had trusses - usually one full truss spanning front to back, and and a half truss supporting the end (hip) purlin.


 

Post War Years

During the War 500,000 homes were damaged or destroyed. In the post War period there was a massive building programme not just to rebuild these damaged homes but also to continue the slum clearance work of the 1930s. But, at the same time, there was a chronic (it lasted for nearly 10 years) shortage of materials. In an attempt to avoid economic disaster the government placed strict limits on the import of materials. Timber was in short supply and new techniques had to be found. At ground floor level timber was saved by building floors in concrete. This was not a practical solution for roofs (apart from a few flat roofs in system-built houses) so techniques were developed which would reduce the amount of timber used in a roof. The TRADA truss is basically a lightweight version of the trusses shown above. They did away with the need for internal loadbearing walls upstairs and allowed for smaller section rafters - often at slightly wider centres. They were common during the 1950s.


Trussed rafters

The TRADA truss was relatively short lived. Most modern roofs are constructed from trussed rafters; they have been popular since the 1960s. The most common pattern is the Fink or ‘W’ truss designed for symmetrical double-pitch roofs although there are a variety of shapes suitable for most roof designs.  The trussed rafters are prefabricated and delivered to site ready for lifting onto the supporting walls, although occasionally you will find the entire roof structure assembled on the ground and lifted into place by crane.

The timbers, which are typically 80 x 40mm in section, are butt-jointed and held together by special plates (first introduced to the UK in the mid 1960s) which are pressed into position by machine.  Nowadays the timber are normally pre-treated to guard against rot and insect attack.

 


Trussed rafters offer several advantages when compared to traditional roofing methods.

Perhaps their major disadvantage is that use of the roof space for storage (when using normal trusses) is severely limited due to the nature of the timbers. When the trusses are in position additional timbers (braces) need to be added to produce a strong, rigid roof structure. These are explained elsewhere on this web site. 

New 'cut' or traditional roofs are sometimes still found but they tend to be one-off dwellings often with living accommodation in the roof space.

Modern trussed rafters and traditional roofs are both supported on softwood wall plates bedded in mortar on the inner leaf of the cavity wall. It's normal practice to strap the roofs to the blockwork inner leaf to prevent them lifting or moving in high winds. Modern roofs are normally ventilated to help minimise condensation. This is usually done by installing air vents at the eaves. There are other methods and these are explained elsewhere on this web site.

This is a copy of an older 'hand out' on evolution - you may find it useful. The images are pre-publication proofs from 'House Inspector'.
 

6 The Services of Victorian and Edwardian Houses 1850-1914

The nineteenth century witnessed a massive expansion of Britain’s urban population. In just one decade, between 1841 and 1851, English towns grew by 25.9 % and at the mid point of the century, 54% of the population lived in urban accommodation. Between 1851 and 1911, the population doubled whilst the urban population increased three times: by 1911, 79% of the population lived in towns. This represented a massive challenge to the British building industry and over the sixty year period from 1850, with fluctuations over time and variations from one locality to another, large areas of suburban housing were created. Over a hundred years later many Victorian and Edwardian areas of housing remain an essential feature of the British townscape.

The new suburbs were sharply socially segregated with marked differences in the quality of the housing and the level of services provided by the developer. Working class housing was typically situated close to the places of work and consisted largely of rows of densely packed terraced houses. Individual houses were small – typically four or six rooms – although some were smaller. Overcrowding was common. The prosperous middle classes, on the other hand, sought to escape the smoke and smell of industry and the noise and dirt of humanity in new quiet residential areas. Large terraced houses, fashionable with the well to do in the first half of the century, fell from favour after 1850: instead, the preferred house type was the substantial detached or semi-detached villa with twelve rooms or more and sufficient space for servants to live and work separately from the family. Privacy and domestic comfort were of paramount importance to the Victorian middle class household. It was not only the plan of the middle class villa – large enough to ensure virtually complete segregation of servants from the family – but the level and quality of services which distinguished them from the cottage homes of the industrial suburbs. The period 1850-1914, nevertheless, saw vast improvements in the services provided at all social levels. These were the result of a combination of technical innovations, rising expectations of standards of comfort and hygiene in the home and the effects of half a century of legislation commencing with the first Public Health Act of 1848.

