Thetford Roofers installs and replaces flat roofs on extensions, garages, and bay windows across Stanton and the surrounding villages.
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Flat roofing costs vary more than most homeowners expect, and understanding what drives the price up or down helps you budget properly and spot a quote that looks too good to be true. A single-ply EPDM rubber replacement on a standard garage roof typically runs from around £70 to £100 per square metre, including stripping the old felt, disposing of waste, and relaying with correct drips and upstands. A felt system using high-performance torch-on layers sits in a similar bracket. For a typical single-car garage of around 15-18 square metres, the total installed cost is usually somewhere between £1,100 and £1,900, depending on the factors below.
These are working figures based on current UK labour and material rates. They are not fixed prices, and every roof survey can reveal something that shifts the final number.
The single biggest variable is the condition of the existing deck. If the plywood or timber boarding underneath the old felt has rotted, it needs replacing before any new membrane goes down. A roofer who quotes without checking the deck is guessing. Deck replacement adds both material cost and time, often adding £200-£500 or more to a garage job if a significant area of boarding has gone soft.
Access is the next factor. A flat roof over a rear extension that backs onto a tight garden, or a bay window above a conservatory roof, can require extra time to set up safely. On some properties, scaffolding or a podium tower is needed rather than ladders, and that hire cost will appear in the quote.
Upstands and abutments add cost too. Wherever the flat roof meets a wall, a parapet, a chimney, or another roof surface, the membrane has to be dressed up and made watertight at the junction. More junctions mean more detail work, more lead or code-compliant flashing, and more time. A flat roof on a simple garage with one wall abutment is quicker to waterproof than a complex rear extension wrapping around multiple obstacles.
The membrane system you choose affects cost. EPDM rubber is a single sheet that bonds down and has very few seams, which is one reason it holds up well over time. Torch-on felt is layered, typically two or three layers, and the material cost is lower but the labour is comparable. Both are legitimate choices; the right one depends on the roof geometry and what the deck can support.
A small, straightforward roof with a clear fall to a single outlet, a deck in good condition, and easy access from a garden will cost noticeably less than a complicated job. If you are getting the work done at the same time as other roofing on the same property, the setup and access costs are shared, which can reduce the overall figure.
Catching the problem early also saves money. A failing flat roof that is caught when the membrane has lifted at one edge but the deck is still dry costs far less to sort than one that has been leaking for two winters and has softened the boarding and the joists below. A roof that drips into a garage ceiling may seem like a minor nuisance, but water sitting in a timber deck quickly spreads beyond the wet patch you can see.
Standing water on a flat roof after rain is always worth investigating. All flat roofs are designed with a slight fall - usually at least 1:80 in slope - to move water to the outlet. When water pools for more than 48 hours after rain stops, either the fall has gone (the deck has sagged or settled) or the outlet is blocked. Over time, standing water accelerates the breakdown of the membrane surface and adds weight the structure may not be designed to carry.
Blistering on the surface of a felt roof means moisture has become trapped between layers during laying, or has found its way in through a crack and is now expanding and contracting with temperature changes. Blisters are not always immediately leaking, but they are a sign the membrane is compromised and worth surveying before winter.
Cracks or splits around the edge of the roof, particularly at the drip edge or where the membrane turns up against a wall, are common entry points for water. These junctions work hard because the membrane is trying to move with thermal expansion while the wall it is bonded to stays rigid. A clean, properly dressed upstand with a chase flashing above it is what a good installation looks like at those junctions.
Damp patches on ceilings directly below a flat roof, or on walls adjacent to a flat-roofed extension, are the most obvious sign that water is getting in. The entry point on the roof surface is rarely directly above the wet patch inside - water travels along joists and vapour barriers before it finds somewhere to drip. That is why a survey matters: you are looking for the source, not just the symptom.
A proper flat roof survey looks at four things above all else:
These are the points most likely to cause a leak and the points most often skipped by a quick visual from the ground. If a quote is given without physically walking the roof and checking these details, it is not a survey - it is an estimate based on hope.
High-performance torch-on felt (also called modified bitumen) has been used reliably on domestic flat roofs for decades. A two or three-layer system, installed correctly with proper priming and edge details, performs well and is straightforward for future roofers to patch or repair. The material is widely available and the technique is well understood.
EPDM rubber is a single-layer membrane bonded with adhesive. Because it comes in large sheets with very few seams, there are fewer potential leak points. It handles thermal movement well and the surface stays flexible in cold weather. Both systems are suitable for domestic flat roofs; both rely on correct installation of the details - edges, junctions, and outlets - far more than on the membrane material itself.
As well as Stanton, we carry out flat roofing work across the surrounding area including Thetford, Brandon, Mundford, Barnham, Elveden, Croxton, Brettenham, Kilverstone, and East Wretham. If you are in a village nearby and are not sure whether we cover your postcode, call us and ask.
If your flat roof is showing any of the signs above, get a roof survey. We will walk the roof, check the deck, assess the drainage, and give you a clear breakdown of what the job involves and what it will cost before you agree to anything.
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Call any time. Calls are answered day and night and passed straight to our roofers.
