Why Has My Roof Started Leaking Suddenly?

Ask What Changed

A roof that has been fine for years and starts leaking has usually had something happen to it. Working out what saves an enormous amount of searching.

Sometimes the answer is "nothing changed, the covering reached its point", and that is a real answer - but it is worth going through the list first, because most of the triggers are cheaper to deal with than a roof.

The Insulation One - and It Is Usually Not a Leak

This is the commonest trigger by a distance and the one nobody suspects.

Loft insulation is topped up. Damp appears in the winter. It looks exactly like a roof leak.

What has happened is that more insulation makes the roof space colder, because less heat from the house is getting up there. A colder roof space condenses more readily, and warm moist air rising from the house now meets a colder underlay and turns to water on it.

Worse, insulation is very often pushed right out over the wall plate at the eaves, blocking the ventilation gap that lets the roof space breathe. Now the moisture cannot get out either.

The tells: it appears in cold weather rather than during rain, it can happen on a dry frosty night, it shows as beads of water on nails and the underside of the underlay spread over an area rather than concentrated at a point, and it is worse above bathrooms and kitchens.

The fix is ventilation, not roofing. Clear the eaves, add vents if needed, and make sure extract fans vent outside rather than into the loft.

Somebody Was Up There

Any trade that has been on or near the roof is a candidate, and the leak often starts weeks later rather than immediately.

Aerial or satellite fitters - a bracket bolted through, or tiles walked on.

Solar installers - penetrations through the covering, and a lot of foot traffic.

Scaffolders - ties into the wall, and boards resting on the roof.

Chimney sweeps and flue installers - work at the stack disturbing flashings.

Window fitters - particularly at a bay or a dormer.

Anybody who cleaned the gutters off a ladder - the eaves course is the most commonly damaged part of a roof for exactly this reason.

If a leak started within a few months of any of those, say so when you call. It narrows the search to one area.

The Slow Ones

A tree that has grown into range. Trees do not stay the same size. A branch that cleared the roof five years ago may now be scraping it in a wind, or shading a slope that used to dry out, or dropping enough leaf to dam a valley for the first time.

A neighbour's work. On a terrace or a semi, work next door - a re-roof, a stack repoint, an extension - can disturb the shared parts, and on a continuous roof the effect appears on your side.

A previous repair reaching the end of its life. Sealant lasts a season or two, then cracks and holds water against the defect. A leak that returns worse than it was, a year or two after a repair, is often this.

Gutters that have gradually filled. Nothing failed; the volume accumulated until it stopped draining.

And the One That Is Not a Trigger

Sometimes the honest answer is that the covering reached its point and this winter was the one.

The pattern tells you. A single defect with an identifiable cause is a fault. Failures appearing in new places each year, at shortening intervals, with nothing to blame each time, is a covering.

On the Winsford estates that answer arrives in clusters, because the roofs went up together in the same materials in the same few years and have had the same fifty-odd winters. If your neighbours have started having work done, that is context rather than coincidence - and it is also the moment when sharing access across a run of houses makes the permanent work materially cheaper.