Any large, well-appointed middle class home required a reliable water supply and in the mid-nineteenth century this was a major preoccupation for the builder. The supply of mains water by private or municipally owned water companies was then still in its infancy and few houses were connected to piped water. Each house, therefore, had to be self-sufficient in this respect. One source was spring water. Establishing its presence was an important preliminary to construction work and could even determine the precise location of a house and so sinking a well was the usually the first building operation undertaken before the foundations were laid. The circular shafts with a minimum diameter of three feet were lined with brickwork and most were no deeper than thirty feet, the maximum depth at which a common iron suction pump could function. Where possible the well was dug close to the proposed site of the scullery or kitchen. Spring water was – in theory, at least - relatively pure and safe to drink but it was usually hard and not suited to laundering purposes as it caused soap to curdle. For doing the weekly wash and for other scullery uses rainwater was used. An average sized roof yielded between 21,000 and 35,000 gallons of water per year and so many good quality houses were supplied with large rainwater storage tanks in the basement from which the water was again drawn by a hand pump.

Good quality houses available for letting were often advertised as having ‘both kinds of water’ but water remained a scarce and unreliable commodity until after about the 1870s. Spring water from relatively shallow wells was liable to contamination from leaking or overflowing cesspools and this was often the cause of local outbreaks of typhoid and cholera. The scarcity of water also circumscribed how people kept themselves clean. Bathrooms were rare before the 1870s and most middle class families used small portable baths of tinplate which had to be filled and emptied by hand using servant labour. On a daily basis many people washed themselves using a ewer and basin of water set on a wash stand in the bedroom.

By 1850, virtually all middle class homes were equipped with a water closet.

These were generally of two kinds: the valve closet and the pan closet. Both relied on a system of levers and cranks to operate a valve or pan to discharge the waste. The closet bowl and the mechanics were enclosed under a fixed mahogany seat and the flush water supplied from an overhead cistern which was typically filled by hand pumping water up from the basement rain water reserve. Pan closets were cheaper than valve closets and of a more robust construction but from the 1870s they were exposed as being unsanitary due to the impossibility of flushing clean their cavernous interiors. Both valve and pan closets were usually sealed from the soil pipe by the highly inefficient D-shaped water sealed traps which were not self-cleansing and often, therefore, the source of foul smells whenever the device was flushed. Sewage disposal was notoriously inadequate or even non existent at this time with WCs variously discharging liquid sewage directly into storm drains and ultimately into rivers or even into street gutters. Most decanted the sewage into cesspools dug in the back yards or gardens of the property and periodically these had to be emptied by nightmen who generally carried out this noisome task during the hours of darkness.

The family would usually take their baths in the privacy of their bedroom or in an adjacent dressing room but the water usually had to be carried up from the basement service area which would comprise a kitchen, scullery, pantry and larder and also stores for coal and ash. The service areas of the largest villas would also include a housekeeper’s room and butler’s office. Most service areas also contained a WC purely for servant use and in place of the expensive mechanical closets used by the family upstairs, they usually took the form of a simple ceramic basin attached to a water sealed trap. There were several variations of basin and trap closets according to the shape of the basin: thus there were long and short straight sided hopper closets whilst those with a rounded profile were known in the trade as ‘cottage’ or ‘servants’ closets’

The kitchen contained a large fireplace – typically five feet wide - whilst a large dresser was usually fixed on the opposite wall. In most substantial houses the water supply and the sink was located in the scullery along with a wash copper set in brick and containing its own small firebox. The sink was usually made of a hard sandstone or grit such as York stone and placed on a brick plinth below a window. The kitchen fireplace opening was usually occupied by a large cast-iron range consisting of a coal burning grate flanked by an oven and boiler. The range was either open to the chimney or enclosed on top by a hot plate which forced the hot draught to circulate around the oven and boiler before being lost to the chimney. These closed ranges were held to be cleaner and more efficient but in reality they consumed prodigious quantities of coal and were, besides, time consuming to maintain.

