Flat Roof Repairs · Hounslow & west London
Flat Roof Repairs In Hounslow
Is the extension roof leaking again - or still?
Repairs and replacements that deal with the deck and the falls, not just another layer on top
West London runs on flat roofs. Every terrace with a rear extension, every 1930s semi with a garage, every bay window with a lead-or-felt top, every loft conversion with a flat dormer - that's most of the housing around Hounslow carrying at least one. They're also where the trade cuts corners, because the classic flat-roof 'repair' is another layer of felt over whatever was failing underneath. We don't do that. If your flat roof leaks or ponds, we find out what the deck and the falls are doing before anything gets covered, and then fix the roof rather than redecorating it.
Free flat roof repairs survey
Pop your details in and we'll call you back to book the survey. It costs nothing, it obliges you to nothing, and if the honest verdict is that your roof needs no work, that verdict is exactly what you'll get.
10 years
Written workmanship guarantee
Free
Surveys, quotes and second opinions
Same day
Response aim for active leaks
TW5 based
Minutes from most of the patch
What you've noticed, and what it usually means
Every job starts with something a homeowner spotted. These are the ones Hounslow rings us about, matched to what our surveys tend to find behind them.
A pond that's still there two days after rain
Flat roofs aren't flat - they're built with a fall to shed water. Standing water means the fall has gone: sagging deck, failed joist, or a roof that never had enough fall to start with. Water sitting on any covering shortens its life, and freezing pond water levers seams apart from above.
Blisters and bubbles in the felt
Moisture trapped under or between layers, expanding in the sun. Each blister is a delamination - the covering separating from itself - and each one eventually cracks at the crown. A blistered roof is announcing how it will fail; the only question is which winter.
Drips at the join between extension and house
The junction where a flat roof meets the back wall is the hardest detail on the roof, and on extensions it's often where the original builder economised. Failed upstands and shortcut flashings here send water down inside the wall - it shows at the ceiling line, sometimes a room away.
A green roof you didn't plant
Moss and grass mean the surface holds water long enough for things to live in it - drainage failed a while ago. Roots then work into every seam. By this stage the question is usually what the deck underneath looks like, which is what our survey answers.
Our way with flat roof repairs
The deck gets inspected, always
A flat roof is only as good as the timber under it. We check the deck for softness and the falls with a level before quoting - because covering a rotten deck is selling you a failure with a warranty on it.
Ponding solved, not resurfaced
Where water stands we correct the reason - re-firring to restore the fall, replacing sagged deck sections - rather than laying new material into the same puddle-shaped future.
EPDM, felt or fibreglass on merit
We fit all three and will tell you which suits your roof and budget, with the trade-offs laid out. What we won't do is sell whichever one is on special this month.
Junctions done like they matter
Upstands to proper height, flashings chased into brick, drips over the gutter edge - the boring details that decide whether an extension roof lasts twenty-five years or eight.
Repairs offered when repairs will hold
A single split or a failed joint on an otherwise sound roof gets a repair price, not a replacement lecture. Plenty of flat roofs around here have years left with one well-made fix.
Guaranteed for ten years
The workmanship guarantee applies to flat work exactly as to pitched - in writing, ten years, and we're eight minutes away if you ever need to use it.
A hundred years of extensions, one recurring mistake
The flat roofs of Hounslow tell the story of how west London grew. Victorian terraces got their kitchen and bathroom additions out the back; the interwar semis came with garages and bay windows ready-roofed in felt; the last thirty years added conservatories, side returns and dormers on almost every street. Nearly all of it was roofed flat, and nearly all the failures share one cause: the fall. A flat roof needs to shed water like a very shallow hill, and building one with a proper fall takes care at the joists that extension builders in every era have skipped. The result is the west London pond - that permanent puddle in the middle of the extension roof, quietly rotting whatever sits beneath it. When we replace a roof like that, restoring the fall is the actual job. The shiny new covering is just the visible part.
"Most of the failed flat roofs we strip around Hounslow have two or three previous 'repairs' layered inside them, each one a lid on the same original fault."
From the flat roof repairs jobs on Watertight Roof Repairs Hounslow's books
Four stages, zero surprises
Tell us what you've spotted
Phone or form, plain words. 'The gutter waterfalls at the corner' or 'there's a mark spreading on the landing ceiling' is all the technical detail we need to get started.
