Roof repair: when to call someone

Roofs fail slowly and then suddenly. A cracked flashing lets in a trickle for years before a ceiling shows a stain, and then one storm takes out half the ridge. Most of the diagnosis can be done from the ground with binoculars, which is also the safest place to do it.

What the ground will tell you

Stand back and look along the roof line. A run of tiles that has dropped out of line, a sag between the chimney and the ridge, or a row of ridge tiles with missing mortar are all visible from the front path. Binoculars turn a short walk into a full inspection of the covering. Do this after any storm, and photograph what you see so you can tell a new problem from an old one.

Then look at what the roof sends water into. A gutter that sags away from the fascia, a downpipe that stops short of the drain, or staining on brickwork below a valley tells you where water has been going for months. Water tracks sideways under tiles for surprising distances, so the leak in a bedroom is often nowhere near the gap outside.

• Slipped tiles - Usually a broken nib or a nail rusted through.
• Ridge mortar - Crumbling mortar on older roofs lets water in along the top edge.

The small jobs that stay small

A few roof-adjacent jobs are reasonable for a careful homeowner. Pushing a hose up a downpipe from the ground to check it runs clear needs nothing but a helper turning the tap on. Cleaning a gutter you can reach safely from a ladder on firm ground, with someone footing it and both feet below the top three rungs, is acceptable for anyone comfortable with ladders and nothing else on the drive.

Beyond that the line is clear. Anything above gutter height on a two storey house, anything needing a ladder rested on the gutter itself, and anything that involves standing on a roof surface is professional work. Ladder work looks simple right up to the point where it is not, and the consequences do not scale with the size of the job.

• Reasonable - Clearing a low gutter from a stable ladder, checking a downpipe, zooming in with a camera.
• Not reasonable - Walking a pitched roof, carrying materials up a ladder, working one handed.

Why this is worth paying for

Falls from height cause more serious DIY injuries than any other kind of home repair, and the people hurt are usually experienced rather than reckless. Roof surfaces are fragile in ways that are not obvious. Old cement sheets, common on garages and outbuildings built before the year 2000, may contain asbestos and can crack under a foot. Tiles cracked in frost may not leak for a year.

A roofer arrives with a ladder that reaches, a roof ladder that hooks over the ridge, and insurance covering the consequences of a mistake. Compare that against a day off work with a broken wrist. There is no version of this calculation where doing it yourself is the sensible choice, and that includes pulling a branch off the roof after a storm.

• Roof ladders - Hook over the ridge and spread weight across tiles. Household ladders do neither.
• Insurance - A professional's policy covers damage and injury. Yours will not cover your own fall.

Flat roofs, chimneys and flashing

Flat roofs fail differently from pitched ones. Blisters, where the membrane lifts off the deck, and ponding, where water sits for days after rain, both shorten the life of the covering. A flat roof that has started to puddle is not something a coating fixes for long, whatever the tin promises. The reliable answer is a new covering specified in writing, with a guarantee that names what is covered.

Around a chimney or a dormer, most leaks are flashing failures rather than tile failures. Lead dressed into a chase in the brickwork and pointed properly lasts decades, while mastic smeared over a joint lasts a winter. If a leak appears near a chimney after a dry summer, suspect the mortar rather than the lead, and ask whoever quotes what they think failed.

• Ponding - Water still there 48 hours after rain means the falls have gone.
• Flashing - Look for lifted lead, cracked mortar and old mastic patches.

Hiring someone and handling storm damage

Get three quotes for anything beyond a minor repair, and make sure each one describes the same job. One roofer quoting for a patch and another quoting for a whole elevation are not comparable, and the cheapest number often reflects the smallest scope. Ask whether scaffolding is included, who arranges it, and how long the work will take. Scaffolding is a large part of the cost of any job at height.

After a storm, cold callers appear within days. Legitimate roofers are usually busy for weeks after bad weather, so anyone offering to start tomorrow should be checked carefully: a landline, a verifiable address, and a written quote before work starts. If you are claiming on insurance, photograph the damage before anything moves, tell the insurer before work begins, and keep receipts for any emergency cover such as a tarpaulin.

• Quotes - Same scope, scaffolding included, start and finish dates named.
• Insurance first - Report damage before permanent repairs. Insurers rarely pay for work done first.