Coal fires were also the chief means of room heating. In the 1850s and 1860s, the principal rooms of a middle class villa were supplied with the fashionable ‘arch plate register grate’. The grate – as the name suggests – was framed by an ornate round arched opening. Immediately above the grate there was a small D-shaped hatch known as a register door which provided rudimentary control over the air supply to the fire and when closed sealed off the fireplace completely from the chimney flue. Small hob grates, which had the front fire-bars set between two cast-iron panels, were fitted in the fireplaces of the rooms on the upper floors.

The light of a coal fire was also a valuable source of artificial light although by the 1850s many middle class homes had gas laid on for lighting. Amongst the well to do, gas was regarded as excessively harsh and bright and, moreover, associated with use in industrial and public spaces: the soft light of oil lamps and candles was widely preferred. Nevertheless, the principal reception rooms were usually fitted with gas chandeliers – or gasoliers – suspended from a central ceiling rose. They were always fitted with a ball and socket joint to enable them to be moved to one side and with a water slide which enabled vertical adjustment. Gasoliers were made up of several simple flat flame burners usually of the ‘union-jet’ or ‘fish-tail’ pattern which were made of cast-iron or brass with the top of the burner consisting of some non-conducting material such as steatite, a natural stone which, after firing was practically indestructible. Two orifices were drilled at an angle in the top so that two streams of gas impinged on each other to spread the flame to something like the tail of a fish. They were poor light givers but lent themselves to gasoliers and lamps with globes of glass as they did not produce a ragged flame. The use of gas lighting on the upper floors was often restricted at this period to the landing and the average middle class family probably retired to bed by the light of a candle.

Downstairs in the service area, flat flame gas burners without glass shades were generally used. The kitchen was sometimes illuminated by a pendant light with two burners suspended over the main work table although bracket gas burners fixed to a round wooden block known as a ‘pattress’ were also widely used and fixed above the mantle shelf above the range. These had either fish-tail burners or the bats-wing burner made with a slit in a domed top. The bats-wing burner produced a good light but the flame was inclined to be ragged with ‘horny’ ends and so was not suited for use with a globe.

The services of a working class terraced house in the 1850s were simple in the extreme although our knowledge of the detailed arrangements of humble urban dwellings of this period remains scanty. Few families had their own water supply and had to rely on a communal pump in the street. Sanitary arrangements were also basic with many houses having a privy contained in a small structure behind the kitchen in the back yard. The privy consisted of nothing more than a fixed wooden seat with a round hole over a large void which connected to a brick lined cesspool via a short inclined drain. The cesspools were often shared between two or more houses and lacking adequate water and poorly maintained, they often became blocked and overflowed leading to stagnant pools of foul water accumulating in back yards and alleys. As a result, outbreaks of diseases such as smallpox, typhus and cholera were common. Some houses were supplied with WCs of the cheap hopper or cottage type but as the water level in these was confined to the trap below the basin they were inclined to accumulate solid matter; moreover, a source of flush water was often lacking altogether. Many ended up in a filthy state which only confirmed the views of many educated Victorians that the working classes were incapable of managing their own sanitary arrangements!

In the industrial suburbs of most northern industrial towns the water closet was virtually unknown and dry privies, which relied upon household ash to deodorise human excrement, were widely used instead. They were located in the small out-houses and the rows of these small structures was a common sight, across the north, lining the back alley ways in-between the rows of terraced houses. Where back-to-back houses were common, as in the mill towns of West Yorkshire, the closets were arranged in blocks at the ends of the terrace.

