Repair or replace? How to decide what your roof actually needs

A leak doesn't automatically mean a full roof replacement, but it also doesn't mean a patch is always the right call. The decision comes down to the roof's age, the extent of the damage, and how much of it is isolated versus widespread.

When a repair is enough

If the roof is under 15-20 years old and the damage is isolated (a handful of cracked or slipped tiles, a small area of damaged flashing around a chimney or vent, or a single leak with a clearly identifiable source), a targeted repair is usually the right call. Repairs typically cost £150-600 depending on the extent and access required, and a competent roofer can often fix the specific issue in a single visit.

When replacement makes more sense

If the roof covering is past its expected lifespan (roughly 20-25 years for standard felt, longer for slate or good-quality tile), if leaks are appearing in multiple, unrelated areas rather than one spot, or if there's visible sagging in the roofline, patching individual symptoms stops making financial sense. You're likely to be back for another repair within a year or two. A full re-roof for an average semi-detached house typically runs £5,000-10,000+ depending on materials and roof size.

Questions to ask before agreeing to either

Ask the roofer to show you the specific damage, not just describe it: a photo from the roof itself, not just a verbal assessment from the ground. Ask how many other leaks or weak points they found nearby, since a roofer who's actually inspected properly should be able to tell you. And ask what the guarantee covers: a repair should come with at least a 1-2 year guarantee on the specific work, a full re-roof typically 10-25 years depending on materials.

The middle ground: partial re-roofing

If damage is concentrated on one side or section (common after storm damage), a partial re-roof of just that section can be more cost-effective than a full replacement while still addressing an aging roof covering properly, rather than patch-repairing an already-failing surface.

Getting a second opinion is genuinely worth it here: the gap between "needs £400 of repair" and "needs an £8,000 re-roof" is large enough that it's worth two verified roofers looking at the same damage before you commit.