Summary

Garage roofs look like a simple job — small area, low value, often single storey — but they hide more pricing traps than almost any other roofing work. The covering on a garage built before 2000 is very often corrugated cement sheet, and cement sheet of that age frequently contains asbestos. You cannot legally smash it up, jet it, drill it or skip it as general waste. It has to be identified, and if it's asbestos-containing it must be removed by appropriate methods under the Control of Asbestos Regulations 2012 (CAR 2012), double-wrapped, and disposed of as hazardous waste through a licensed route. This single factor can be the difference between a £900 job and a £2,200 job, so it must be assessed and priced before you commit.

Beyond asbestos, the price drivers are the covering type (felt is cheapest, EPDM mid, GRP and tiles dearer), the condition of the deck and structure beneath (rotten joists or a sagging deck are common and frequently unseen until strip-out), the access (attached garages, integral garages, and shared boundary walls all complicate it), and the waste (the old covering plus any rotten deck has to be carried away by a registered waste carrier). A garage roof is also where Building Regulations can bite if more than 25% of the roof area is renewed — the insulation upgrade trigger applies even to a humble garage.

This guide is for the tradesperson pricing the job: typical labour days, current UK material costs, the asbestos red flag, what to itemise, and a worked example. For the warm-roof flat-roof build-up and detailed EPDM/felt/GRP pricing per m² see flat roof replacement pricing guide and fibreglass roof pricing guide; for the asbestos removal cost in detail see asbestos removal pricing guide.

Key Facts

Quick Reference Table

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Garage type Covering Asbestos? Typical Price (Regional) Typical Price (London)
Single, flat, sound deck Felt (3-layer) No £900-£1,500 £1,200-£1,900
Single, flat, sound deck EPDM No £1,100-£1,800 £1,400-£2,300
Single, flat, new deck needed EPDM No £1,400-£2,200 £1,800-£2,800
Single, flat GRP fibreglass No £1,400-£2,400 £1,800-£3,000
Single, corrugated cement Strip + new sheet/EPDM Yes (likely pre-2000) £1,400-£3,000 £1,900-£3,800
Single, pitched Re-tile (concrete) No £1,800-£3,200 £2,400-£4,200
Double, flat, sound deck EPDM No £1,800-£3,200 £2,400-£4,200
Double, corrugated cement Strip + new covering Yes (likely) £2,800-£5,500 £3,600-£7,000
Integral / first-floor garage EPDM warm roof No £1,800-£3,500 £2,400-£4,500

Detailed Guidance

Step One — Assume Asbestos Until Proven Otherwise

This is the rule that protects your business and your lungs. If the existing covering is corrugated cement sheet (the wavy grey "asbestos cement" sheeting) on a garage built before 2000, treat it as asbestos-containing until a sample says otherwise.

        OLD GARAGE ROOF — ASBESTOS DECISION
                     |
     Is it corrugated/profiled cement sheet?
                     |
        +------------+------------+
        | YES                     | NO (felt/EPDM/tiles)
        v                         v
   Built before 2000?       Standard pricing,
        |                   no asbestos premium
   +----+----+
   | YES     | NO
   v         v
 TREAT AS   Likely
 ASBESTOS   non-asbestos
   |        cement (post-2000)
   v
 Sample/survey BEFORE quoting a strip price.
 Price removal under CAR 2012:
 - Don't break it, don't jet it, don't drill it
 - Double-wrap, hazardous waste consignment
 - Non-licensed work £80-£250/m²

What you must not do: snap the sheets to fit them in a skip, sweep up the broken bits, jet-wash the surface, or send it to a general tip. Breaking asbestos cement releases fibres. The correct route is to keep the sheets whole, wet them down, remove the fixings, double-wrap the sheets in heavy polythene, label them, and dispose through a licensed hazardous waste route with a consignment note. Most garage asbestos cement strip is non-licensed work (it's lower-risk bonded cement, not friable lagging), but it still must be done by competent people following CAR 2012, and the cost must be in the quote. See asbestos removal pricing guide and asbestos.

