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Roofer stripping old felt from a flat roof in York before recovering
Cost guide · Flat roofs

What a flat roof replacement costs in York

The covering drives the figure. We lay GRP fibreglass at about £110 to £160 per square metre and lead at £220 to £290. Here is what sets the price, and which one suits your roof.

WORDS ELLIOTT LANGAN, FOUNDER PUBLISHED 16 SEP 2026 READ 7 MIN

01Flat roof replacement cost by material

The first thing to understand about a flat roof is that the covering does most of the pricing. The deck below it and the size of the roof matter, but the material you lay on top is what separates one quote from another. That is why we price a flat roof replacement by the square metre for the covering, then add the deck, insulation and detailing on top. We lay two coverings, GRP fibreglass and lead, and the bands below are for the covering itself, supplied and fitted, from flat roofs we have quoted across York and the villages.

MaterialBest suited toPer square metre
GRP fibreglassgarages, extensions, dormers, balconies£110 to £160
Lead (code 6)porches, bay tops, period dormers, heritage work£220 to £290

Indicative bands plus VAT, correct as of September 2026, for the covering supplied and fitted. Your price is fixed in writing within 24 hours of the free survey, or get a band now with the instant estimate tool.

02What moves the price

Two flat roofs of the same size can be several hundred pounds apart before you even pick a material. Five things do most of the moving:

FACTOR 01Deck conditionOnce the old covering is off we sometimes find soft or rotten decking. Sound boards stay put and keep the price down; a new deck adds material and labour.
FACTOR 02Insulation to warm-roof specA habitable room needs insulation built into the roof to meet building control. That upgrade costs more than a like-for-like recover on a garage.
FACTOR 03Upstands and trimsEvery wall abutment, kerb and edge needs a proper upstand and trim. The more edges and changes of level, the more detailing labour.
FACTOR 04AccessA ground-floor garage roof is quick. A first-floor extension or a dormer needs scaffold or a tower, which adds cost before any material is laid.
FACTOR 05DisposalStripping old felt, bitumen and any wet insulation is dirty work, and the waste is charged by weight. A heavily built-up old roof carries more away.

03How size and shape change the figure

Bands by the metre are useful, but most people want to picture their own roof. On a garage or a simple rear extension the area is regular and the edges are few, so the covering makes up most of the bill. The warm-roof insulation a habitable room needs then lifts the figure again. A dormer is the opposite case: the area is small, but it is nearly all edges, upstands and detailing, so the cost per square metre climbs. Lead porches and bay tops work the same way, where the shaping and dressing take longer than the flat area suggests. For an exact figure on your own roof, the instant estimate tool gives a band in two minutes and the free survey fixes it in writing.

20–30

Years a GRP fibreglass roof should last on a sound, stable deck, when it is properly laminated and topcoated. Manufacturer service lives, general guidance

04GRP or lead: which suits your roof

GRP fibreglass is our choice for most flat roofs. It is laid wet, so it forms one continuous shell around any shape, upstand or odd corner with no joints, and the hard finish takes foot traffic, which makes it the one for a balcony or a roof you will walk on. Lead costs more per square metre and earns it on smaller roofs where looks matter as much as weather: porches, bay tops, dormers on period houses and conservation work, where nothing else sits right against the brick and stone.

GRP fibreglass flat roof in York by EJL Roofing
GRP FIBREGLASS, SEAMLESS AND WALKABLE
Lead-clad dormer on a red clay tiled roof in York
LEAD-CLAD DORMER ON A PERIOD ROOF

05What a proper flat roof job includes

A price worth paying for is more than a new top layer. When we quote a replacement the figure carries the strip-out and disposal, any deck repairs the survey finds, the insulation a habitable room needs to meet building control, the covering you chose, and every upstand, trim and drip edge done properly. It also carries our 20 year workmanship guarantee in writing, on top of the manufacturer's warranty on the materials.

The honest verdict

Beware a flat roof quote that is far cheaper than the rest. The saving is almost always the insulation, the deck repair or the edge detailing, the parts you cannot see and the parts that let water in first.

06Questions we hear every week

How much does it cost to replace a flat roof?
It depends on the covering and the roof. GRP fibreglass runs about £110 to £160 per square metre and code 6 lead £220 to £290, supplied and fitted. Deck repairs, insulation, edge detailing and access sit on top, and your figure is fixed in writing within 24 hours of a free survey.
Should I choose GRP or lead for a flat roof?
GRP fibreglass suits most flat roofs: garages, extensions, dormers and balconies. It forms one seamless shell and takes foot traffic. Lead costs more per square metre and is the choice for smaller roofs where appearance matters, such as porches, bay tops, dormers on period houses and conservation work.
How long does a GRP flat roof last?
20 to 30 years on a sound, stable deck that is properly laminated and topcoated. The deck and the workmanship matter more than the resin itself, which is why we check the deck at survey and back the roof with a 20-year written workmanship guarantee.
Does a new flat roof need to be a warm roof?
Building control expects a habitable room to meet warm-roof insulation standards when the covering is replaced. A detached garage or outbuilding usually does not. We confirm what applies to your roof at the free survey and handle any sign-off as part of the job.
EL
Words by Elliott Langan, Founder · CHECKED 16 SEP 2026

Elliott founded EJL Roofing Residential and has worked on York roofs since 2010. Every job carries a 20 year workmanship guarantee.

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