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Flat Roof Specialists — EPDM, GRP & TPO in Greenwich

Flat Roof Replacement in Greenwich, London

Flat roofs are everywhere across London — Victorian rear extensions, bay window canopies, ex-council maisonette decks — and most fail for the same reason: no falls, no insulation upgrade, and a re-felt over the top instead of a strip-back. We fix the cause, not just the surface, and handle Building Control and Party Wall Act notices as part of the job.

Greenwich overview

Flat Roof Replacement in Greenwich

A large stock of Victorian and Edwardian houses with essentially no dedicated roofing competitor coverage. Greenwich falls well within the South East London ground Lian Construction covers on a regular basis. For EPDM, GRP and TPO flat roof installation, replacement and leak repair in Greenwich, that local knowledge means fewer surprises once work is on site and a team that already understands the borough's typical property stock.

Greenwich has a large stock of Victorian and Edwardian houses, much of it terraced or semi-detached, built in the decades either side of 1900 as London's suburbs expanded along the riverside and rail lines. As with similar housing across inner and near-inner London boroughs, roofs on these properties are typically slate or clay tile, often with parapet walls, valley gutters, and multiple original chimney stacks. Many houses will have had partial re-roofing, loft conversions, or rear extensions at some point over the past century, which means roof coverings and detailing are frequently mixed ages even on a single property. Bay windows with their own small roofs, and shared or party-wall guttering between terraced neighbours, are common features that need particular care during repair work. Given the age of this housing stock, issues such as slipped or missing tiles, ageing lead flashing around chimneys, and worn valley gutters are the kind of thing homeowners in Greenwich are likely to encounter periodically, rather than one-off problems. Property condition varies a good deal street by street depending on maintenance history, so what one house needs can differ significantly from its neighbour.

With a large stock of Victorian and Edwardian houses and essentially no dedicated roofing competitor coverage in the area, homeowners and landlords in Greenwich are often left choosing between general builders who treat roofing as a sideline, or firms based further afield who may not prioritise smaller local jobs. This gap tends to show up most clearly with urgent repairs, where a slipped tile or a leak after a storm needs someone who can attend quickly rather than fit the job in around larger contracts elsewhere. It also affects planning and quoting for larger work such as full re-roofs or chimney repairs, where a lack of specialist local knowledge can mean longer lead times or less accurate initial assessments. For landlords managing older rental stock, this matters because roof issues left unresolved tend to escalate into damp and interior damage, which is more disruptive and costly to fix than catching problems early. Homeowners undertaking wider refurbishment work, such as loft conversions or extensions, may also find it harder to coordinate roofing specifically as part of a bigger project if there isn't a contractor locally who covers that trade in depth. In practice, this means demand for reliable, responsive roofing and refurbishment work in Greenwich likely outstrips the readily available supply.

Given the concentration of Victorian and Edwardian houses in Greenwich, conservation area and, in some cases, listed building considerations are worth checking before starting roofing or exterior refurbishment work. As in many outer and inner London boroughs with older housing stock, parts of Greenwich may fall within conservation areas, where changes visible from the street, such as replacing roof coverings with a different material, altering rooflines, or adding roof windows to a front elevation, can require planning permission even where similar work elsewhere would be permitted development. Chimney stacks and original architectural detailing are often specifically protected in these areas. It's worth checking with the local planning department or a surveyor early on, since retrospective permission is harder to secure than getting it sorted before work starts. This doesn't apply to every property, and plenty of routine repairs and like-for-like replacements fall outside these controls, but it's a sensible thing to verify given the age of the housing stock.

Typical flat roof replacement prices in London
ItemTypical range
EPDM recover (per sqm)£80–£120
GRP fibreglass (per sqm)£90–£140
TPO single-ply (per sqm)£85–£130
Typical 20-30 sqm extension roof (full warm-deck upgrade)£3,000–£5,500

General London market guidance, not a fixed quote — actual pricing depends on a site survey. Full breakdown: cost guide.

