What Should Be Checked Under an Old Flat Roof Before Re-Roofing in Lawrence Hill?

Before any new roof covering goes down on a flat roof in Lawrence Hill, there is important work to be done that homeowners do not always see, but which has a real bearing on how well the finished roof performs. Once an old covering is stripped back, several things need to be checked underneath before EPDM, or any other material, is installed.

The first and most important check is the condition of the timber roof deck itself. This boarding forms the structural base that the new membrane will be bonded or dressed onto, and any softness, rot or delamination needs to be identified and addressed. On many older Lawrence Hill properties, particularly those where a flat roof has carried the same felt covering for a long time, water has often found its way into the deck gradually over the years without being visible from above, only becoming apparent once the old covering is removed.

Alongside the deck, the condition of the supporting timber joists beneath it is worth checking where accessible, particularly if significant deck deterioration is found. Water damage that has affected the boarding for an extended period can sometimes have begun to affect the structure below it too, and this is far better identified and dealt with during a re-roof than discovered later as a more serious structural issue.

The falls across the roof, meaning the slight gradient designed to direct rainwater towards outlets, should also be assessed once the deck is exposed. If the original roof was never built with adequate fall, or if the deck has sagged over time, this is the opportunity to correct it, since building the new EPDM membrane over the same inadequate falls would simply carry the drainage problem forward into the new roof.

Edge details and any junctions with walls or chimneys need checking too. These are common points of past water ingress on older flat roofs, and the timber and brickwork around them should be assessed to make sure they provide a sound, dry base for the new membrane to be properly dressed and sealed against.

Ventilation of the roof void is another consideration on some older Lawrence Hill properties, since inadequate ventilation can contribute to condensation within the roof structure over time, separate from any issue with the external covering.

Checking all of this before installing a new membrane takes a little longer than simply laying new material over the existing base, but it is the difference between a roof that performs reliably for years and one that repeats the same hidden problems under a new surface. Brunel Roofing Bristol carries out this inspection as standard on every re-roof in Lawrence Hill, and will explain clearly what is found and what, if anything, needs addressing before your new EPDM roof is installed.

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