Signs of a roof leak, inside and out
A roof leaks for months before it shows. Here is where it shows first.
Where to look
On the ceiling
A brown ring, or a patch of paint that bubbles or flakes. If it darkens or spreads after rain, it is the roof. If it is the same in dry weather, think pipes first.
In the loft
With a torch, after rain: a dark wet patch on the felt or a rafter, drips, daylight through the tiles, or insulation that is damp or stained. Look uphill from any wet patch, not just above it.
From the garden
A tile sitting lower or crooked in its row, a gap showing dark felt, a ridge tile out of line, flashing lifted at the chimney, or pieces of tile in the gutter or on the ground.
Why the leak is not where the stain is
Under the tiles is a layer of felt or membrane, laid in overlapping strips down the slope. Rain that gets past a slipped tile lands on the felt and runs down it, sometimes a long way, until it finds a tear, a nail hole or a lap it can get through. Then it drops onto the ceiling below. So the stain marks where the water came out, not where it went in — and finding the way in is the part that takes an eye.
Uphill of the stain.
Water runs down the felt and along the rafters before it drops. The entry point is usually above and to one side of where the stain appears, sometimes by metres.
More guides
Why gutters overflow, and what it does to a house
The four causes of water over the edge, and why the wall underneath is the real cost.
02How often should gutters be cleaned?
Twice a year for most houses. Which houses need more, which can go longer, and how to tell.
03Moss on the roof: why it matters more than it looks
What moss does to tiles and gutters, why some roofs grow it and others do not, and how it should come off.
04After a storm: what to check from the ground
A ten-minute walk round the house that finds most storm damage before the next rain does.
05What a roof and gutter inspection covers
The six things that get looked at, and what each one tells you.