About Our Flat Roofing Service
A well-installed flat roof is durable, weatherproof and low maintenance. Whether you need flat roofing on an extension, garage, dormer, bay window or outbuilding, or an existing flat roof that's reached the end of its life, our team provide reliable and lasting solutions across Sunderland and the North East.
EPDM Rubber
EPDM rubber roofing is one of the most durable flat roofing materials available, with a typical lifespan of 50+ years. It's seamless, UV-resistant and highly resistant to punctures — ideal for extensions and garages.
GRP Fibreglass
GRP (glass reinforced plastic) fibreglass roofing provides a completely seamless, waterproof finish that is extremely strong and long-lasting. It's an excellent choice for flat roofs with complex shapes or penetrations.
Felt Roofing
Modern torch-on felt systems offer improved performance over traditional mineral felt. We use quality three-layer systems that provide reliable waterproofing at a competitive price point.
Full or Partial
Whether a complete new flat roof or a targeted repair to stop a leak, we assess every job and provide honest advice on the most cost-effective solution. We never recommend a full replacement when a repair will do.
Warm Roof or Cold Roof?
This is the single most important decision on a flat roof and the one homeowners are least often told about. It's not about the covering on top — it's about where the insulation sits, and getting it wrong is what causes most of the flat roof problems we're called out to.
Cold roof — the older method
Insulation is fitted between the joists, underneath the timber deck. That leaves the deck itself sitting out in the cold, above the insulation. Warm, moist air from inside the house rises, reaches that cold deck and condenses on it. To stop that, a cold roof has to keep a ventilated air gap above the insulation with clear airflow at the eaves — and the moment that gap gets blocked, squashed by insulation pushed too high, or simply built without enough ventilation, you get condensation. Homeowners then report a "leak" that appears in dry weather, which is the giveaway.
Warm roof — what we fit
Insulation goes above the deck, with the waterproof covering over the top. The whole structure below stays close to room temperature, so there's no cold surface for moisture to condense on and no ventilation gap to maintain or block. It performs better thermally, it's far more forgiving, and it's what we build on essentially every new flat roof now. The trade-off is that it raises the roof height slightly, which occasionally matters at an abutment or under a window.
Upgrading an existing cold roof
If you're replacing an old flat roof covering anyway, that's the moment to convert it to a warm roof. The cost difference is mostly insulation board, because the labour of stripping and recovering is happening regardless. It also matters for compliance: if you're replacing a significant proportion of the covering, building control will normally expect the finished roof to meet current insulation standards, and an old cold roof recovered like-for-like usually won't. We'll tell you where you stand before quoting.
EPDM, GRP or Felt?
All three are good systems when they're fitted properly. Which one suits you depends on the roof, the access and the budget.
| System | Typical life | Best for | Watch out for |
|---|---|---|---|
| EPDM rubber | 30–50 years | Extensions, garages, dormers — a single seamless sheet with no joints to fail, and it stays flexible in North East winters | A visible seam is needed on very large roofs; finish is matt rather than glossy |
| GRP fibreglass | 25–30 years | Balconies, walk-on areas and roofs with complex shapes or lots of penetrations — cures to a hard, walkable surface | Needs dry, mild conditions to lay properly; more brittle than EPDM if the deck moves |
| Torch-on felt | 15–20 years | Outbuildings, sheds and budget-conscious jobs — a modern three-layer system is far better than the single-layer felt it's remembered for | Shortest lifespan of the three; more joints, so detailing quality matters most |
For most domestic flat roofing across Sunderland and the North East we'd recommend EPDM. It handles our temperature swings well, there are no seams to open up on a typical extension or garage roof, and it comfortably outlasts felt. Where a roof needs to be walked on regularly, or where the shape is awkward enough that a sheet won't sit cleanly, GRP is the better answer. We'll tell you which we'd use on your roof and why, rather than fitting whatever we happen to have on the van.
Flat Roof Repair or Replacement?
We get called to a lot of flat roof leaks, and a fair proportion don't need a new roof at all.