The typical plan of the industrial small town house was the ‘two up two down’ - just two main rooms on the ground floor - and two bedrooms above separated by the staircase. A small kitchen or scullery was located in a small single storey extension projecting into the back yard. A fireplace flanked by a wash copper and stone sink were usually built into the rear wall of the kitchen which is why these extensions almost invariably had a separate chimney stack from the main part of the house. Prince Albert encouraged the use of kitchen ranges in his model labourers’ cottages built in South Kensington for the Great Exhibition in 1851 but it is clear that most mid-Victorian working class kitchens had no cooking facility other than a simple open grate of iron bars set between masonry hobs. Information on the extent of gas lighting in new working class homes in the mid-century is almost entirely lacking but it is likely there was little or none. When the Industrial Dwellings Company built some working class tenements in Jacobs Wells in Bristol in 1875, gas lighting was laid on in the stairways and shared balconies but not in the rooms.

Towards the late nineteenth century, substantial improvements were made in the provision of services in urban housing although, inevitably, the benefits were more apparent in the middle class house. The most striking advance was the rapid adoption of the bathroom with fixed appliances supplied with running hot and cold water in larger houses after 1870. The coming of the bathroom represented a major change to the layout of the first floor plan rendering the traditional dressing room obsolete; it also had a huge impact on the way people lived and kept themselves clean. The key was the greater availability of mains water. During the 1860s and 1870s most towns and cities acquired constant supplies of pressurised, filtrated water either through municipally run concerns or through private companies. The practical difficulties of filling a full length bath were lifted once a connection to a mains supply was laid on. Fitted to a cold supply only, the bath water was heated by a small solid fuel or gas stove fixed to one end of the tub or by a gas burner attached underneath. It could take half an hour for the water to heat up but following the invention of the geyser by Benjamin Waddy Maughan in 1868, scalding hot water could be had instantaneously. The geyser consisted of a copper cylinder in which finely divided streams of water were heated by the rising hot gasses from rows of gas jets in the base.

The obvious disadvantage with the geyser and other similar heaters was that the hot water was usually confined to just one appliance. However, after1850, many larger households acquired closed fire ranges fitted with a back boiler which circulated hot water to a storage tank through flow and return pipes. This enabled hot water to be drawn off at any number of points in the house, including the kitchen or scullery, the bathroom and bedrooms. The earliest arrangement was known as the tank system and consisted of a circuit of flow and return pipes connecting the kitchen range boiler at the lowest point to a hot water tank at the highest point of the system and usually placed in the roof. The tank system was inefficient with heat loss a major problem but it also possessed one lethal weakness. Since all the taps were situated below the hot water tank it was possible to draw off water at the lowest point until the flow pipe was nearly empty so that any remaining water in the range boiler evaporated and it became red hot. If any water returned to the empty boiler it immediately turned to steam causing a rapid increase in pressure in the boiler which was sometimes enough to cause a catastrophic explosion. By the 1880s, the cylinder system had appeared as a safer and more efficient alternative. In place of the hot water tank in the roof, a hot water storage cylinder was placed just slightly above the range. The hot water was drawn off from the expansion pipe that extended upwards from the top of the cylinder to above the cold-water tank so there was no risk of the system being inadvertently emptied.

Bathroom fittings of the 1870s and 1880s were usually enclosed in mahogany panelling which provided some visual unity to the bath, washbasin and WC. From the mid-1880s, health reformers promoted the use of freestanding appliances that could more easily be kept clean. Cast-iron baths made with decorative feet and roll-top rims became popular in the 1880s along with washbasins supported by ornate stands of cast-iron and then in 1884, the new all-ceramic pedestal WC made its debut at the International Health Exhibition, South Kensington. The first pedestal WCs were of the wash-out type in which a shallow reserve of water was held back in the upper basin, separate altogether from the water in the trap below. Wash-out closets, however, proved to be difficult to flush and soon gave way to the wash-down closet which had just one level of water created by placing the trap at the back of the basin instead of underneath. The wash-down WC was easier to flush than other closets with the two gallon limit imposed by most water authorities on WC cisterns and by the early 1900s, the pedestal wash-down was established as the standard toilet for the middle classes. By the 1870s - in time for the adoption of the bathroom by the better off - many towns and cities had invested in the creation of sewerage systems so that the new bathrooms were connected to house drains which in turn led to sewers in the street. By the time the 1875 Public Health Act was passed, the urban cesspool was rapidly becoming a thing of the past.

