Most often, roof truss clips are included in your overall quote. However, should you need to buy these, you would be looking at a cost of around 25-40p per clip – a very minimal cost. This is a small price to pay to ensure your designs are validated and safe. All members should be accurately located. Purlins and binders should be built in, where necessary. In a typical traditional roof, the basic timber members are: Ridge and hip tiles, for a distance of at least 900mm from the face of rigid masonry supports such as gables, abutments and separating walls, should be mechanically fixed.

Battens should be fixed with cut or wire nails. The nail shank can be smooth, annular ringed or helically threaded. Nails can be steel or aluminium. In coastal areas, steel nails should be hot dip galvanized. (d) slates and tiles Battens on rigid sarking boards should be supported on counter battens to allow free drainage of any water that may reach the underlay. Counter battens should be fixed through to the rafters and not to the sarking boards alone. Battens should be fixed through counter battens to rafters.It is essential when installing celotex rigid insulation boards in cut to fit roof applications to ensure they are secured firmly. Insulation boards falling down on your head is no fun and also you really don’t want the weight of the boards resting on your plasterboard finish. Celotex insulation clips are and ideal purpose made fixing that ensures the PIR insulation boards are kept firmly in their place. The advantage of these clips is that if you have uneven timbers or if you are unable to cut the insulation to fit tightly in between the timbers. Then these fixings will work perfectly holding the insulation in position. Particular care is needed where pipes project through the underlay. Torn underlay around pipes can lead to the ceiling becoming wet and stained. Cut a small cross in the underlay and sleeve over the pipe so that the tongues turn up. Two clips are used per roof truss. One is placed on either side, where the truss is fixed to the wall plate. Usually, the roof truss clip is installed on the inside wall plate. However, you can also fit these on the outside wall plate if the detail of the truss heel allows.

To prevent the underlay sagging at the eaves and forming a water trap behind the fascia, it is recommended that the underlay is supported by a continuous fillet. Where the pitch is below 30°, a continuous fillet should always be used. Plain tiles are unsuitable for pitches less than 35°. (b) verges

Careful setting out makes the actual tiling process faster and will influence the finished appearance on the roof. It helps to avoid problems such as unequal overhangs at verges and often makes it possible to avoid excessive tile cutting at abutments, chimneys and similar obstructions. Where underlay laps are not under a batten, an extra batten should be used to prevent the underlay lap opening due to wind uplift. The British Standard for trussed rafters, The Trussed Rafter Association and the NHBC handbook amongst other sources of information provide guidance on the bracing of trussed rafter roofs. Trussed rafters can almost be considered as a thin playing card in terms of their robustness about their weaker axis. Therefore for their stability and for the stability of the other roof a series of diagonal bracing and longitudinal bracing is required to ensure stability. A truss is so much more than the sum of its parts. Any alteration to a truss once manufactured is likely to be involved and costly. Surveyors and Inspectors need to be vigilant in spotting unauthorised alterations. Sin No 2 Unauthorised alterations All abutments should be weatherproofed using non-ferrous metal flashings. Lead flashings should be at least Code 4 (colour coded blue), while soakers are normally Code 3 (colour coded green). Normally, lead flashings should not exceed 1.5m in length, with laps of not less than 100mm.