Flat roofs on extensions, garages and outbuildings need the right materials and proper drainage to last. We repair and replace felt and EPDM rubber flat roofs across Thetford and the surrounding villages, fixing leaks, pooling water and failed joints properly.
Call any time. Calls are answered day and night and passed straight to our roofers.
Flat roofs are found on everything from bay window returns to modern single-storey extensions, garage roofs and outbuilding covers. They work well when they are laid correctly with the right fall and watertight detailing at every edge and junction. When those things are not right, water finds a way in quickly, and the damage to the structure underneath can build up long before a leak shows on the ceiling inside.
We work on flat roofs throughout Thetford and the nearby villages. Whether it is a straightforward repair to a split felt or a full replacement with a modern EPDM rubber membrane, we assess the roof properly before recommending any work.
A flat roof is not truly flat. It needs a fall, typically around 1 in 80, so that rainwater drains towards the outlets rather than sitting on the surface. Getting the fall right matters as much as choosing the right membrane. Where water has been sitting, deck boards can rot, and those boards need replacing before any new covering goes on top.
The two systems we use most on flat roofs are traditional built-up felt and EPDM rubber membrane. Felt is a proven material that has been used for decades and, when laid in the correct number of layers with capsheet finishing, performs well. EPDM is a single-ply rubber sheet that handles expansion and contraction better than felt and is less prone to splitting at joints and corners. The choice depends on the roof size, its existing structure and your budget.
The work itself involves stripping back the old covering, inspecting the deck beneath, repairing or replacing any damaged timber, and laying the new membrane with attention to three critical areas:
Standing water is the single biggest sign that something is wrong. If water is still sitting on the roof 48 hours after rain, either the fall is insufficient or an outlet is blocked or has dropped. Left alone, standing water accelerates the breakdown of felt, adds weight to the deck and encourages moss and algae growth that speeds up surface deterioration further.
Blistering is another common problem, particularly on older felt roofs. Blisters form when moisture trapped between layers of felt heats up and expands. A small blister may be stable for a season, but once it breaks open the roof is exposed. On older properties, the original felt is often past its useful life and patching repeatedly becomes poor value compared with a full replacement.
Joint and seam failures are also frequent on felt roofs. Cold-applied felt and DIY patch repairs often fail at the overlaps because the bond was never strong enough to begin with. Torch-on felt, applied with heat to fuse the layers, gives a far more reliable joint. EPDM avoids the problem almost entirely because it is laid as a single sheet with very few joins.
Frost can lift poorly bonded upstands away from walls during a cold winter, leaving a gap that channels water straight into the building. Any wall junction that looks like it has pulled away or cracked at the top needs attention before autumn rain sets in.
A flat roof is a low-pitch structure that holds water, so any weakness in the installation is tested every time it rains. Poor detailing at edges and upstands is the cause of most flat roof leaks. Getting onto a flat roof safely also requires proper access - roof ladders, edge protection and safe working practices that are not optional on a two-storey extension roof.
There is also a materials question. Trade-grade EPDM and torch-on capsheet are not the same products available from a builders merchant. Using the correct specification material for the roof size and exposure makes a real difference to how long the finished job holds up. A well-specified and properly laid flat roof covering should perform reliably for many years without needing attention.
When we visit, we check the roof in a logical order rather than just looking at the obvious wet patch. We check the outlets are clear and draining freely, measure the fall across the deck, inspect all edge trim and wall upstands, and look at the surface condition. This tells us whether the roof needs a targeted repair or whether the existing covering has deteriorated to the point where a full replacement is the only sound option.
We will tell you what we find and what the options are before any work starts. If a repair will last, we say so. If the deck or covering is in poor enough shape that a repair is short-term money, we will explain why. On larger jobs, we can usually give you a realistic timeline before we start so you know when the roof will be watertight again.
Flat roof replacement costs in Thetford depend on the system chosen, the condition of the existing deck and the complexity of the detailing. A standard garage roof of around 20-25 square metres would usually fall in the range of £1,500 to £2,800 for a full replacement. EPDM tends to cost a little more than felt in materials but requires less labour on straightforward installations, so the overall price difference is often modest. Repair costs vary considerably depending on what has failed, but a localised repair to a joint or upstand typically runs from £150 to £400.
A flat roof in Thetford laid to the correct fall with properly detailed edge trims and wall upstands, using trade-grade felt or EPDM membrane, should remain watertight and require no major intervention for a considerable number of years under normal conditions.
If you have noticed a damp patch on a ceiling below a flat roof, or you can see standing water, split felt or a pulled-away upstand, the right move is to have it looked at before the deck gets involved. Call us to arrange a flat roof survey in Thetford or any of the surrounding villages and we will tell you exactly what is going on and what it will take to put it right.
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Call any time. Calls are answered day and night and passed straight to our roofers.
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