Service
Flat Roof Repairs andReplacement in BathDetailed to Stay Dry
Flat roofs fail at the edges, not the middle. We fix the detail that is actually letting water in, and tell you straight whether a repair or a new covering gives you better value.
22 years on Bath roofs · Fixed price before work starts · Fully insured
22 years' experience
Established 2004
Fixed-price quotes
Agreed in writing, not a day rate
£1,000,000 public liability
Insured for your protection
Emergency call-out
Available when a roof cannot wait
Overview
What Flat Roofing Work Covers
Flat roofing covers the low-pitch roofs over extensions, garages, dormers, porches, bay windows and outbuildings. These roofs are not truly flat: they are laid to a fall so water leaves rather than sits, and the majority of failures we attend are caused by that fall being wrong, blocked or lost over time.
Work ranges from localised repairs where the deck is sound and the failure is isolated, through to full replacement where the covering has reached the end of its life. In both cases the critical work is at the perimeter: upstands against walls, drip edges, outlets, and the junction where the flat roof meets a pitched roof or a wall.
We assess whether a repair is genuinely worthwhile before quoting one. Coating over a tired, blistered covering is the cheapest thing to sell and the most likely thing to fail, so we do not lead with it.
Who this work is for
- Homeowners with a leaking or ponding extension, garage or dormer roof
- Anyone with blistering, splitting or bubbled felt on a flat roof
- Properties where water is tracking down an internal wall below a flat roof junction
- Owners planning to convert a garage or extension who need the roof sound first
- Anyone who has had a flat roof coated repeatedly and is still getting water in
What's included
- Flat roof leak repairs on garages, extensions and dormers
- Full flat roof replacement where the covering has failed
- Correct falls, upstands and outlet detailing
- Advice on repair versus replacement, given straight
What happens if it is left
The Cost of Waiting Another Winter
A flat roof leak reaches the inside faster than a pitched roof leak. There is no loft void, no felt layer beneath and no distance for the water to travel: it comes straight through the deck into the ceiling below, so damage shows up in plaster, paint and joinery within days.
Ponding is the quiet killer. Standing water accelerates UV and freeze-thaw damage, finds any weakness at a joint and adds weight to a deck that was never designed to carry it. A blocked outlet or a slumped fall turns a covering with years left into a covering with months left.
Once water reaches the deck, the job changes. Wet chipboard or OSB swells and loses strength, joist ends soften and the whole roof needs re-decking, which typically costs considerably more than the re-covering that would have prevented it. The same is true where water tracks into the wall below a failed upstand and reappears as internal damp on a room that has nothing to do with the roof.
Common mistakes we are called in to undo
- Painting liquid coating over blistered, damp felt and hoping it seals
- Leaving outlets and gutters blocked so water ponds all winter
- Terminating an upstand too low, or with mastic instead of a proper flashing
- Fitting a new covering over a soft, water-damaged deck
- Ignoring the first small ceiling stain because the roof 'only leaks in heavy rain'
Our process
How the Job Runs, Start to Finish
The same sequence on every job, so you always know what happens next and what it costs before it happens.
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Step 1
Inspection
We check the covering, falls, outlets, upstands, drips and: critically, whether the deck beneath is still sound underfoot.
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Step 2
Diagnosis
We identify whether the failure is localised or systemic, and give you a straight answer on repair versus replacement.
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Step 3
Fixed written price
The quote covers strip, deck repair if needed, covering, insulation where applicable and all perimeter detailing.
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Step 4
Installation
Old covering stripped, deck made good, falls corrected, new covering laid and dressed into upstands, drips and outlets.
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Step 5
Water test and handover
Outlets checked for flow, perimeter details inspected, debris cleared and the finished roof shown to you.
What you get
Why This Work Is Worth Doing Properly
The detail is right
Upstands, drips and outlets are formed properly, which is where flat roofs actually leak.
Water leaves the roof
Correct falls and clear outlets end ponding, which is what shortens the life of every flat covering.
Honest repair-or-replace advice
We will tell you when a repair is a false economy rather than quote the easier job.
Deck problems caught early
A soft deck is identified at inspection, not discovered halfway through and used to inflate the bill.
Fixed price
One written figure agreed before the covering comes off.
Room below stays usable
A dry extension or converted garage stops eating decoration and stops smelling damp.
