Finding a roof leak means following the water back to where it gets in, which is rarely where it shows. Here is how we work it out, and what you can safely check from indoors first.
A stain on the ceiling tells you where the water ended up, not where it came in. On a Keynsham roof the entry point can be some distance away, because water slides along felt, battens and rafters before it finds a way down. Tracing it properly takes a methodical look inside and out.
Start in the loft, with a torch
With the light on and the hatch open, look for daylight where there should be none, dark or damp timber, and felt that is stained or sagging. Drip marks on the underside of rafters often point towards the entry. Keep your feet on the joists. If you can see daylight at a particular spot, mark it from below with a note on the ceiling or a photograph, which saves us time outside.
Follow the line upwards
Water runs downhill, so the opening is almost always higher than the wet patch. We trace the stain back along the rafter to the highest point of dampness, then look at what sits above it: a tile, a ridge, a valley, a flashing, a chimney or the edge of the roof. This is why a patch of damp over a bedroom door can turn out to be a flashing round a chimney on the other side of the roof.
Usual suspects on the outside
From the ground and then on the roof itself, we look at the common weak points one by one, because a leak is usually down to a single fault rather than general wear. Some of these can be spotted from the pavement with binoculars, though close inspection is what confirms them.
- Slipped, cracked or missing tiles and broken slates
- Lead flashings at chimneys, walls and valleys that have lifted or split
- Ridge and hip mortar that has cracked
- Gutter edges and verges where water can get behind the covering
Why older roofs make it harder
Many Keynsham homes are Victorian and Edwardian, with older felt, or none at all, under the covering. There the water can show up in a room far from the fault. Estates from the inter-war and later periods usually have simpler roofs, but ageing felt and shifting tiles can still send water a long way sideways before it appears.
What not to do
Please do not climb up, use a ladder to the roof or hose the roof to try to find the leak. That is risky and can push water into places it would not otherwise reach. Note when the drip happens, which wind direction brings it, and take photographs, then call us and we will find it safely.
Frequently Asked Questions
Can a hose test find the leak?
We would rather not rely on it. Soaking one area can force water in where it would not normally go and confuse the result. Careful inspection from the loft and across the roof usually finds the cause more reliably.
Why does the leak only show in some weather?
The opening may only take water when rain is wind-driven from one direction, or when a heavy downpour overwhelms a valley or gutter edge. Noting the conditions when it happens helps us narrow the search a good deal.
What if you cannot see an obvious fault?
Then we work through the likely routes in turn, starting from the highest damp point and checking flashings, ridges, valleys and edges. Occasionally the cause is condensation instead, which we can tell from the pattern of the damp.
Talk to our team about roof repairs in Keynsham
Every roof is different — the fastest way to get an accurate answer is a quick chat with our team.