Why London's Housing Stock Makes This a Specialist Job

A large share of London's flat roofs sit over single-storey rear extensions, bay windows and dormer cheeks on Victorian and Edwardian terraces, plus the bigger walkway and balcony decks on 1960s-80s ex-council flats and maisonette blocks. Victorian and Edwardian rear extensions were frequently built with almost no fall at all, because the original felt or asphalt covering of the period wasn't expected to last more than a decade or two and falls weren't treated as a design priority the way they are now - which is why so many of these roofs pond in the same spot year after year no matter how many times they've been re-felted. Cold deck flat roof condensation rot repair is the recurring job on ex-council and maisonette roofs from the 1960s-80s: these are usually cold-deck construction, with the insulation sitting below the deck rather than above it, so a void forms above the ceiling where condensation collects and rots the joists and deck boarding from underneath - invisible until the covering comes off. These blocks also often have felt dressed over timber upstands that have since rotted, letting water track down inside a shared parapet wall and show up as a damp patch in a flat one or two doors along, which makes the leak hard to trace back to its source without opening the roof up. Access and consent differ between the two building types as well: a house recover is usually a private decision, while an ex-council flat roof normally needs freeholder or management company consent alongside a different planning route, since permitted development for like-for-like recovering doesn't apply to flats at all. Both building types need the roof treated as one system - deck, falls, insulation, membrane and detailing - rather than a surface to be resurfaced, and experience with this specific housing stock counts for more than general roofing competence.

EPDM vs GRP vs TPO vs Felt: Choosing the Right Membrane

EPDM is a single-sheet rubber membrane with very few joints, stays flexible through London's freeze-thaw winters, and is generally rated at 25 years or more, which makes it our default recommendation for most domestic extension and dormer roofs - fewer joints means fewer places for water to find a way in over the roof's life, and it tolerates minor deck movement well. GRP fibreglass laminate cures into a seamless, hard-wearing, walkable surface and looks excellent on completion, which suits roofs used for informal access, but it needs good ventilation and stable ambient conditions during lay-up because of the resin involved, and being a rigid laminate it doesn't flex with a building that moves slightly - which is why older GRP roofs sometimes crack at corners, movement joints and parapet junctions even when the main field is sound. TPO is a newer single-ply system with hot-air welded seams that we generally specify on larger warm-deck roofs, where bigger sheet sizes and mechanically strong welds suit the scale better than domestic EPDM or GRP runs, rather than fiddly detail work around dormers and bay windows; manufacturers typically back it with guarantees in a similar bracket to EPDM, though it has a shorter track record in UK domestic roofing than either EPDM or felt, so we tend to reserve it for larger commercial-style flat roofs rather than small extension jobs. Felt is the cheapest option at £45-£75 per sqm but only lasts 10-15 years and is more prone to splitting, blistering and ponding damage well before that if falls weren't corrected at installation, so we'll quote it if budget is the deciding factor but won't recommend it as a long-term fix.

Falls checked and corrected with tapered insulation or firrings before covering goes down, rather than laid over the original near-flat Victorian deck and left to pond again
Deck always stripped back to sound timber and inspected, never overlaid on old failed felt, which traps moisture and typically invalidates the manufacturer's guarantee
Every recover specified as a genuine warm-deck build-up to the Part L U-value target of 0.18 W/m2K, not a like-for-like re-felt that ignores the thermal element rules
Regular coverage of Greenwich and the wider South East London area

Signs to look for

Do you need flat roof replacement in Greenwich?

  • Standing water is still visible on the roof surface a day or more after rain has stopped, especially on a Victorian or Edwardian rear extension roof - a sign the deck was never given proper falls and the membrane is now sitting in a permanent puddle that's degrading far faster than its rated lifespan.
  • A damp patch or brown ring has appeared on a ceiling directly under a flat roof, especially one that only shows up after heavy or prolonged rain rather than every time it rains - classic sign of a failed detail rather than a fully perished membrane.
  • The flat roof has been re-felted or re-covered more than once without ever being stripped back to the timber deck - each layer traps the last one's faults and moisture, so you're paying to hide the same problem rather than fix it.
  • Felt is bubbling, cracking, or curling at the edges, or GRP laminate has spider-cracked at a corner, upstand or where it meets a brick parapet - the field of the roof can still be sound while the junction detail has already failed.

