Can You Replace Flashing Without a New Roof?

A roof is made of two kinds of parts: the covering across the slopes, and the metalwork where the slopes end. Flashing is the second kind. It lives at a chimney, against a wall, round a dormer cheek or in a valley, and it can wear out long before the tiles do.

Does bad flashing mean a bad roof?

No. A leak at a chimney with a perfectly sound covering is a very common call. The tiles or slates across the open slope may have years left, and only the lead along the wall has failed. Stripping a sound roof to cure a fault in one place would be wasteful and expensive.

The same goes for slate, clay and concrete. Whatever the covering is, the flashing is a separate item, fitted to it, and it can be renewed while the surrounding tiles are kept. A leak beside a chimney is therefore no reason to price a whole slope. That is the plain good sense of repair over replacement, and it is the choice we favour whenever the roof allows it.

The method is simple. Only the tiles or slates that overlap the old flashing are lifted, usually a few rows up the slope beside the wall or round the stack.

What happens to the tiles at an abutment?

At an abutment, where slope and wall come together, the roofer strips the covering back by a short distance, takes out the old lead and checks the battens beneath, the timber strips that carry the covering. Rotten battens are cut out and replaced, and any tears in the underlay sheet are found while the slope is open. New soakers and flashings are then fitted, and the tiles are relaid over them in the same order.

Tiles and slates are stacked carefully and put back, with new ones used only for any that break on the way. A chased or cut-in wall edge may also need re-pointing, the refilling of the mortar joint where the lead tucks in. Our page on lead flashing chased into a wall describes how that joint is built.

The job usually takes a short time compared with a re-roof, and the scaffold or access is set up to match. Waste is taken away and the site is left tidy.

A local repair is the default, but it is not always the answer. The survey looks for reasons to go further.

What would push the job beyond flashing?

If the tiles near the wall are crumbling or the slates are held on by rusted nails, lifting them to fit new lead may break more than it saves. If the battens and boards under the flashing have been wet for years and are rotten across a wide strip, that area needs rebuilding. And if the whole slope is close to worn out, spending money on one edge while the middle fails is poor value.

Then we tell you plainly, show photos of what we find, and set out the choice. Sometimes the flashing is the only thing wrong, and sometimes it is the first of several faults. A middle road exists too: renew the flashing now, and plan the wider work for a later year, once you have seen the pictures and know the state of the rest. Our guide to the signs of failed flashing helps you judge which is likelier before anyone climbs up.

Replacing flashing without a new roof rarely raises a regulation question. A like-for-like repair to part of a roof is normally permitted development under Class C, the planning rule covering re-roofing. A listed house still needs listed building consent for any work that alters its character, so check with Somerset Council's planning team first.

What should I ask before work starts?

Ask how far the covering will be stripped back, whether the battens will be checked, what weight of lead will be used and whether the new flashing will be oiled to avoid staining. Find out how rotten timber would be handled, so the price does not change without warning, and who clears away the old lead and broken tiles at the end. See our page on lead codes for the weights.

If scaffold is needed, ask who arranges the licence for any part on the public highway. We arrange it with the scaffolder. For the whole service, see lead work. The survey includes pictures of the flashing as it stands today, and the quote that comes after is a single total, in writing.