Flat roof surveys and leak tracing across Gwynedd

Guide price

£140–£280

Repair price

Confirmed once the leak or damage is found

Condition survey report

£140–£280

Coverage

England, Wales, Scotland, NI

How much does a flat roof survey cost in Gwynedd?

Guide prices including VAT at Wales rates. We confirm the price once we've traced the leak or seen the damage.

Which flat roofs are common in Gwynedd?

Flat roofs in Gwynedd sit on terraced streets with flat-roofed rear kitchens and bathrooms, bungalows with flat-roofed side extensions and dormers and 1930s semis with flat-roofed garages and kitchen extensions. Wales averages roughly 1,460 mm of rain a year, among the wettest in Britain, so we design for steady run-off: proper falls, clear outlets and upstands well above the finished roof. Approximate 1991–2020 regional averages based on Met Office data.

Building regulations in Wales

Welsh guidance is that most re-roofing needs building control approval, so it's worth checking whenever more than a quarter of a roof is replaced or repaired. Renovated roofs are upgraded to around 0.16 W/m²K where feasible, and new extension roofs are built to 0.13 W/m²K under the Welsh Approved Document L. In Gwynedd the application goes to Gwynedd Council. More on the rules.

How do you find where a flat roof is leaking?

By working from the evidence inside back to the likely entry points outside, then confirming the path with moisture readings and, where needed, small test openings.

We start indoors, looking at where the staining is, when it appears and whether it follows rain, wind from one direction or cold weather. Then, on the roof, we check the details where most leaks start: upstands and flashings, laps and seams, outlets, gutters, edge trims, rooflight kerbs and anything that passes through the covering. Walls, copings and cavity trays above the roof are checked too, because water getting in behind an upstand can look like a roof leak.

A moisture meter shows where the covering, or the material beneath it, is holding water, and readings across the roof help map how far the wet has spread. Meter readings are a guide, not proof, so where they suggest a problem we may take a core sample: a small cut through the covering and insulation to see what is underneath and whether the deck is sound. The opening is sealed again with compatible material before we leave.

Condensation can also look like a leak, especially in older cold roofs without adequate ventilation, and the survey considers that possibility too. The flat roof leaks guide explains the common causes.

How long does a flat roof survey take and how long is it valid?

A survey of a typical garage or extension roof usually takes an hour or two on site. Larger, higher or multi-area roofs take longer, and the written report follows afterwards.

A survey describes the roof on the day it was inspected. It stays a useful baseline for planning, but roofs change, particularly older ones and after a hard winter or a storm. If you are using a report to plan a replacement some time later, or after a fresh leak, a short follow-up check is sensible. For roofs you manage over the long term, a regular inspection backed by the maintenance checklist picks up problems early.

Which towns in Gwynedd do we cover?

• Bangor, Gwynedd
• Caernarfon

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