Materials - Walls and Roofs

Building Materials

Throughout older parts of Letchworth Garden City there are countless surviving examples of simple designs, effective detailing and original materials which provide a model for carrying out repairs and new works. When contemplating any building works, you should always start by looking at the primary materials and detailing of your own house. There are special considerations for Early Garden City Houses.

Building regulations were introduced by the original developers of the Garden City to ensure that good housing design was not spoilt by unsuitable materials and poor detailing: 'A high standard of beauty... can only result from simple and straightforward building and the use of good and harmonious materials' . 'Useless ornamentation' was discouraged, and simple house designs were made more effective by the attention given to chimneys, roof eaves, dormer windows, porches, doors and windows. From the beginning, the exercise of strict controls ensured a small but good quality range of natural building materials, and this contributed greatly to the present, striking character of the Garden City.

Roofs & Tiles

Tiles

Most of the early houses in Letchworth were built with steeply pitched roofs of 45-50 degrees, hung with plain clay tiles. Gables and dormer windows created a lively skyline. Since that time roof pitches have gradually become lower and machine-made concrete tiles have been introduced.

Whatever the age of the house, care should be taken, when replacing a roof or building an extension, to match the original tiles and roof pitch as closely as possible. On Listed Buildings, tiles must match the original. This may involve the use of good reclaimed tiles and owners are expected to re-use existing, undamaged tiles. Often it is the fixings, rather than the tiles, that have failed so that, with care, the original tiles can be reclaimed and re-laid. If new tiles are necessary, Council or Heritage Foundation staff will be pleased to advise which ones would be acceptable.

Owners are reminded that grants may be available to help with the cost of re-roofing older properties with matching replacement tiles. It is best if owners of semi detached or terrace properties can co-operate to re-roof at the same time and use the same materials. This can also reduce the cost of the work. If one house in a group has been retiled, then it is likely that the tiles used will become the standard for future retiling on other houses in the group.

Roof features

Design details of roofs are very important. Owners should look carefully at the existing roof in all its details and try to copy these. Look out for the following features in traditional Garden City houses:

• gables with a tiled undercloak rather than wooden bargeboards
• open eaves where the feet of the rafters are visible, and support guttering brackets the use of short rafters fixed near the bottom of the roof,
• softening the angle on hipped roofs, the use of well-bedded bonnet hips, rather than bulky, half round ridge tiles
• swept valley junctions, rather than a valley gutter, between projecting gables or dormer roofs

Bricks and external walls

Many original Garden City houses had a roughcast cement finish. Some were left as unpainted 'pebbledash', others were given a cream/off-white colourwash. Plinths were natural red-brick or black-tarred. Woodwork was black, green or cream painted. Today a wider range of paint colours is available, but the originals are to be preferred and can be quite easily reproduced.

It is, however, most important that terraces, planned groups and semi-detached properties adopt the same overall colour scheme. Red stock bricks were widely used and good reclaimed materials can usually be obtained to give the best finish to new building work. If new bricks are to be used they should blend with the existing in general colour, shading, and size.

It is also important to match the jointing or pointing: most early Garden City brickwork used lime mortar with a flush joint wiped with sacking to give a rough texture. Modern 'struck' joints finished with a metal trowel should be avoided. In important early Garden City buildings, it may also be necessary to match the original brick bond.

Artificial cladding of Garden City houses is generally aesthetically unacceptable and will be resisted by the Council or by the Heritage Foundation within its estate. (In Conservation Areas such work would need planning permission and would be resisted by the District Council).

Owners of listed buildings must apply for Listed Building Consent from the District Council if they intend to paint their properties a radically different colour, or paint over surfaces that are unpainted. Any unsympathetic alterations will be resisted.