Gas and coal continued to provide the main sources of energy in the home throughout the second half of the nineteenth century. After the 1870s the design of both coal burning ranges and open fireplaces was directed towards improving fuel efficiency. Slow combustion grates set low on the hearth within a low and narrow rectangular opening were introduced about 1870. Decorative glazed tiles which suited the prevailing fashion amongst the well to do for ‘aesthetic’ interior décor were often incorporated in the fireplace surround. By the1890s the sixteen inch wide bottom grate had become a trade standard and most fireplaces were fitted with ornate adjustable canopies to regulate the draught. By the 1890s, it was usual for virtually all good quality closed ranges to incorporate sliding and folding panels over the grate so that they could be quickly and easily converted to open fires when cooking was over in order to save fuel.

Between 1850 and 1900, the price of gas halved and by 1885 there were about two million gas consumers in England and Wales. Lighting was still the chief domestic application of gas but several important innovations brought a wider range of gas appliances into the middle class home in the late nineteenth century. The use of gas for heating bath water largely rested on the introduction of Dr Bunsen’s atmospheric burner in the 1860s. By combining air with the gas, the Bunsen burner transformed the yellow, luminescent flame into a hot blue flame capable of generating considerable heat. Atmospheric burners were also applied to cookers, heating stoves and even laundry irons. The use of gas for cooking had to overcome the innate conservatism of the average middle class householder – and of their cooks - but from the mid-1880s, gas companies began to stage cooking demonstrations to overcome popular prejudices. The result was a significant rise in cooking by gas at the end of the century and in Bristol, for example, gas cookers were used in 40% of households by 1908.

From 1885, gas lighting was improved following the development of the incandescent light by the Austrian, Carl Auer, Baron von Welsbach. His light worked on an entirely new principle. Whilst the light of flat flame and Argand burners was produced by raising the carbon particles in the gas to incandescence – that is, the flame produced the light - Welsbach used the atmospheric or Bunsen burner to create a hot blue flame. This gave no light itself but raised to incandescence the oxides of two rare metals: thorium and cerium in the proportion of 99% and 1% respectively. The incandescent gaslight was at least ten times more efficient than conventional burners although the use of the lamps at first was hampered by the difficulty of replacing the extremely fragile mantles impregnated with the two rare metals. From about 1905 inverted incandescent burners became available: these had the advantage that the light shone downwards without creating a shadow. Incandescent lighting by electricity actually predates its application to gas, having been introduced by Edison and Swan in 1879. Electricity for private use was first generated in Brighton and in Holborn in 1882 followed by parts of Kensington in 1887 but progress was slow and in 1910 only 2% of British homes had electricity.

The typical working class house of circa 1900 lagged far behind its middle class counterpart in terms of services and fitted equipment although standards were generally higher than fifty years earlier. The basic layout of the kitchen was little changed with a wash copper, fireplace and small sink built into one wall but by 1900, a kitchen range was virtually a standard builder’s fitting. The ranges were small – some just thirty inches wide - with a tiny oven but no boiler. Portable ranges’ which were, in effect, free standing cooking stoves on legs and with a stove pipe connection to the chimney flue were also commonly fitted in houses built in the 1890s and early 1900s. Many late Victorian sinks were still hewn out of a single piece of stone but following the introduction of fireclay sanitaryware by Francis T. Rufford of Stourbridge in 1850, fireclay sinks often finished with a buff glaze became increasingly common towards the close of the nineteenth century. Known variously as Edinburgh, Dublin and Belfast sinks, these were considerably more hygienic than those of stone which required constant scouring if they were not to acquire an unwholesome patina of green slime.

