If your flat roof in Lavenham has started leaking, what you do in the hours and days before a roofer arrives can make a real difference to how much damage results.
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Flat roofs on garages, extensions, dormers and bay windows fail for a handful of predictable reasons. Felt membranes blister and crack as they age. Flashings where the roof meets a wall separate from the masonry. Drainage outlets block and water ponds until it finds a way through. EPDM rubber membranes are more resilient, but seams and bonded edges can lift if the original installation was not thorough or if the deck beneath has moved.
Understanding the likely source of the problem helps you protect the right things inside while you wait. A leak appearing at the ceiling in the middle of a room usually means water is tracking along a joist from a different entry point. A leak appearing at a wall junction almost always points to a failed flashing rather than the membrane itself.
The priority is to limit water damage to the structure and the contents beneath the leak, not to fix the roof yourself.
This is the part of the page most homeowners need most. The impulse to do something immediate is understandable, but several common responses to a flat roof leak make the job harder and more expensive to fix properly.
Do not apply roof sealant, bitumen paint or waterproofing tape to the membrane. These products are sold as emergency fixes and they are genuinely useful when applied correctly as part of a planned repair. Applied hurriedly to a wet membrane in variable weather, they do not bond reliably and they contaminate the area around the failure. A roofer who arrives to find the site of the leak covered in mastic or lap tape now has to remove that before they can make a proper repair. This adds time and cost.
Do not lay a tarpaulin directly on the membrane and walk around on it. A tarpaulin can reduce water ingress temporarily if it is laid carefully and secured at the edges without damaging the membrane or the flashings. Walking around on a flat roof, especially an older felt one, risks cracking a surface that is already under stress. If you can lay a board first and step on that, you reduce the risk. Better still, leave the roof itself alone.
Do not attempt to re-seal a lifted flashing with mastic yourself. Pointing over a gap with sealant from a tube is a temporary measure at best. Flashings need to be properly dressed back into the masonry, and the lap into the membrane needs to be correctly bonded. A mastic bead on top traps moisture behind it and speeds deterioration of the joint.
Do not wait too long. A small leak left unattended for several weeks will wet the deck beneath the membrane. Once the timber deck starts to absorb water, what might have been a straightforward membrane repair becomes a partial or full deck replacement as well. A repair job that might have cost £200 to £400 can become a replacement job costing several times that if the deck is allowed to become saturated.
In genuinely heavy or persistent rain, a carefully laid tarpaulin secured firmly at the edges without walking repeatedly on the roof surface can be a reasonable short-term measure. Use fixings at the edges rather than weights on the membrane, avoid walking on the surface more than once, and remove it as soon as the roofer arrives. A tarpaulin that is left in place for more than a few days traps moisture and heat, which does its own damage to an older felt surface.
When the roofer arrives, the most helpful thing you can do is show them where the water has appeared inside, when you first noticed it, and whether it is linked to specific weather conditions such as heavy rain versus driving wind. Wind-driven rain can enter at completely different points from a standard rainfall leak. If the leak only appears when rain is blowing from a particular direction, it points strongly to a flashing failure rather than a membrane failure.
If you have photographs of the ceiling stain or the roof surface, share them. The roofer will still inspect everything themselves, but context speeds up the process.
Once the immediate situation is managed, you will be making a decision about repair or replacement. For a roof in Lavenham or nearby areas, the typical options are the same as anywhere in this part of Suffolk: a targeted repair to a membrane or flashing that is otherwise sound, or a full strip and relay using either mineral felt or EPDM rubber membrane.
A targeted repair on a sound roof typically costs between £150 and £400. A full flat roof replacement on a standard garage or extension runs from approximately £50 to £100 per square metre for materials and labour, before any deck repairs that may be needed once the old material is stripped back. For an average garage roof of around 15 to 18 square metres, that puts the replacement cost in the range of £750 to £1,800, varying with material choice and access.
EPDM rubber is the longer-lasting option of the two main materials. It handles temperature fluctuation well, has fewer seams than a felt system, and typically lasts 20 years or more when correctly installed. Mineral felt in a quality two- or three-layer torch-on system remains a sound choice for garages and smaller extensions and costs less upfront. The right choice depends on the structure, the budget and how long you plan to be in the property.
If you have a leak and you are waiting for a proper repair, call Bury St Edmunds Roofers for a survey. We cover Lavenham and the surrounding area from our base in Bury St Edmunds. We will inspect the membrane, the deck and the flashings, and give you a straight quote for what the roof actually needs. Call us to book a visit.
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Call any time. Calls are answered day and night and passed straight to our roofers.