Free survey, roof and loft both
We look from outside at height and from inside where the evidence lives. Half an hour, no charge, no obligation - and if the roof turns out to be fine, that's the report you get.
Photos, diagnosis, fixed price
You see what we found before you hear what it costs. The quote is itemised - materials, labour, access on separate lines - and the figure on it is the figure on the invoice.
Repair, tidy-up, paperwork
The work done as specified, the site left clean, completion photos sent to your phone, and the ten year written guarantee handed over. Then you forget about your roof, which is the point.
Sometimes the survey says: leave it alone
Not every worried call needs a roofer. When the honest finding is that your roof is fine - or that the real fault costs £80, not £800 - that's exactly what the report says. Free bad-news-that-isn't is how a local firm earns the next ten years of recommendations.
The guarantee is a document, not a phrase
"All work guaranteed" costs nothing to say, which is why every van in west London says it. What matters is whether anything gets written down. Work arranged through Watertight Roof Repairs Hounslow comes with a 10 year workmanship guarantee as an actual piece of paper - dated, signed, specific to your job - handed over alongside the completion photos. Materials carry their manufacturers' own cover on top, which varies by product, so your paperwork names what applies to yours instead of waving at a number.
A guarantee that long is only affordable if the repairs don't come back - so it shapes how the work is done. Failed material comes off rather than getting covered over. Replacement tiles and slates go on with fixings specified for a roof that lives under the Heathrow approach, not the minimum the 1930s got away with. Junctions get lead. And anything we find that we can't fix that day gets photographed and said out loud, because surprises kept from you now become our problem within 10 years.
Plainly: if water gets back in through work we've done, we return and put it right at no cost, for a decade. Ask any firm quoting against us to match that in writing - it's an interesting conversation to watch.
10 yrs
Workmanship, in writing
£0
Cost of a return visit under it
Insured
Public liability in place
Named
Manufacturer cover per job
Three questions that sort roofers fast
Ask these of anyone quoting for this work - including us. The firms worth hiring answer them happily; the rest change the subject.
Ask what happens to the old layers
Overlaying failed felt keeps the failure and adds weight. Any quote should say plainly whether the existing covering comes off - and if it stays, why that's sound in your specific case rather than just cheaper.
Ask how the fall is being checked
The right answer involves a level and a look at the deck, before the price is fixed. A firm that quotes a flat roof from the pavement has priced the covering, not the roof.
Ask for the guarantee and the fixer
Membrane manufacturers offer long product warranties, but the product is rarely what fails - the workmanship at the edges is. You want both covered in writing, and the workmanship is the one to read closely.
EPDM rubber versus felt: the west London flat roof question
Both can be excellent and both can be terrible - the installer decides which. Here's the fair comparison for a typical extension or garage roof around Hounslow.
| Comparison point | EPDM rubber membrane | Modern torch-on felt |
|---|---|---|
| Realistic lifespan | 40-50 years fitted well - often one sheet, no seams to fail. | 20-30 years for good three-layer work; the budget version much less. |
| Weak point | The perimeter detailing and anything glued in a hurry. | Seams and edge terminations, especially where wind can get a grip. |
| Repairs later | Patches bond well; punctures are rare and fixable. | Patchable, but each patch shortens the distance to replacement. |
| Looks | Matt black sheet - tidy, plain, best where the roof isn't overlooked. | Mineral finishes look traditional and hide patches better from above. |
| Cost | More per square metre up front, less per year of service. | Cheaper on day one, which is why landlords love it. |
| Our steer | First choice for most extensions and garages we replace. | Right where budget rules or a period look matters from above. |
When the flat roof is fine and the gutter is the villain
A satisfying number of 'flat roof leaks' we survey are nothing of the kind - the covering is sound and the water is arriving from a blocked outlet, a failed drip edge or a gutter tipping water back under the eaves. Before you budget for a new roof, it's worth ruling out the cheap suspect.
See our guttering work
What flat roof repairs costs around here
Patch repairs on sound flat roofs sit in the low hundreds. Full replacement is priced by area and deck condition: a garage roof typically lands in the low four figures, a larger extension more, with EPDM costing somewhat above felt and outlasting it comfortably. If the deck needs work you'll know before the quote is signed, never as a surprise afterwards - the survey that establishes it is free.
