Felt Roofing Hampshire

Blisters forming on the felt surface indicate that moisture or air has become trapped between the bitumen layers. As temperatures rise, the blisters expand and can rupture, exposing the layers beneath to water ingress.

A well-maintained felt roof generally lasts between 15 and 25 years. When blistering appears, the covering has most likely reached the end of its serviceable life and requires full replacement rather than patch repairs.

Seam edges that curl and allow light through indicate that the bitumen adhesive has failed and the laps are no longer bonded. Properly sealed laps are essential to the roof’s longevity.

When seams split or curl, replacement is necessary, as water will penetrate between the layers. The 100mm side laps and 150mm end laps must be fused with hot bitumen to prevent this failure.

When mineral chippings are lost from the surface, the capsheet is exposed to direct UV radiation, which accelerates degradation. The mineral finish protects the layers beneath from ultraviolet exposure.

Chippings washing away indicates that the covering has reached the end of its useful life. Without this protection, the bitumen becomes brittle and the roof’s lifespan falls significantly short of the standard 15 to 25 years.

Brown stains on ceilings below the roof indicate active water ingress through the felt covering. Water penetrates through failed laps or ruptured blisters and tracks down through the deck into the room beneath.

Soft, spongy areas underfoot may also be present, pointing to water damage in the deck timbers. A deck inspection using a moisture meter, screwdriver and deflection test will reveal the extent of any damage before installation begins.

Soft, spongy areas underfoot indicate possible water damage to the deck timbers beneath the felt. A dry, secure deck is essential for durability, and any compromised boards must be replaced before the new felt is installed.

The survey will establish the most suitable specification for your project, including checking for soft boards and confirming that the deck surface is clean and free from debris. Our process requires removing the existing covering and inspecting the deck in full before the three layers are applied.

The old covering is removed in full and any compromised boards are replaced before work proceeds. Thorough deck preparation ensures the surface is dry and secure, which is essential for the longevity of the new felt roof.

A comprehensive inspection at this stage reveals potential issues beneath the surface, allowing structural concerns to be addressed before installation. The deck must be clean and free from dust, grit and loose material.

Bitumen primer is applied to the prepared deck and allowed to cure fully before the underlay is installed. Correct primer application ensures the first layer bonds reliably to the substrate.

Ideal installation conditions are temperatures between 5°C and 25°C, with no rain forecast for 24 hours. Cold temperatures can make bitumen brittle, while excessive heat can affect adhesives.

A vented underlay is bonded to the deck to prevent direct contact between the felt and the timber. This layer is typically 1500gsm vented or polyester material.

The vented underlay prevents moisture from becoming trapped and allows the deck to breathe. Each layer is permanently fused using a torch flame, creating a seamless waterproof barrier.

An SBS-modified intermediate layer is torched on with precise laps, adding reinforcement to the roof system. This layer is typically 2000gsm SBS-modified polyester.

Each layer contributes to the overall strength of the roof, with the intermediate layer providing additional durability. Properly staggered laps prevent misalignment and ensure stability across varying weather conditions.

The roof is finished with a mineral capsheet, typically 4000gsm mineral-faced SBS, with staggered laps for maximum protection. The capsheet provides UV protection and weather resistance for the layers beneath.

Properly sealed laps and effective drainage are essential for maximising the roof’s lifespan. All new felt roof installations by C J Roofing & Renewables Ltd are backed by a 10-year workmanship guarantee, giving you confidence in 15 to 25 years of reliable service.

Ideal installation conditions are temperatures between 5°C and 25°C, with no rain forecast for 24 hours. Cold temperatures cause bitumen to become brittle, while excessive heat can affect adhesives. Humidity and wind conditions are also significant factors: high moisture levels can lead to vapour becoming trapped, while strong winds can disrupt the installation process.

Sealing uses 100mm side laps and 150mm end laps, each fused with hot bitumen. Properly staggered laps prevent misalignment and ensure stability across varying conditions. Edge details are specific to each location, with particular techniques applied to prevent wind lift and ensure long-term durability.

A minimum design slope of 1:40 is required to prevent water from ponding on the surface. Correct slope construction ensures effective drainage and extends the service life of the roof. Our process includes forming adequate falls and installing appropriate drainage systems to maintain the roof’s integrity over time.

Felt meets abutting structures using 150mm upstands and lead flashings. Properly dressed laps ensure a secure seal and protect against water ingress at these junctions. Precise techniques are used to ensure all penetrations and joints are effectively sealed, providing durable protection at every transition point.

A warm felt roof incorporates a vapour control layer together with rigid insulation. This construction minimises condensation risks and improves energy efficiency. Ventilation requirements differ between warm-roof and cold-roof designs, and our approach is tailored to the specific requirements of each project.