Plain Tiling Guide

This guide describes some common roof constructions and tiling details that are likely to occur in new and refurbished roofs.  Material specifications are provided and, where appropriate, these refer to new, or, proposed European standards.  The text follows the guidance given in the code of practice for slating and tiling, BS 5534, and includes some of the changes that are being proposed for the next revision of that document. Particular attention has been paid to best practice with respect to the ventilation of the roof space or batten cavity to prevent the buildup of harmful levels of condensation in the roof structure.

Certain recommendations have been included which represent more rigorous specifications than those found in relevant UK and European Standards. The CRTC believes that there are sound technical arguments for recommending what it believes to be Best Practice in such instances. For example, whereas BS 5534 specifies the use of 2.65mm diameter nails for securing the tiles to the battens, the CRTC recommendation is for 3.35mm nails. Designers and contractors may nonetheless exercise their own judgement in these matters bearing in mind both the minimum requirements specified in the relevant Standards and the CRTC recommendations. A companion guide Vertical Tiling is available. This guide pays particular attention to the securing the counterbattens and battens to the wall and also includes comprehensive illustrations of many common design details.

With the increasing sophistication of the housing market, the external characteristics of a house can play as significant a role as the interior appearance in the purchasing decision.  Eye pleasing, attractive features on the outside of the building add to its aesthetic appeal and make an immediate impression on the propective buyers before they walk through the front door.  And first impresions last.  A clay roof undoubtedly distinguishes a house as a premium ‘product’ and, to the builder, offers the potential for ‘added value’ which will exceed the marginal increment to the overall cost of the construction that may be associated with the use of clay tiles.

Clay is a natural material, which in the form of clay tiles has played an integral role in the UK’s built environment for over seven hundred years.  Clay roof tiles are durable, natural, sustainable products that improve with age and weathering.  Their appeal adds value to buildings and enhances the built environment.

Increasingly, concern for the environment is becoming a major influencing factor for the prospective homebuyers and builders.  Whether or not they have any influence, buyers are concerned as much about preserving the landscape as they are about the materials used in building and demand natural, sustainable products.  Clay tiles are considered by many planners and specifiers, as a sustainable product because of their durability, long term visual effect on the environment, and their properties as a renewable natural resource.  These factors, along with the fact that they are being specified increasingly by planners and conservation officers to preserve the character of buildings and the architectural landscape, mean that clay continues to be one of the most desired roofing products.  Recent evidence of the increase in the use of clay tiles is demonstrated by the fifty percent increase in the volume of clay tiles produced and sold per annum since 1995.

To support the renewed interest in traditional materials the CRTC members are making sure that a wide range of clay roof tiles are still available, producing more than 50 different colours.  These colours range from deep reds, browns, warm oranges and plum coloured hues of heather to the muted blues of Staffordshire.  Variations are obtained by controlling the kiln atmosphere to produce the rich heather shades. Colours of the tile can also be enhanced through the firing process to create a brindle effect, which varies the colour between the outer edge and the centre of the tile.  In addition, the firing process ensures that the colour of the tile is permanent and does not fade.  A panoramic view of the rooftops of Britain reveals a patchwork of colours, with each region set apart by its own, distinct clay roof tile colour.

Whilst durability is a major factor that influences architects, specifiers, conservation officers and planners, the ageing benefits of clay tiles also feature very highly.Clay tiles are unique in that they weather favourably and mellow with age, unlike other roofing products, further enhancing the aesthetic appearance of the roof.  They not only withstand the elements; they actually improve with exposure.

Clay tiles come in two main formats, the flatter plain tile and the larger format profiled tile.  Amongst plain tiles there are also other variations in the tile shapes including camber or curve.  Single camber tiles curve from top to bottom which reduces the capillary action between courses, while double or cross camber tiles are also curved from left to right adding another dimension to the roof.  A further design dimension can be added by using ornamental tiles, which can have curved edges such as the club and bullnose or beavertail ornamental tiles, a fishtail shape or a pointed end, commonly known as diamond or arrowhead ornamentals.