Pitched Roof - How to fix pitched roof

Refelting Flat And Pitched Roofs If the damage to a felted roof is too serious to repair, refelting is the solution, provided the underlying structure is in good condition. Simple pitched roofs, such as those found on garden sheds, are the simplest ; replacing a high-performance flat roof on house extension to lean-to garage is likely to be much more difficult, though not impossible.

In general, a shed roof has only a single layer of felt, but with a fairly generous overlap between sheets to keep rain out. The first step is to rip off all the old felt and remove the all the nails. Replace of repair the timber are sound. Treat al timber with preservative. New pieces of felt should be cut, making them 150-200m (6-8in) longer than the shed roof. Lay the first strip along the bottom of one side of the roof, smoothing an creased with a length of wood. Make sure the ends overlap the ends of the roof evenly and that the bottom edge overlaps the edge of the roof sufficiently to be turned down and project just beyond the eaves.

This allows rainwater to drip clear. Using 13mm(1/2in) roofing nails, to secure the top of the strip to the roof, the bottom to the eaves board and the ends to the fascias, folding the corners neatly, and repeat for the other side of the shed. Trim the excess felt from the ends of the roof. If the shed I large, lay a second strip on each side nailed at the top, but with the bottom overlapping the first sheet by at least 75mm (3in) and secured by adhesive, but nail the ends. Fit the fascia boards to cover the nailed edges at the ends of the roof.

Most flat roof shave two or three layers of felt, which will be a more durable type than that used on shed roofs. The top sheet will be capping felt, held don with adhesive. The first step is to strip off he all the existing felt down to bare timber and remove any guttering and flashing. When removing the old felt, notice how it is folded and cut at all the corners and edges- make sketches that you can follow later. Check the condition of the roof timber, repairing or replacing it as necessary. Remove all nails and sweep the roof clean. Most flat roofs have raised angled lip along two sides to direct rainwater to the third open side, where I flows into a gutter. The fourth side meets the house wall. Strips for the first layer of felt should be cut to slightly longer than the roof and nailed into place, working toward the gutter,using 18mm(3/4in) clout nails.

Allow an overlap of at least 50mm (2in) between strips. Make cuts so you can take the felt up and over the angled fillet t the house wall, following the sketches you made earlier. Trim the felt flush at the eaves. Cut a flashing strip about 150mm(6in) wide from the capping felt and lay this along the house wall so that it laps on to he roof. Tuck it into the lowest available mortar joint, having cut some of the mortar first.

If you are adding a second layer, stick it down to the first,using a continuous coat of felt adhesive. Cut the first strip to a different width so that the joints do not coincide with those of the first layer. Lay the first strip on the roof, roll it back half-way to apply adhesive underneath, then repeat the process for the other end. Carry on in this manner for the remaining strips, overlapping them by at least 50mm(2in)and applying felt adhesive along the overlap. Do not take the second layer over the raised lips.

The top layer should be stuck down in the same way as the second, but the detailing at the corners and edges will be different. Finish off by laying a second flashing strip along the house wall, fixing it into a higher wall mortar joint with fresh mortar, and a folded “apron” along each lipped edge.