See the full cost guideFlat Roof Repairs questions, answered straight
Can you just patch my flat roof rather than replace it?
Often, yes - and when a patch will hold we quote a patch. A single split, a failed joint or an isolated blister on a roof with life left in it is a small job. What we won't do is patch a roof whose deck is soft or whose covering has failed generally, because you'd be paying us for a postponement dressed as a repair. The survey tells us which conversation to have, and it's free either way.
How do I know if my flat roof deck has rotted?
Signs from below: staining or sagging on the garage or extension ceiling, a musty smell, dark streaks at fixing points. Signs from above: springiness underfoot, visible dips, ponds that grow year on year. Any of those wants a proper look. We check decks as part of every flat roof survey - it takes minutes and changes everything about the right fix.
Do I need planning permission to replace a flat roof in Hounslow?
For like-for-like replacement on a house, almost never - it's repair and maintenance. It only gets interesting if you're changing the roof's height or form, or the property sits in one of the borough's conservation areas like The Butts in Brentford or Old Isleworth, where materials visible from the street matter. Flats and maisonettes have different rules than houses. We'll flag it honestly if your job touches any of this - for most Hounslow extensions and garages it doesn't.
Why does my flat roof leak in winter but not summer?
Two usual reasons. Small splits and failed seams close up in warm weather as the material expands, then open in the cold exactly when the rain arrives. And some winter 'leaks' are actually condensation - a cold deck with poor ventilation soaking itself from the inside. They need opposite fixes, which is why diagnosing before repairing isn't optional. We tell you which yours is with evidence.
How long does a flat roof replacement take?
A garage in a day or two; a typical extension two to three, weather permitting - stripping, deck repairs, insulation where specified, new covering and edge details. We don't open up more roof than we can make watertight the same day, so your kitchen isn't gambling on the forecast overnight.
Related reading: Roof Leak Repairs ·Guttering
Where we do this work
Flat Roof Repairs across Hounslow and the boroughs that surround it - Isleworth, Brentford and Feltham on our doorstep, Twickenham and Richmond over the A316, Ealing to the north, and Hayes and Uxbridge out along the Hillingdon side.
What the patch says about us
Homeowners from Cranford to Hayes on how their jobs actually went.
"Woke up to tiles all over the front garden and not a breath of wind - couldn't work it out. They came the same morning, made it safe, and were the ones who told us it looked like vortex damage from the planes and that Heathrow has a scheme for exactly this. Helped us photograph everything properly for the claim. Could easily have just charged us for a repair and said nothing. That honesty is why I'm writing this."
"Our loft conversion started leaking around the dormer two winters after the conversion company vanished. Two roofers quoted big money to strip the whole dormer roof. These guys traced it to one badly-lapped flashing on the cheek, showed me the photo, fixed it in half a day. It's been through every storm since bone dry. The difference was they looked before they priced."
"Called them expecting to be told the roof needed doing - the house is 1936 and the ridge had been dropping mortar crumbs for a while. Survey verdict: re-bed the ridge, replace five tiles, and the rest is good for years yet. They even marked two tiles to keep an eye on. Quote was a fifth of what I'd braced for. When the roof does eventually need doing, they've earned that job."
"Water started coming through the back bedroom ceiling at 7am on a Sunday. Rang around - one lot quoted a £180 call-out before they'd even start. This firm answered, talked me through switching off the lights circuit and where to put the buckets, and was here by half nine. No weekend premium, made it dry, came back Tuesday and did the proper repair for a very fair price. Kept every promise they made on the phone."
"Had the fascias, soffits and gutters done on our terrace. What sold me was the survey - they pushed a screwdriver into the old boards to show me which were actually rotten and which were fine, then quoted to replace only what needed it. Other quotes were for capping over the lot, which they explained the problem with. Work was neat, gutters run properly for the first time in years, and the guarantee arrived as a proper document."
Had us out to your roof?
Two minutes writing a review does more for a small local firm than any advert we could buy - and it helps the next west London household with a drip find someone straight.
The free flat roof repairs survey is where it starts
Half an hour of our time, none of your money, and you'll know what's actually happening up there - with photographs, a plain-English verdict and a fixed price if anything needs doing. If nothing does, you'll know that too, in writing.