How the work is handled in Greenwich

  1. Step 1Survey the existing roof build-up on site - identify whether it's warm-deck or cold-deck construction, take moisture readings in the deck, and lift a sample area if rot is suspected before anything is priced.
  2. Step 2Agree the regulatory route with you - full plans submission for anything structural like a raised parapet, roof terrace or new insulation build-up, or a building notice for a straightforward recover - and confirm whether planning permission applies given your property type and conservation area status.
  3. Step 3Serve Party Wall Act notice on the adjoining owner where the work involves a shared parapet, upstand or structural element, and allow the statutory notice period before work starts.
  4. Step 4Erect scaffold or edge protection, arrange a skip, and sheet the roof opening so the building stays weathertight while the covering is off.
  5. Step 5Strip the existing covering back to the structural deck and inspect joists, boarding and any timber upstands for rot, replacing anything unsound before insulation goes down.
  6. Step 6Install the insulation as a genuine warm-deck build-up - PIR boards sized to hit the Part L 0.18 U-value target - with a continuous vapour control layer beneath it.
  7. Step 7Form correct falls using tapered insulation or firrings rather than following the old deck shape, then lay new deck boarding where the original has failed.
  8. Step 8Install the chosen membrane - EPDM adhered or mechanically fixed, GRP laminated with resin and topcoat, or TPO with hot-air welded seams - with falls running correctly to the outlets.
  9. Step 9Detail every upstand, parapet junction, trim, drip edge, outlet and rooflight to the membrane manufacturer's specification, since this is where flat roofs actually fail even when the main field is sound.
  10. Step 10Book and pass the Building Control inspection, obtain the completion certificate for the thermal element renewal, clear the site, and hand over the manufacturer's guarantee documentation.

Questions

Flat Roof Replacement questions in Greenwich

How quickly can Lian start EPDM, GRP and TPO flat roof installation, replacement and leak repair in Greenwich?

Greenwich is part of our regular South East London coverage, so once we've surveyed the property we can usually confirm a start date quickly. Send the address and scope and we'll arrange the next step.

Do you cover all of Greenwich?

Yes. Greenwich falls within the area Lian Construction serves across Greater London.

Do I need planning permission to replace my roof in Greenwich?

It depends on the property and whether it sits in a conservation area, and on what you're changing. Straightforward like-for-like re-roofing is often permitted development, but altering the roofline, changing materials, or adding rooflights on a front-facing slope can require permission in conservation areas, which cover parts of Greenwich. We'd always recommend checking with the council or a surveyor before committing to work, since it's much easier to sort out beforehand than after the fact.

How much does GRP fibreglass roofing cost per square metre?

GRP (fibreglass) typically runs £90-£140 per square metre installed, sitting above EPDM's £80-£120 and TPO's £85-£130 because the resin, matting and topcoat are labour-intensive to lay up correctly and need stable temperature and humidity on the day - rushing GRP in poor conditions is one of the more common causes of early failure. The finished laminate is seamless, walkable and looks excellent on handover, which is why it suits roofs used for informal access such as a bay window canopy people step out onto, but the labour cost reflects genuine skill in getting the resin cure right, not just material price. On a typical 15-20 sqm dormer or extension roof, that puts a straightforward GRP recover at roughly £1,500-£2,800 before any rot repair or insulation upgrade is added, with the same access and job-minimum rules applying to small roofs as with any other membrane.

How many years does an EPDM roof guarantee actually last?

Manufacturer guarantees on EPDM in the UK are typically in the 20-25 year range, and the membrane itself is generally reckoned to perform for 25 years or more in practice, which is longer than most other single-ply options fitted on London's older housing stock. The guarantee is usually conditional on two things: the installer being trained or approved by that specific manufacturer, and the detailing at upstands, trims and outlets following their specification exactly, rather than a generic install. It's also a guarantee on the membrane itself, not automatically on the whole roof build-up - if the deck was rotten underneath or the falls were never corrected, the membrane can still be within its guarantee period while the roof leaks for an unrelated reason. Ask any contractor quoting EPDM to show you what the guarantee document actually covers, not just quote you a number verbally.

Do I need planning permission or Building Control sign-off to replace a flat roof?

For a house, like-for-like re-covering of an existing flat roof is usually permitted development and doesn't need planning permission, though that exemption doesn't apply to flats or maisonettes at all, doesn't cover a roof terrace or balcony, and can be removed in a conservation area with an Article 4 direction - common across parts of Kingston, Richmond and inner London. Building Control is a separate requirement and applies in almost every case: because a recover or replacement counts as renewal of a thermal element under Approved Document L, the new build-up has to hit a 0.18 W/m2K U-value, which means a full plans submission for anything structural like a raised parapet or terrace, or a building notice for a straightforward recover. Either route ends with a completion certificate, which you'll want on file if you ever sell, remortgage, or need to satisfy an insurer that the work was compliant.

Talk to Lian Construction about Greenwich

Send the site address in Greenwich, photos if available, and the flat roof replacement work you need. We can review the scope and arrange the next step.

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