In detail
Flat roofs: Materials, Methods and Variations
The specifics that decide whether the work lasts, written out so you can judge any quote you receive, including ours.
Coverings and Where Each Works
Flat roof coverings are not interchangeable. The right one depends on the size and shape of the roof, whether it is walked on, how it meets adjoining walls and roofs, and how much detail work is involved.
- Torch-on felt systems, robust, well proven, good for garages and extensions
- Single-ply membranes, few joints, suited to larger plane areas
- Liquid systems, useful around complex penetrations and awkward detailing
- Lead and hybrid details, for junctions where a flat roof meets a pitched roof or parapet
Falls, Outlets and Perimeter Detailing
Every flat roof needs somewhere for water to go and a route to get there. Falls are created by firrings or tapered insulation and must be continuous: a fall that stops short of the outlet just moves the puddle. Outlets must be sized and sited so leaves and moss do not immediately choke them, and fitted with a leaf guard where trees overhang.
At the edges, a drip must throw water clear into the gutter rather than let it run back under the covering, and an upstand against a wall must rise high enough and be capped with a proper flashing chased into the masonry. Mastic-only terminations are the most common defect we find and the first thing we correct.
Decks, Insulation and Condensation
A flat roof is a system: deck, vapour control, insulation, covering. Get the order wrong and the roof fails from the inside through condensation even when the covering is sound. Warm-deck construction: insulation above the deck, is the current standard for extensions and conversions because it keeps the deck warm and moves the dew point above the timber.
Where a deck is water-damaged we replace the affected boards rather than covering them. Where a garage or extension is being converted to living space, insulation and vapour control are specified as part of the roof rather than left to the plasterer.
Garages, Dormers and Extensions
Garage roofs are usually simple planes with few penetrations, so the work concentrates on falls, edges and the abutment with the house. Extension roofs bring more junctions: rooflights, soil pipes, the wall of the house, and each one is a potential leak. Dormer roofs are the most detail-heavy of all: small plane, tall cheeks, junctions with the main pitched covering and lead soakers where they meet.
Long-term dormer and parapet junctions are best formed in lead rather than covered in membrane, and we detail them that way.
Questions
Cost, Timescales and Guarantees
The questions we are asked most often, answered straight.
Can you repair a flat roof rather than replace it?
Often, yes: if the deck is sound and the failure is localised. We will tell you honestly which option gives you better value rather than defaulting to the bigger job.
How much does a flat roof cost in Bath?
It depends on area, covering, deck condition, insulation and access. We inspect first and give a fixed written price covering all of it.
How long does a flat roof last?
Life depends on the system, the quality of the detailing and whether water drains away. A correctly laid covering with proper falls and clear outlets substantially outlives one that ponds.
Why is there water sitting on my flat roof?
Either the fall is insufficient or has slumped, or the outlet is blocked. Both are fixable, and both shorten the covering's life if left.
How long does the work take?
Most domestic garage and extension roofs are completed in a small number of days, weather permitting. We confirm a realistic timescale with the quote.
Can you insulate the roof while replacing it?
Yes. If the space below is or will be habitable, we specify warm-deck insulation and vapour control as part of the build-up.
Do you do emergency flat roof repairs?
Emergency call-out is available where a roof cannot wait. We make the roof safe and watertight first, then carry out the permanent repair properly.
My flat roof has been coated twice and still leaks: why?
Almost always because the failure is at an upstand, drip or outlet rather than in the field of the roof. Coating the middle does nothing for a defect at the edge.
Which areas do you cover?
Bath, Bristol, Keynsham, Saltford, Bradford-on-Avon, Trowbridge, Frome, Radstock and Midsomer Norton.
Related roofing services
- LeadworkProperly formed lead flashings, valleys and soakers: the detail that decides whether a roof leaks.
- Roof repairsLeaks traced, slipped tiles reset and weak areas made watertight, repaired properly rather than patched.
- Gutters, fascias & soffitsClearing, repair and replacement of rainwater goods so water leaves the building, not runs down it.
- All roofing servicesEvery service we carry out across Bath and Bristol.
Get a Fixed Price for Flat roofs in Bath
Inspection first, written fixed price second, no work started until you have agreed it. 22 years' experience, £1,000,000 public liability. Call Luke Watts on 07735 894962 or send the details and we will arrange a look at the roof.