Flat Roof Repair Hampshire

Brown staining on the ceiling below the roof indicates active water ingress through the flat roof covering. Leaks frequently enter the building some distance from where the internal stain appears, as water travels along timber joists and insulation seams.

A drip above your kitchen sink can originate several metres away on the roof surface. Tracing the true source requires professional diagnostics using a moisture meter, thermal imaging, and a controlled water test.

Bubbles or blisters across the field membrane indicate trapped moisture or air between the membrane layers. A garage ceiling dripping after severe weather often points to a single seam fault, but blisters spread across the field may require more extensive repair.

Blisters can burst in warm weather, exposing the underlying layers to water ingress. Each of these signs points to a developing fault that requires professional flat roof repair to prevent further deterioration.

Open laps where two sheets meet show that the adhesive has failed and the joint is no longer watertight. Lap and seam failures form one of three main leak categories, alongside surface defects and detail failures.

Most recurring leaks begin at a poor edge or upstand rather than across the open membrane, which is why detail work receives the closest attention during repairs. Open laps require a matched membrane patch bonded with full overlap and primed preparation.

Cracks running parallel to upstands or trims indicate stress at the perimeter where the membrane meets walls or flashings. Detail failures at upstands, outlets, chimney aprons, and skylight curbs are a significant source of recurring leaks.

A leak at an upstand or chimney is addressed by lifting the existing flashing, re-dressing the membrane, and chasing a new lead apron into the wall. Applying mastic over the joint is not an effective solution and provides only temporary relief.

Puddles that remain 48 hours after rain has stopped show that the roof has insufficient fall or that drainage is blocked. Standing water in this way points to accumulation where the surface should be clear.

Flat roofs in Hampshire endure the combined effects of rain, sun, and salt air, which frequently leads to clogged outlets and water accumulation. Both garage seam faults and field blisters on porch roofs require professional flat roof repair to restore effective waterproofing.

We begin with a free site survey, moisture mapping the deck, photographing the membrane, and recording every defect. Three factors help the visit proceed efficiently: a clear phone description of the leak, a photograph or short video of the ceiling stain, and safe parking with unlocked side access.

Leaks are categorised into three groups: surface defects (splits, blisters and punctures), lap and seam failures (separated joints and bond breakdown), and detail failures (upstands, outlets, chimneys and skylights). This diagnostic approach establishes the true source before any repair work begins.

Wet sections are lifted and the deck is dried when weather conditions allow. A rotten deck requires the replacement of affected boards before any membrane is applied, as bonding a new patch over wet timber risks failure within months.

We lift the patch zone and probe each board with a moisture meter, replacing any board with readings above 18%. We also inspect the joists beneath at their bearing ends for rot, then fix new OSB or plywood at 150mm centres.

A matched membrane patch is bonded with full overlap and primed preparation. Each flat roof repair is matched to the existing system: felt with felt, EPDM with EPDM, GRP with GRP, and single-ply with single-ply.

Felt roofs require SBS-modified torch-on or cold-applied patches. EPDM roofs need a primer-and-tape splice within the same rubber family. Reinforcement weight is a critical consideration, as a heavier patch on a lighter system can stress the joint line.

Flashings, kerbs, and outlet collars at the perimeter are re-dressed to ensure proper sealing. A durable flat roof repair depends on the deck being dry, the system being matched, and the perimeter being correctly re-dressed.

A proper repair at an upstand involves a fresh chase 25mm into a mortar joint, a code 4 lead apron dressed 75mm down, a bonded membrane upstand of at least 150mm, and a trim bar at 300mm centres. This detail is capable of withstanding five winters without movement.

A flood test or hose test of the repair is carried out before sign-off to confirm that the leak has been resolved. Each repair includes a deck moisture check and a system-matched patch, with a fresh seal applied to at least one perimeter detail.

A temporary application of mastic provides only short-term relief. Our van is equipped for emergencies with cold-applied bitumen patches, self-adhesive flashing tape, heavy-duty tarpaulins, and weighted sandbags for temporary coverage while the permanent repair is scheduled.

We respond within 48 hours on every flat roof leak callout. If your flat roof requires an emergency roof repair, we will respond within 24 hours.

Three factors help speed up the visit:

• A clear phone description of the leak
• A photograph or short video of the ceiling stain
• Safe parking and unlocked side access on arrival

A temporary patch can be applied in wet weather, with the permanent repair scheduled for the next dry window. We bond cold-applied membranes to damp substrates for short-term coverage.

We do not carry out hot-air welding during rain, as torch-on work requires a dry deck and liquid waterproofing requires a dry surface to cure.

Our van is equipped for emergencies with:

• Cold-applied bitumen patches
• Self-adhesive flashing tape
• Heavy-duty tarpaulins with brass eyelets
• Weighted sandbags

Your property remains protected while we schedule the permanent repair for the next suitable window.

A leak at an upstand or chimney is resolved in three steps: lifting the existing flashing, re-dressing the membrane, and chasing a new lead apron into the wall. Applying mastic over the joint is not an effective long-term solution.

Most recurring leaks on Hampshire flat roofs that we attend begin at this detail. A semi-detached property with three previous mastic applications at the same point requires the lead to be lifted, the chase cleaned, and the joint re-bedded before the leak can be properly resolved.

A correct repair at this detail involves:

• A fresh chase 25mm into a mortar joint
• A code 4 lead apron dressed 75mm down
• A bonded membrane upstand of at least 150mm
• A trim bar at 300mm centres along the top

This detail is capable of withstanding five years without movement.

A rotten deck requires the replacement of affected boards before any membrane is applied. Bonding a new patch over wet timber risks failure within months.

We lift the patch zone and probe each board with a moisture meter, replacing any board with readings above 18%. We also inspect the joists below at their bearing ends for rot, then fix new OSB or plywood at 150mm centres.

Sound-looking felt can conceal a wet deck beneath, so the repair can only hold if the timber is addressed first.

Flat roof repair work does not carry a workmanship guarantee. A 10-year workmanship guarantee applies only to new installation work.