Flat Roof Replacement Beneath Timber Decking in Leamington Spa

A roof does not always look like a roof. At this property on Bertie Terrace in Leamington Spa, the waterproof flat roof covering sat underneath an external timber deck, meaning the roofing system itself was largely hidden from view during everyday use.

Roof Maintenance Leamington was brought in to renew the ageing flat roof while preserving the usable decked area above it. The existing timber decking was carefully lifted, the old felt roofing system removed, the roof was newly boarded and a RESITRIX EPDM flat roofing system installed.

Once the new waterproof roof was complete, the existing decking was reinstated, with new timber supplied where sections had deteriorated.

This project is a good example of why flat roof maintenance is not always straightforward. The roof covering was positioned beneath timber decking, which meant the waterproof layer could not simply be accessed and replaced from above without first removing the deck.

The photographs show the existing deck covering the full roof area immediately outside the property. When flat roofing sits beneath decking, both elements need to be considered separately.

The decking provides the surface people see and walk on, but underneath it sits the roofing system responsible for keeping the building weatherproof. If that waterproof layer reaches the end of its serviceable life, replacing only the visible decking does nothing to address the roof beneath it.

The first stage of the project was therefore to lift the existing timber decking. Rather than automatically replacing everything, the decking was removed carefully so that suitable sections could later be reused.

This provided access to the underlying flat roof structure while also allowing the condition of the timber to be inspected. Once the deck boards had been removed, the construction beneath became visible and the roofing work could begin properly.

Beneath the decking was an older felt flat roofing system. Flat roofing materials do not last indefinitely. Over time, repeated exposure to temperature changes, moisture and general weathering can cause older roof coverings to deteriorate.

Once a flat roof has reached the point where its covering requires replacement, repeatedly repairing isolated sections can become less effective than renewing the roofing system properly. At Bertie Terrace, the existing felt roof was removed so the new roof could be installed onto a suitable renewed surface.

Before the new waterproof membrane was installed, the roof was newly boarded. This is an important stage in any flat roof replacement because the waterproof roof covering depends on the structure underneath it.

Installing a new membrane over unsuitable or deteriorated boarding risks carrying problems from the old roof into the new installation. The new boards created a clean and consistent substrate ready for the new waterproofing system.

This also gave the team an opportunity to properly form the roof area around the doorway, perimeter walls and surrounding roof details.

Once the new roof deck was prepared, a RESITRIX EPDM roofing system was installed. EPDM is a synthetic rubber roofing material widely used on flat and low-pitched roofs because it creates a durable waterproof membrane across the roof surface.

For this project, that waterproofing was particularly important because the finished roof would once again sit underneath timber decking. Once the decking was reinstated, accessing the roof membrane would naturally become more involved.

Installing a suitable long-term flat roofing system beneath it was therefore a key part of the project. The completed photographs show the dark EPDM membrane extending across the roof area, with careful detailing around the perimeter.

A flat roof is not simply a waterproof sheet laid across a horizontal surface. Some of the most important areas occur where the roof meets surrounding walls, door thresholds, parapets, adjoining pitched roof sections, drainage points and perimeter edges.

These details are particularly important because they are where rainwater can find its way into a building if the roof covering is not correctly formed.

At Bertie Terrace, the completed roofing system was carefully detailed around the walls and adjoining structures before the timber deck was put back. The waterproof membrane continues into these perimeter areas rather than stopping abruptly at the main roof surface.

Once the new flat roof was complete, the outdoor area could be returned to its original purpose. The existing timber decking was relaid over the new roofing system.

Where individual sections of the old decking had become rotten or were no longer suitable for reuse, replacement timber was supplied. This approach meant serviceable materials did not need to be unnecessarily discarded while damaged areas could still be renewed.

The result was a functioning decked area above a completely renewed flat roofing system.

Decked roof areas are a clever way of creating usable outdoor space, particularly on properties where conventional garden or balcony space is limited. But the arrangement also means the decking and roof beneath it need to work together.

The waterproof roof should not be treated simply as the floor beneath the deck. Its primary job remains protecting the property from rainwater. That means the roof covering, drainage, edges and surrounding details all need to be correctly installed before the deck is reinstated above them.

It is also important that any work carried out to the decking avoids unnecessarily damaging the waterproof membrane underneath.

One difficulty with decked flat roofs is that the roof covering itself is often hidden. That means homeowners may notice problems inside the property before they can see anything obviously wrong with the roof surface.

Possible warning signs can include damp patches, staining, unexplained moisture, deterioration around thresholds or walls, persistent leaks after rain or visible deterioration when sections of decking are lifted.

The presence of decking does not necessarily cause flat roof problems, but it can make the waterproof covering harder to inspect. If there is concern about the roof beneath an existing deck, accessing and assessing the actual roof covering is usually the sensible starting point.

Roof Maintenance Leamington carries out flat roof repairs, flat roof replacement, EPDM roofing and roof maintenance throughout Leamington Spa and the surrounding Warwickshire area.

Projects involving decking require additional care because the visible outdoor surface is only one part of the construction. At Bertie Terrace, lifting and retaining the existing decking allowed the ageing felt roof beneath it to be completely renewed with new boarding and a modern RESITRIX EPDM roofing system before the usable outdoor space was reinstated.

The finished deck may look broadly the same from above. Underneath it, however, the roof protecting the property is entirely renewed.