Damp patches on walls and ceilings are signs that your roof needs attention. Water entering a house can do a lot of expensive damage.
However, finding the leak can be difficult, as water does not always enter the roof just above the damp patch Often it travels some distance along the roof timbers before it drops onto the ceiling.
The best way to find the leak is to get up under the roof during a rainstorm. Take a torch and look for signs of water coming in. Follow the water to its source and push a length of wire up through the roof at this point so you can find it again when you are up on the roof in dry weather.
If you can’t get under your roof, about the only solution is to go up onto the roof and plug all visible holes. Most leaks are traceable to buckled, split or missing tiles and damaged flashing.
Once you find the leak, wait until the rain has gone to start repairs. When working on the roof take great care. Wear soft-soled shoes such as tennis shoes because most roofing materials are easily cracked, adding to damp problems. Avoid stepping on the edges of tiles and try to work in warm weather when tiles are less brittle and safer to handle.
Terra cotta tiles are usually laid in an overlapping pattern. Movement of the tiles often causes leaks. If the crack is a clean one it can be repaired with suitable roofing cement. Alternatively, slide a sheet of aluminium flashing under the tile so it extends past the butt of the tile in the next course above. Fix the flashing in place with roofing cement. To replace a tile, lift the tiles next to it, cutting the wire ties holding it if necessary. Use wooden wedges to hold adjacent tiles clear so you can lift out the broken tile. Insert a new tile and gently remove the wedges Ensure edges interlock correctly and renew the ties in the ceiling cavity. If crumbling mortar at the ridge capping is the problem, carefully chip out the old mortar and use a concrete binding material in the new mortar mix to ensure good adhesion. A crack in the ridge capping is best sealed with silicone sealant. There are special types of sealants on the market, building and household. That will suit most jobs around the home. If the crack is too large to fill, you may have to replace that particular capping tile. This involves chipping out the old mortar carefully all around the tile. So as not to disturb the rest of the capping. Ensure the new piece of capping is bedded firmly into place, and sealed with mortar mix.
Metal and fibro roofs.
Cleaning the area thoroughly and repairing with a plastic sealer can repair small holes. A flexible sealer such as silicone is recommended to prevent cracking during hot weather. Embedding a patch of the same roofing material can make temporary repairs in silicone caulking compound.
To mend leaks in slate, insert a piece of flashing under the slate, over the hole and secure it in place with roofing cement. Make sure the flashing extends up beyond the butt of the tile in the course above.
Pushing a piece of aluminium flashing up under the shingle, over the hole, can repair leaks. Ensure the top of the flashing is above the bottom of the shingle in the course above. If the flashing won’t push up past the bottom of the shingle in the course above, slide a hacksaw blade underneath the shingle and saw off the nails that most probably are stopping it. Use a sealant to seal nail holes and overheads of nails. Repair splits by first inserting the flashing as described then driving nails in on each side of the split, as close as possible to the bottom of the overlapping shingle. If a shingle is missing cut off the nails that were holding it in place and, insert a new shingle, held in place with nails driven just below the butt of the overlapping shingle. Some shingles, such as asphalt, require a combination of special roofing cement and nails to hold them in place.
Flashing is the metal or plastic sheeting that diverts rain away from chimneys, pipes, joins between gutters etc. The flashing should be checked once a year to ensure no holes are developing where water can penetrate. Loose or leaking flashing can be plugged with a suitable sealing compound worked into the crack with a putty knife. Sometimes all that is needed is to bend the flashing back down again properly to ensure it is in contact with the guttering or roof surface. (See also Valleys and Flashing).
Materials you’ll need:
• Roofing cement
• Lengths of wire
• Flashing material
• Wooden wedges
• Roofing cement
• Concrete binder
• Metal or fibro, patches if required
• Sealing compound.
Tools you’ll need: