Roofers: Roofing Guides

When to repair your roof — and when to replace it

This is the question we are asked most often. And the honest answer is that it depends on several factors that only a proper survey can assess. But here is a framework that helps.

Repair makes sense when: the underlying structure is sound, fewer than 20–25% of the tiles or slates need attention, the felt beneath is still performing, and the problem is localised — a section of failed mortar, a few slipped tiles, a flashing that has lifted. A good repair, properly done with matched materials, can extend a roof’s life by many years at a fraction of the cost of replacement.

Replacement is the right answer when: the felt has failed across a significant area (you can often see this as daylight through the roof space, or as widespread damp patches on ceilings), the tile or slate condition is deteriorating broadly rather than in isolated areas, or when the cumulative cost of ongoing repairs is approaching the cost of a re-roof. A full re-roof on a typical Merseyside semi starts at around £4,000–£6,000 and, done properly, should not need touching again for 40–50 years.

We will never recommend a full replacement when a repair will do the job. We also will not recommend a piecemeal repair when a roof has clearly reached the end of its serviceable life — because it is not in your interest and it is not how we build a reputation.

How to spot roof damage before it becomes a problem

Most significant roof problems start small and become expensive because they are not caught early. Here are the things worth checking, ideally once a year after the winter.

From the ground: Look along the ridge line for any tiles that appear raised or displaced. Check the line of the roof for any obvious dips or sags. Look at the chimney stack — if mortar around the pots or the flaunching (the sloped cement around the base of the pots) is crumbling, it is a job that will only get worse. Check the gutters: if they are pulling away from the fascia board, it may indicate rot in the fascia that is worth addressing before it becomes a structural issue.

From the loft: Any daylight visible through the roof covering is a concern. Staining on the rafters or felt indicates water ingress, even if it has since dried. A musty smell in the loft can suggest condensation or intermittent leaking. Check around any Velux or roof light frames — these are common leak points.

If you notice any of these, call us for a free survey. Identifying and addressing a problem early is almost always significantly cheaper than dealing with it after it has caused damage to ceilings, timbers or insulation.

Flat roof options explained — felt, GRP and EPDM

If you have a flat roof on a kitchen extension, porch, bay window or garage, you will at some point need to consider replacement. Here is an honest comparison of the options.

Traditional felt: Older cold-pour bitumen felt from the 1970s and 80s is reaching the end of its life right across Merseyside, typically lasting 10–15 years. Modern felt has moved on significantly since then. We fit a lot of high-performance torch-on felt — a properly specified 3-layer system with a mineral cap sheet, built as a full warm roof with insulation above the deck, is a genuine long-life option and one of our most common installations. It is not the same product as the old felt it's replacing.

Read our full guide to felt roof installation →

GRP fibreglass: This is what we install and recommend. A GRP flat roof is laid as a single seamless layer — there are no joins or seams for water to find. It is hard, durable, fully UV-resistant and carries a 25-year manufacturer system warranty. It can be walked on safely. It looks better than felt. The upfront cost is higher than felt, but the lifespan is two to three times longer, which makes it cheaper over any 20-year period.

EPDM rubber: A legitimate alternative to GRP, also long-lasting. We prefer GRP for domestic applications because of the seamless finish and the availability of manufacturer-backed warranties, but EPDM is a reasonable choice if specified correctly.

If you have a felt flat roof that is more than 15 years old, it is worth getting a survey. We can assess its remaining life and advise on timing honestly — without pressure to replace immediately if it is not yet warranted.

Why dormer roofs get condensation — and how a warm roof upgrade fixes it

Mould in the corner of a dormer ceiling, staining that follows the joist lines, a musty smell that won’t clear — these are the classic signs of cold-roof condensation, not a leak. We upgrade existing dormers to Building Regs Part L compliant warm roof specification, with every job signed off by an independent Building Control inspector rather than us.

Read our full guide to dormer roof warm roof upgrades →

Roofing on the Merseyside coast — what the sea air does

Properties within a mile or two of the Merseyside coastline — Southport, Formby, Hightown, Crosby and Ainsdale — face roofing challenges inland properties don’t: accelerated mortar decay, faster-oxidising lead flashings, and ridge tiles more prone to lifting in coastal winds.

Read our full coastal roofing guide →