Most small terraced houses of circa 1900 were also fitted with gas lighting throughout the house. The main supply from the meter placed either under the stairs or inside the front door usually ran between the ceiling and the floor of the upper rooms and was usually fitted in the various rooms before they were plastered. The kitchen was usually provided with a swing bracket fixed on the mantle shelf whilst pendants were fitted in the two ground floor living rooms or alternatively, brackets were fixed each side of the chimney breast with another on the wall opposite. In the front bedroom the burner was usually placed between the two windows whilst in the middle and back bedrooms, one Edwardian gas fitter’s manual recommended placing the bracket on the window side of the chimney breast. Notwithstanding the wider availability of the incandescent burner from 1893, as late as 1907, the majority of gas lights in use were still flat flame burners. It was not until 1920, by which time there were seven million gas users, that flat flame and Argand type burners were declared nearly obsolete.

The introduction of the penny-in-the slot meter from the late 1880s enabled poorer families to pay for the gas in small affordable sums as they went along. At about the same time, many gas companies began to hire out gas cookers on cheap weekly rents and this brought gas cooking within the reach of the urban working class household. Unfortunately, the gas supply of the typical small houses rarely had a separate supply for cooking stoves with the result that when both stove and lights were in simultaneous use, both could suffer from too little gas. Nevertheless, by 1914, the use of the coal burning range in working class homes was rapidly giving way to cooking by gas.

It was in sanitary arrangements where the contrast between the working class terraced house and middle class villa was at its starkest. Bathrooms were rare at this social level. Few houses had running water beyond one cold tap in the kitchen and baths had to be taken by using portable galvanised baths with water heated over the range or in the boiler. The provision of WCs for small houses varied across the country: whilst Liverpool had complete provision by the early 1890s, Rochdale had only 750 WCs out of 10,000 houses in 1906 and in many northern industrial towns, use of the pail system or ash privy remained widespread. Where the WC was provided it was very rarely inside the house but usually located in a small out-house in the back yard of the property, often separated from the kitchen by a coal shed. At this period, free standing pedestal WCs was still largely confined to middle class homes and into the early 1900s, the wholly inadequate and insanitary hopper or cottage closets remained virtually standard in the smaller home. As they were not free standing they were embedded in plinths of rubble and mortar and fitted with a fixed seat of deal with a round hole cut out like the privy of old.

By 1890, the bathroom had reached down to the smallest middle class house – like the six roomed house ‘The Laurels’ in Holloway – occupied by the fictional London Clerk, Mr Pooter in ‘The Diary of a Nobody’, published in 1892. By the last decade of the nineteenth century, a new type of larger terraced house had emerged, consisting of modest villas each containing eight or nine rooms. These were homes for junior office workers - clerks like Pooter – or even for the upwardly mobile artisan class. Whilst not quite fully middle class in character, partly because they were still built in terraces, these houses, nevertheless, blurred the once clear distinction between the middle class villa and the small working terraced cottage home. They were well appointed with good sized reception rooms and handsome marble fireplaces whilst a bathroom was squeezed into the first floor plan between the middle and back bedrooms. The WC was of the pedestal type but in case a daily help was employed there was a second closet of a humbler type in the back yard. The plan and facilities of such houses were still rooted in Victorian and Edwardian building standards but in social terms, they anticipated the suburban homes built after the First World War for a rapidly expanding lower middle class.

During the First World War, house building came to a virtual standstill. When house building resumed in 1919, with the construction of the first council estates, entirely new house types with new standards of services and facilities were introduced as a result of the recommendations contained in the Tudor Walters Report of 1918. The design and layout of new homes and their services was now subject to entirely new pressures such as the spread of electricity and the expansion in car ownership. A new era of urban house building had begun.

David J Eveleigh

©2006 University of the West of England, Bristol
except where acknowledged