Flat Roofing in Horsford - Repair or Replace?

Expert Flat Roofing
in Horsford

Flat Roofing on Extensions, Garages, and Outbuildings

Flat roofs on extensions, garages, and outbuildings are common across Horsford and the surrounding area. They are practical structures, but they need the right system installed correctly to avoid the leaks that have given flat roofing a poor reputation. At North Walsham Roofers we install EPDM rubber and felt flat roofing systems across Horsford, North Walsham, and the wider area including Norwich and villages such as Wroxham and Stalham.

When something goes wrong, the first thing to work out is whether a targeted repair is the right answer or whether the roof has reached the end of its useful life. Getting that decision right saves money and avoids the frustration of paying for a repair on a roof that needs replacing.

When a Repair Makes Sense

A repair is the right option when the underlying deck is sound, the membrane or felt is otherwise in good condition, and the failure is genuinely localised. These situations do exist, and a good repair on a roof that still has life in it is entirely worthwhile.

Typical scenarios where a repair is the correct call:

• A single seam or lap joint in a felt system has lifted or opened up, allowing water in at one point. The rest of the roof is intact and bonded correctly.
• A flashing where the roof meets a wall has come away or cracked. The membrane itself is undamaged and the deck is dry.
• An outlet or gutter has blocked and caused localised ponding that has started to lift the edge of the membrane. The surrounding area is sound.
• A small blister has formed in a felt system but has not cracked through. Cutting, drying out, and re-bonding can resolve this before it becomes a leak.

In each of these cases, the repair addresses the actual cause of the problem. The surrounding roof has enough remaining life to make repair worthwhile.

When Replacement Is the Honest Answer

A repair is not the right answer when the roof is failing in multiple places, when the deck beneath is compromised, or when the membrane has degraded across its whole surface. Patching a roof in this condition is temporary at best and costly at worst - because you will be paying for the repair and then paying for the replacement shortly afterwards anyway.

Signs that replacement is likely the better decision:

• The felt has multiple cracks, blisters, or splits across different areas of the roof - not just one location.
• Water has been getting in long enough to have softened or rotted the deck boards beneath the membrane. Soft spots underfoot when walking the roof are a clear indicator.
• The roof has already had several patches applied over the years. Each patch changes the surface profile slightly and makes the next repair harder to seal correctly.
• The existing system is more than fifteen years old and showing its age throughout, not just in one spot.
• There is significant moss or algae growth that has been there long enough to have lifted the surface and allowed moisture underneath.

A flat roof that is failing in several places at once has usually reached the end of its serviceable life. Repairs at this point become a cycle rather than a solution.

The Deck: The Factor That Changes Everything

The condition of the deck - the boards or sheets that form the structural base of the roof - often determines whether repair or replacement is the right call more than the membrane condition does. A membrane can be replaced relatively simply. A deck with rot or delamination cannot be covered over without creating a bigger problem later.

When inspecting a flat roof, pressing firmly on the surface in several places gives a rough sense of deck condition. Any give or soft areas suggest the boards have taken on water. A proper inspection involves lifting a corner of the membrane to check the boards directly. Any replacement of the membrane should include a full deck inspection and replacement of any damaged sections before the new system goes down.

Choosing the Right System for a Replacement

If the decision is replacement, the two main systems for domestic flat roofs are EPDM rubber and built-up felt. EPDM is a single-ply synthetic rubber membrane that is bonded to the deck and dressed into all upstands and outlets. It handles freeze-thaw cycles well and, when installed correctly, has a long service life with very few seams to open up.

Built-up felt, particularly torch-on felt using a quality SBS-modified capsheet, is still appropriate for many garage and outbuilding roofs. It is installed in two or three bonded layers and is generally lower in cost than EPDM. The joints and flashings are the areas to watch on any felt system, and they need to be properly lapped and sealed at every upstand.

EPDM typically costs around £70 to £120 per square metre installed for a straightforward replacement. Torch-on felt generally comes in at £40 to £80 per square metre installed. These figures vary based on deck condition, access, and the complexity of any abutments, parapets, or outlets. A like-for-like replacement on an average garage roof in Horsford might cost £900 to £2,000 in total - more if the deck needs significant work.

What to Ask Before Agreeing to a Repair

Before agreeing to a repair on any flat roof, ask the contractor to explain exactly where the water is getting in and why. A good answer is specific: