Flat Roofing Bournemouth | Repairs, Re-covers & New Roofs

Flat roofs in Bournemouth

Flat roof repairs, re-covers and replacements in Bournemouth

Bournemouth Roofing & Building repairs, re-covers and replaces flat roofs across Bournemouth: garages, rear extensions, dormers, bays, balconies and the roofs of blocks of flats. We lift a corner and stand on the deck before we price anything, because the boards decide whether you need a repair, a re-cover or a new roof. The site visit and the written itemised quote are free.

If water is coming through a flat roof right now, ring 07435 839745 and skip the form. Tell us what sits under the wet patch.

Flat roof trouble shows up as a split garage roof, a brown patch in an extension ceiling, a dormer cheek staining a bedroom wall, or two quotes for one roof where one is half the other. Tiled and slated slopes sit with our roofing services, and a leak on a pitched roof is on our roof repairs page.

Check us first: Bournemouth Roofing & Building Ltd, company number 15471719, owned and run by Thomas Hannen.

Request a free quote Roof repairs on tiled and slate roofs

Finished grey GRP flat roof with three rooflights, formed upstands and the fall running to the outlet

Look at the deck first The boards decide the job. The covering follows them.

The roofs

Garage, extension, dormer, balcony and block roofs

Flat roofs in Bournemouth sit on garages, rear extensions, dormers, bays, porches, balconies and the tops of blocks of flats. Each one fails at the join with something else, and each is priced on the deck as well as the covering, so the type of roof tells you where to look first.

Garages, Outbuildings and Porches

Often the original felt on chipboard, with no upstand worth the name and a gutter screwed to a rotten edge. The deck is the real cost, and a covering over old boards is money spent twice. Porches and canopies are the same job in miniature.

Single Storey Extensions and Rear Additions

A rooflight or two, an abutment along the house wall and a heated room underneath, so the insulation build up matters. A warm roof raises the finished level, which matters at a door or sill. A thin quote prices the covering and skips the layers below.

Dormer Cheeks, Dormer Tops and Bay Roofs

Small areas, heavy detailing. A dormer top wants a welt or trim at the front, a cheek needs the covering dressed in behind the tiles, and a bay roof sheds into a gutter too small for it.

Balconies, Walkways and Flat Sections Between Slopes

Anything you walk on needs a covering that takes a boot, a threshold that keeps water out, and a fall that does not run back at the door. A flat section between two pitched roofs has both slopes draining over it and no room for a fall.

Blocks of Flats and Shared Roofs

Around half the homes in the census areas nearest Bournemouth town centre are flats, so plenty of flat roofs here are shared. A roof over a block is normally the freeholder's or the management company's to repair, and the managing agent instructs it. Where the cost to any one leaseholder passes the limit in the consultation regulations, section 20 of the Landlord and Tenant Act 1985 requires a consultation that takes weeks. A written itemised quote at the start keeps it moving. More on our landlords and agents page.

Shops, Offices and Small Units

Bigger, plainer roofs with plant, parapets and several outlets, where single ply and hot melt earn their keep. See our commercial roofing page.

Repair or replace

Repair, re-cover or replace: the deck decides

A flat roof with one failed detail on a firm, dry deck needs a repair. A tired covering on a sound deck can take a re-cover. A soft, wet or rotten deck means stripping the roof and starting again. The way to tell is to lift a corner and stand on the boards. Looking at the surface from a ladder tells you very little.

Repairs: one detail on a sound deck

A split at a lap, a blister that has lifted, a failed seam, a leaking upstand or a trim worked loose in a gale. On torch-on felt the failed area is cut out, primed and a patch welded in under a fresh cap sheet. A crack along a joint in GRP is ground back and re-laminated. A lifted seam in EPDM is cleaned, primed and bonded again. On a garage roof, each is a few hours of work.

Re-covers: a new covering on the old deck

Once a covering has gone brittle right across, patching stops being worth your money. On a firm, dry deck, a new system goes on the same boards, or a compatible one straight over the old covering, and you save the re-deck. Over soft chipboard or a wet joist end it fails at the same spot inside a winter or two.

Replacement: strip, re-deck and rebuild

Soft or spongy boards, water still sitting a week after rain, several leaks at once, or a roof that has been patched and coated a few times already all point to a full strip. The old covering and deck come off, bad joist ends are cut back, the falls are reset, and the roof goes back as a warm deck with new insulation. Whichever it is, the reasoning comes in writing with the quote.

The systems

Which flat roof covering is best: EPDM, GRP, felt or single ply?

No flat roof covering is best on every roof. EPDM rubber suits a plain rectangle, GRP fibreglass suits roofs with kerbs, openings and foot traffic, torch-on felt suits awkward shapes and changes of level, and single ply suits large plain areas. BS 6229:2025, the code of practice for flat roofs, covers falls, decks, insulation and condensation as well as the covering itself.

EPDM rubber

A single sheet of rubber bonded over the whole deck. On most domestic roofs it goes down in one piece with no joints across the field, which removes the thing that fails on nearly every other system. It is cold laid, flexes as the timber moves, and is too soft for a balcony.

GRP fibreglass

Chopped strand mat and resin laid wet onto a fresh ply deck and cured in place, then topped with a coloured flowcoat. It comes out hard, seamless and walkable, with trims and upstands formed in the same laminate. GRP is rigid, so the deck has to be new, dry and firmly fixed, and resin will not cure cold and wet.

Torch-on felt and built up three layer

Modern reinforced bitumen membrane, torched or hot bonded in two or three layers with the laps staggered, nothing like the thin felt people remember peeling off a garage. Three layers give redundancy and follow an awkward shape. On a timber dormer a cold applied cap sheet replaces the torch.

Single ply

Thin sheet, usually PVC or TPO, laid loose or mechanically fixed and joined by hot air welding in place of adhesive, so the seam can be probed. It belongs on bigger, plainer areas, over a whole ground floor or a block.

Liquid coatings and hot melt

Liquid-applied systems are brushed or rolled on with a reinforcing fleece and cure into a seamless skin, good round a cluster of pipes or an awkward upstand. They need a sound, dry surface. Rolled over a wet deck or blistered felt, a coating seals the water in and the rot carries on underneath.

Hot melt is a rubberised bitumen laid hot onto a concrete deck, usually with insulation and ballast or paving on top, for concrete roofs such as some blocks and podiums. Our guide comparing GRP, EPDM and felt flat roofs covers how the three common systems wear.

Underneath

The deck, the falls and the insulation underneath

The deck, the fall and the insulation decide how long any flat roof lasts, and none of them can be judged from the ground. A covering on firm ply, laid to a proper fall over a warm deck, outlasts the same covering on damp chipboard with a puddle in the middle.

Ply, OSB and chipboard

Flat roof decks are ply, OSB or chipboard. Exterior grade ply is what goes back: it holds a fixing, takes a soaking, and GRP bonds to it. OSB is fine in a dry warm deck. Chipboard belongs on a floor, yet plenty of older garage and extension roofs have it, and damp chipboard swells and loses its screws. Under the boards, joist ends at an abutment or under a leaking outlet rot while the middle stays sound. They are cut back and sistered or replaced before the re-deck.

Firrings, falls and standing water

A flat roof is not flat. It is a very shallow slope, made by firrings, which are tapered timbers over the joists, or by tapered insulation cut to fall, and the fall has to arrive at the outlet. Old roofs lose it as joists deflect. Ponding, water still standing days later, sits on a lap and freezes there. Coating over it does nothing. The answer is firrings, tapered insulation, or a new outlet at the low point.

Warm deck, cold deck and the vapour control layer

A flat roof is insulated as a warm deck or a cold deck, and the two are opposites. A warm deck puts rigid PIR above the deck, with a vapour control layer under it and the waterproofing on top, so the timber stays on the warm dry side, and tapered PIR gives insulation and fall in one layer. A cold deck puts the insulation between the joists with a ventilated void above, and it works only if that void is open at both ends.

Get that wrong and you have interstitial condensation: warm damp air condensing on the cold underside of the deck, rotting it from inside and looking exactly like a leak. A continuous vapour control layer stops it, and Approved Document C covers condensation in roofs. Strip a roof over a heated room down to the deck and it counts as renovating a thermal element, so the insulation has to reach Approved Document L where it is practical to. That is the line a cheap quote leaves out.

Fault finding

Why is my flat roof leaking? Puddles, blisters, splits and stains

A flat roof leak nearly always starts at an upstand, a lap, an outlet or an abutment, and the stain inside is rarely below it. Water gets through at a detail, runs along the deck or down a joist, and drops where something stops it. Each visible fault points to a different cause and a different repair.

Common flat roof faults, what causes each and what puts it right.
What you see	What it usually is	What it damages	What puts it right
A puddle still there a week after rain	The fall has gone, or the outlet is above the low point	Every lap and trim it sits on, then the deck	Reset the firrings or lay tapered insulation to fall
Bubbles and blisters lifting off the surface	Moisture trapped under the covering, expanding in sun	The bond, which fails around each blister first	Cut back to sound material, dry it, re-lay
A straight split, often over a joint below	Movement a brittle covering could not follow	The boards under the split, within one wet winter	Re-deck the moving area, then a system that flexes
A lap or seam curling up at the edge	A cold bonded joint, or water standing on the lap	Everything downhill, once wind gets under	Welded or fully bonded seams, and fix the ponding
Stain in the middle of the ceiling, roof looks fine	Water in at an upstand, tracking along a joist	Plaster and insulation away from the entry point	Trace it from the details inwards, not from the stain
Damp underside with no leak anyone can find	Condensation in a cold deck with a blocked void	Deck boards and joist ends, for years	Open the void, or rebuild it as a warm deck

Some of those are a morning's work and some are the whole roof off, so a quote that prices every fault the same way is guessing. Check the gutter too: a hopper backing up under the edge trim looks like a roof leak from inside. Our guide to a brown stain on the ceiling helps you tell a roof leak from condensation or plumbing.

Detailing

Upstands, trims, rooflights, lanterns and outlets

The open middle of a flat roof almost never fails. Leaks start at a change of direction, a joint or a hole: the upstand, the edge trim, the rooflight kerb, the lead at an abutment and the outlet. Those details are most of the labour on a small roof.

Upstands and kerbs. Where the roof meets a wall the covering turns up and keeps going, high enough that driving rain and leaves cannot get behind it, and fixed mechanically.

Edge trim, drip and apron. At the open edges the covering finishes into a trim that throws water clear into the gutter. Wind suction is strongest at the edges and corners of a roof, so trims, drips and aprons go into sound timber. A trim on a rotten fascia moves, and wind gets in.

Laps and seams. Single ply is hot air welded, felt torched or hot bonded with staggered laps, EPDM joined with seam tape and primer. GRP has no seam at all.

Rooflights, lanterns and skylights

A flat rooflight, a lantern or a skylight is a hole in your roof with a frame in it. Each one sits on a kerb built proud of the roof, the membrane dressed over it and the frame set on finished work, with the fall worked out so water runs round the kerb. Treat an old rooflight as fragile. A new lantern means trimming joists, which is structural work. Soil and vent pipes and a boiler flue each get a purpose made collar and a line on the quote.

Abutments, lead flashings and parapets

Where the roof meets a taller wall, the covering turns up as an upstand and a code rated lead flashing comes down over it, set in a chase raked into a mortar joint or behind a cavity tray. Lead goes in short lengths so it can move without splitting. A parapet takes weather on three faces, and a coping with open joints or no drip lets water into the wall, where it gets blamed on the roof.

Outlets, hoppers and downpipes

A flat roof drains through an outlet, a chute or an open edge into a gutter. Outlets sit at the low point with a leaf guard, and a hopper head on the wall is an easy place for leaves to block. Clearing the whole rainwater run is on our gutter cleaning page, and replacing the boards, boxing and gutters at the edge is on our fascias, soffits and guttering page.

Panels and planting

Solar panels and green roofs on a flat roof

Solar panels can go on a flat roof, but the covering under them has to outlast them. Lifting an array to re-cover a roof later is a job in itself, so if the membrane is near the end of its life, re-cover first and fit the panels after. Mention planned panels at the survey, and the roof and its details are priced with them in mind.

Flat roof panels sit on angled frames. Ballasted frames are held down by weight on protection pads, with no holes through the roof, so the deck and joists have to carry that weight. Fixed mounts go through the covering, and every fixing then needs a flashed collar or kerb like any other penetration. Whoever fits the panels, the waterproofing round them decides whether the roof stays dry.

A green roof, sedum or planted, sits over the waterproofing with a root barrier, a drainage layer and a growing medium. Wet, it is heavy, so the joists and deck need a structural check first, and the outlets still need to be reachable for clearing. EPDM and single ply are the usual layers underneath.

Permission and safety

Re-covering an existing flat roof is repair and maintenance, so it needs no planning application, as Planning Portal guidance on roofs confirms. Planning comes in when you change the shape or height, or turn the roof into a terrace. Building control is a separate question, and stripping a roof over a heated room back to the deck does need notifying.

Conservation areas and listing change the planning side. BCP Council is the planning authority for Bournemouth and lists its conservation areas, East Cliff, The Saints and Westbourne among them. Inside one, changing how a visible flat roof looks, such as a dormer or bay, a new lantern or a roof turned into a terrace, needs checking against the address first. A listed building needs listed building consent for work that affects its character, and a change of covering can be exactly that. The boundaries do not follow the roads you expect, so check the address, not the district.

Building control for Bournemouth is also BCP Council. Take a flat roof over a heated room down to the deck and it counts as renovating a thermal element, so the insulation has to meet Approved Document L where it is practical to, and the work has to be notified: a building notice or a full plans application, or self-certification by an installer registered with a competent person scheme. Ask any quote who is notifying building control, and keep the completion certificate, because a buyer's solicitor may ask for it. Our guide to planning, building regulations and listed building consent sets out each one.

Even a garage roof is work at height, and HSE rules on roofwork are why edge protection or a scaffold is a priced line and never a saving.

What it costs

How much does a flat roof cost? What decides the price

A flat roof is priced on what the deck turns out to be, how many details there are and how you get up to it, not on the area of the covering. A fair price by the square metre does not exist, because a plain garage roof and an extension with two rooflights, an abutment and a parapet are not the same metre. The site visit and the written itemised quote are free.

What the survey is measuring

The deck, the falls and the build up. Ply, OSB or chipboard, how it feels underfoot, whether the joist ends are sound, whether the fall still reaches the outlet, and whether it is a warm deck or a cold deck with a void to reopen.
How many details there are. Upstands, kerbs, trims, outlets, rooflights, lanterns, vent pipes, lead flashings, parapets and copings, counted one by one.
Access and waste. A garage on an open drive is a tower job. A rear extension behind a terrace means a scaffold and a long carry. Then the gutter work, making good inside, and the skip.

The cheapest honest way to fix a flat roof

The cheapest fix is the smallest one that lasts. Repair a single detail on a sound deck first. If the covering is worn out but the deck is firm and dry, re-cover it. Strip it only when the deck has gone. A coating rolled over a wet or failing deck is the false economy: it costs less on the day and the whole roof comes off anyway.

Reading two flat roofing quotes side by side

Ask whether anyone lifted the covering and stood on the deck, or priced it from the garden. Ask what happens if the boards are worse than they look, in writing, before the job starts. Ask which system is going on and why that one for this roof, and whether insulation and the vapour control layer are in it. Ask how many upstands, trims and outlets are in the price, and whether the scaffold and the skip are. Two prices for one roof are usually two different jobs. Our guide to what a roofing quote should include has the full list.

The membrane is the last decision on a flat roof, not the first. The strip out, the deck, the falls, the insulation, each detail, the rainwater work and the making good all get their own line, and anything extra is photographed and priced first.

Before you hire

How to tell a good flat roofer from a dodgy one

A flat roofer worth hiring looks at the deck before pricing, puts the price in writing line by line, and is easy to check on the public record. A dodgy one prices from the pavement, wants cash or a large payment up front, and pushes you to decide on the doorstep.

Look the company up. A limited company has a number, a registered office and named directors, all free to check on Companies House.
Get it in writing, itemised. Citizens Advice says not to rely on a verbal quote, and to get written quotes from at least three traders before you choose.
Pay in stages, by card or bank transfer. The same Citizens Advice guidance says to pay in stages, not to pay everything up front, and to pay by card or bank transfer, not cash.
Expect someone on the roof. A price from the ground is a guess about the deck.
Walk away from doorstep pressure. Our guide on someone knocking to say your roof is dangerous covers what to do.
Ask the awkward questions. Who notifies building control, and how is anything found under the old covering priced before it is done?

To check us: Bournemouth Roofing & Building Ltd, registered in England and Wales, company number 15471719. Thomas Hannen, the owner, is your one person to ring. Our one verified Checkatrade review scored us 10 out of 10, and the written itemised quote is free.

If it is coming through

Water coming through a flat roof today

If water is coming through a flat roof now, catch it in a bucket, move anything valuable, and ring 07435 839745 instead of using the form. Keep clear of light fittings, and turn that circuit off if water is near one. Where a ceiling is bulging, a small hole at its lowest point over a bucket lets the water out in one place.

From a window, look at the outlet: a choked outlet floods a flat roof in one downpour. Do not walk on a wet roof or near an old rooflight. On a block, tell the managing agent in writing too.

Where it is safe to get up, the first visit makes the roof watertight with a temporary cover so the deck stops soaking up water, and the permanent repair is priced once the deck can be seen. Scheduled work Mon to Fri, 8am to 6pm. Something urgent? Ring, and if we miss you we call back. More on our emergency roof repairs page.

Call 07435 839745

How it runs

How a flat roof job runs, and how long it takes

A flat roof job starts with a free visit, where Thomas lifts a corner, stands on the deck and follows the water to the outlet, and a written itemised quote. On a block, or a balcony over somebody else's flat, he asks who manages the building first. A garage or porch is usually a day or two on site, and an extension with a rooflight and new insulation three or four days.

You have one person to ring from the visit to the finished roof. Nothing is left open overnight, the site is swept at the end of each day and the waste leaves with us. If the deck is worse than it looked once the roof is open, it is photographed and priced before anything extra is done, and you decide.

Questions

Flat roofing questions and answers

Flat roof questions come down to cost, lifespan, timing and who is responsible, and each short answer below points back to the deck, the falls and the details.

How much should a flat roof cost?

Only a price for your roof means anything, and nobody can give one without standing on the deck. The drivers are the state of the deck, the falls, the insulation over a heated room, how many upstands, rooflights and outlets there are, and the access. Compare two or three written itemised quotes line by line.

What is the cheapest way to do a flat roof?

Repair the one detail that has failed, if the deck under it is firm and dry. Next is a re-cover over a sound deck. A full strip and re-deck costs most, and is only worth it when the boards have gone. A coating over a wet deck is not the cheap option, because the roof comes off anyway a few years later.

How long does a flat roof last?

As long as its deck, its fall and its edges allow. Exterior ply, a fall that sheds water to the outlet and well made upstands let EPDM, GRP and felt all give long service. Wet chipboard, ponding and an unventilated cold deck shorten any of them.

Are flat roofs more likely to leak than pitched roofs?

A flat roof has less margin, because water sits on it longer and every lap and upstand has to hold it back without help from gravity. Built to a proper fall, with welded or bonded seams and upstands carried high enough, a flat roof stays dry. Leaks come from details done cheaply or a fall that has gone.

Water sits on my flat roof after rain. Is that a fault?

A film that clears in a day or two is normal. A puddle still there a week later means the fall has gone or the outlet is above the low point. The fix is firrings or tapered insulation, not more coating.

Can you lay a flat roof in the winter?

Most of it, yes, but not every system in every week. GRP needs a dry deck and will not cure properly when it is cold, so a wet fortnight in January moves it. EPDM and felt are far less fussy. You will know which you are choosing before the date is set.

Who pays for the flat roof on a block of flats?

Usually the freeholder or the management company, through the service charge, and the managing agent instructs the work. Above a set cost per leaseholder a section 20 consultation comes first. If water is coming into your flat, report it to the agent in writing. A free site visit puts the fault in writing so the agent has something to act on.

Areas covered

Flat roofing across Bournemouth, Poole & Christchurch

Bournemouth Roofing & Building works on flat roofs across Bournemouth from Boscombe, where the business is based at 80a Wolverton Road, BH7 6HX. That takes in Southbourne, Westbourne, Moordown, Kinson and the streets between, and out to Poole, Christchurch, Wimborne and Ferndown. For everything else we do in town, see roofers in Bournemouth.

Builders in Bournemouth House extensions See every area we cover

Flat roofing by location

Flat roofing in every town and village we cover

Each page is written around the flat roofs that are actually there: how much of the housing carries a garage or extension roof, how exposed the edges and trims are, and what the planning position does to a change of covering. A page for every place we cover, grouped by area.

Bournemouth, Poole and Christchurch

Ringwood, Fordingbridge and the Avon valley

Ringwood
Hangersley (also Hightown)
Burley (also Burley Street)
Bransgore
Sopley
Thorney Hill
Fordingbridge
Sandleheath
Rockbourne (also Martin)
Breamore (also Woodgreen)
Hyde (also Frogham, North Gorley and more)
Downton
Redlynch
Lover

The New Forest and the Solent shore

New Milton
Barton on Sea
Bashley
Ashley
Milford on Sea
Everton (also Hordle)
Lymington
Walhampton and Portmore (also Pilley)
Boldre (also Sandy Down, Tiptoe and more)
East Boldre
Brockenhurst
Lyndhurst
Minstead
Cadnam and Bartley

Flat roofing guides

GRP, EPDM or felt: which flat roof covering? Snow on a flat roof or a conservatory Warm roof or cold roof: which do you need?

Flat roofing in Bournemouth: repairs, re-covers and new flat roofs