When a repair is enough
A single split in the covering, a failed joint, a lifted upstand at a wall abutment or a blocked outlet can nearly always be repaired. If the deck underneath is still firm and the rest of the covering has life in it, patching is the sensible and honest option. Worth knowing: most flat roof leaks happen at the edges — upstands, trims, outlets and where the roof meets a wall — rather than in the middle of the covering. That's usually a detailing failure, not a whole-roof failure.
When replacement is the better value
Replacement makes sense once the deck feels soft or springs underfoot, when water has been getting in long enough to rot the timber below, when there are multiple separate failures across the covering, or when you've got standing water sitting on the roof days after rain because the falls were never right. Ponding water is the thing most likely to shorten a flat roof's life, and it can't be fixed by patching — the falls have to be rebuilt.
If you've got an active leak right now, our emergency leak guide covers what to do in the meantime, and our comparison of GRP versus EPDM goes deeper on the two main systems.
What it costs
Flat roofing is priced by area, so the size of the roof matters most, followed by the system you choose (felt is cheapest, EPDM mid-range, GRP typically highest), whether the deck needs replacing once we strip the old covering, and whether you're upgrading to a warm roof. Access matters too — a garage roof reachable from a ladder costs less to do than a second-storey dormer needing scaffold. Every quote we give is fixed and in writing after a free survey, so you're not working from a per-metre guess.
What's Included
- Free survey and written quotation
- Removal of old flat roof covering
- Inspection and repair of roof deck if needed
- New EPDM, GRP or felt system installation
- Correct drainage falls and outlets
- Lead or aluminium upstands and trims
- Flashings to all abutments and upstands
- Solar reflective coatings where applicable
- 10–20 year manufacturer guarantee (EPDM/GRP)
- Full site clearance on completion
Flat Roofing FAQs
What is the difference between a warm roof and a cold roof?
On a warm roof the insulation sits above the timber deck, so the whole structure stays close to room temperature and there's nothing cold enough inside for moisture to condense on. On a cold roof the insulation sits between the joists below the deck, which leaves the deck cold and means a ventilated air gap has to be maintained above the insulation. Warm roof construction is what we fit on almost every new flat roof now, because cold roofs are far more prone to condensation problems if that ventilation path is ever blocked.
Which is best: EPDM, GRP or felt?
EPDM rubber is a single seamless sheet, stays flexible in cold weather and typically lasts 30 to 50 years, which makes it our usual recommendation for extensions and garages. GRP fibreglass is laid wet and cures to a hard, walkable surface, so it suits balconies and roofs with complex shapes, but it needs dry weather to install properly. Torch-on felt is the most economical and still performs well in a modern three-layer system, though it has the shortest life at roughly 15 to 20 years.
Can a flat roof be repaired rather than replaced?
Often yes. A single split, a failed joint or a lifted upstand can usually be patched, and if the deck underneath is sound that's the sensible option. Replacement becomes the better choice when the covering has multiple failures, when the deck is soft or spongy underfoot, or when water has been getting in long enough to rot the timber below. We survey first and tell you which it is rather than defaulting to the bigger job.
How long does a flat roof last?
It depends entirely on the system. Torch-on felt typically gives 15 to 20 years, GRP fibreglass around 25 to 30, and EPDM rubber commonly 30 to 50. Drainage matters as much as the material — a flat roof with proper falls that sheds water will outlast the same covering laid flat where water ponds.
Do flat roofs always leak?
No — that reputation comes from decades of old single-layer felt laid without adequate falls. A modern EPDM or GRP flat roof with correct drainage falls, properly formed upstands and good detailing at abutments is entirely reliable. Most flat roof leaks we attend are at the edges and junctions rather than in the middle of the covering, which is why the detailing matters more than the material.
Do I need building regulations approval for a new flat roof?
If you're replacing a significant proportion of the roof covering, building control will normally expect the new roof to meet current insulation standards, which a like-for-like recover on an old cold roof often won't. On an extension it's covered by the approval for the extension itself. We'll tell you before quoting whether your job is likely to need it.
Flat Roofing Across the North East
We carry out flat roofing work across Sunderland, Tyne and Wear and County Durham.