If your flat roof in Chippenham is showing signs of trouble, catching the problem early can save you thousands compared to dealing with structural damage caused by prolonged water ingress.
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Flat roofs are common on extensions, garages, outbuildings, and single-storey rear additions. They use a shallower pitch than a traditional tiled roof, which means drainage relies entirely on the condition of the surface membrane and the outlets built into it. Newmarket Roofers designs and installs flat roofs for properties in Chippenham and the surrounding villages, using EPDM rubber membranes and modern torch-on felt systems.
A well-installed flat roof will perform reliably for many years. The issues arise when materials age, when the original installation cut corners, or when small problems go unattended for a season or two longer than they should.
The earlier you spot trouble on a flat roof, the simpler and cheaper the fix tends to be. Below are the signs that something needs attention, and what is typically causing each one.
Water stains on a ceiling directly below a flat roof almost always mean the membrane has failed somewhere. The tricky part is that water travels before it drops, so the wet patch on the ceiling may not sit directly below the entry point. A proper inspection of the full roof surface is needed, not just a look at the area above the stain.
A small amount of water sitting on a flat roof after rain is normal. If it has not drained within 48 hours, you have either a blocked outlet or a surface that has deflected over time. Ponding water accelerates the breakdown of felt membranes in particular, because UV light and freeze-thaw cycles work on it from above while the weight stresses the deck below.
Blistering in a felt roof is caused by trapped moisture vapour expanding under heat. Once the surface blisters, the membrane is compromised. Rain can work into any crack or split that forms at the edge of a blister. This is a sign the roof is towards the end of its serviceable life and a full replacement is worth considering rather than repeated patching.
The perimeter of a flat roof takes the most stress. Felt contracts in cold weather and expands in heat, and over years this movement works the material away from the fascia, parapet wall or upstand it is dressed against. When the edge lifts, rainwater can get underneath the membrane. Check the drip edge and any lead or code-3 flashing where the roof meets a wall.
On an older felt roof, surface cracking is a sign the bitumen has dried out. Traditional mineral-finish felt has a lifespan of roughly 10 to 15 years before UV degradation makes it brittle. Once cracks form, they widen with each frost. A split is an active leak waiting for the next rainfall.
A flat roof deck that feels spongy underfoot usually means the plywood or timber deck beneath the membrane has taken on moisture. Wet timber rots, and a rotten deck cannot hold fixings or support a new membrane without first being replaced. Ignoring this stage makes the eventual job significantly more expensive.
Where a flat roof meets a chimney, a wall, or a vertical surface, lead or code-3 metal flashing seals the joint. Flashing is bedded into mortar joints and dressed down over the upstand. When the mortar cracks, or the flashing is lifted by frost or wind, water runs directly behind the membrane. This is one of the most common causes of leaks on otherwise sound roofs.
Understanding what causes failure helps you ask better questions when getting quotes and makes it easier to judge whether a repair or a full replacement is the right call.
A localised repair - sealing a split, re-dressing a flashing, or clearing a blocked outlet - is appropriate when the rest of the roof is in sound condition and the membrane is not yet at the end of its life. If a roof has been repaired two or three times in five years, or if the deck is soft and wet, a full strip and replacement is the more cost-effective route. Piling more felt or sealant onto a failing substrate only delays the inevitable.
When a full replacement is needed, the deck is stripped back, any rotten boarding is cut out and replaced, the insulation is assessed, and a new membrane is installed. EPDM rubber is a popular choice for replacements because it is installed as a single sheet with very few joins, which reduces the number of potential leak points. Torch-on felt systems using modern polyester-reinforced felt are also durable and widely used.
Before any roofer starts work on your flat roof, it is worth asking a few direct questions. Ask them to show you the deck condition once the old felt is stripped - if they cannot explain what they found and why, that is a concern. Ask what falls are being built into the new roof and how drainage is being handled. Ask what membrane system they are using and what the manufacturer states about its expected lifespan. A good roofer will answer all of these without hesitation.
Call us to arrange a flat roof survey and we will give you a straight assessment of what the roof needs.
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Call any time. Calls are answered day and night and passed straight to our roofers.
