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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.
Tiled
roofs.
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.
Slate
Roofs.
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.
Cedar
shingles.
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
problems.
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).
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