If you quote a garage strip without an asbestos check and then discover cement sheet mid-job, you face a stop, a survey, a hazardous-waste route, and a difficult conversation about a price rise. Check first.

Step Two — Inspect the Deck and Structure

Once you know what's coming off, find out what's underneath. Old garage roofs hide:

Caveat the deck on the quote: "Price assumes existing deck is sound; deck or joist replacement quoted separately on strip-out at £X/m²." This protects you from the most common garage-roof dispute.

Step Three — Choose and Price the Covering

Covering Life Cost band (fitted) When to recommend
Shed-grade mineral felt 5-10 yrs Lowest Budget only; avoid for a job you guarantee
3-layer torch-on felt 15-20 yrs £40-£70/m² Solid mid-market choice
EPDM rubber 25-40 yrs £55-£90/m² One-piece, few joints, low-maintenance; popular default
GRP fibreglass 25-40 yrs £70-£110/m² Durable, walk-on, but weather-sensitive layup (dry, >5°C)
Concrete tiles (pitched) 40+ yrs per-m² tile + labour Pitched garages matching the house

For most single garages, EPDM is the sweet spot: a one-piece membrane with very few joints, a long life, and a clean strip-and-re-cover process. GRP is excellent but the layup is weather-dependent — don't quote it for a wet week. See flat roof replacement pricing guide for the warm-roof build-up and fibreglass roof pricing guide for the GRP detail.

Step Four — Itemise the Quote

A garage roof quote that protects you separates:

  1. Asbestos check / removal — survey/sample cost, and if found, the CAR 2012 strip and hazardous waste consignment
  2. Strip-out and waste — removing the old covering and tipping, registered carrier
  3. Deck / structure — new deck and any joist repair (caveated as "if required on strip-out")
  4. New covering — type, area, fitted
  5. Trims, fascia, gutter — drip edge, fascia, new gutter and downpipe
  6. Access — tower or scaffold if needed (integral/first-floor garages)
  7. Margin / overhead

Worked Example — Single Garage, Corrugated Cement Roof, Replace with EPDM, Regional

The classic garage job: a 4m × 4.5m (18m²) detached single garage with a pre-2000 corrugated asbestos cement roof, replaced with a new timber deck and EPDM.

Line item Detail Cost
Asbestos sample/confirmation 1 sample £90
Non-licensed asbestos cement strip 18m² @ ~£90/m² £1,620
Hazardous waste consignment double-wrap + licensed tip £180
New deck 18mm OSB3, 18m² supplied + fit £620
EPDM covering 18m² @ ~£70/m² fitted £1,260
Drip trim, fascia, new gutter ~14m £210
General waste (old deck/timber) skip-share £80
Subtotal (cost) £4,060
Margin / overhead @ 18% £731
Quote total (ex VAT) ~£4,791

The same garage with a non-asbestos felt covering and a sound deck would price closer to £1,000-£1,600. The entire difference is the asbestos strip, the hazardous waste route, and the new deck. That is why "assume asbestos until proven otherwise" is the most important pricing rule on garage roofs — and why you check before you quote, not after.

Building Regulations and Notification

For a detached, unheated garage the Building Regulations insulation requirements are usually relaxed, but renewing more than 25% of any roof can engage Part L's "consequential" requirements in principle. For an integral or attached heated garage, or one being converted to habitable space, the insulation, condensation (Part C) and ventilation requirements do apply and the build-up must be a proper warm roof. If in doubt, a quick call to Building Control before you quote saves an expensive retrofit. A garage conversion is a different job entirely — see the wider conversion guides.

Frequently Asked Questions

How do I know if a garage roof is asbestos?

You can't tell for certain by eye — you confirm it by sampling. But the strong indicator is corrugated/profiled grey cement sheet on a building constructed before 2000. Asbestos cement was used extensively for garage and outbuilding roofs until it was banned (the final UK ban on chrysotile was 1999). If it's that material and that age, treat it as asbestos-containing and take a sample (£50-£150) before quoting a strip. After 2000, profiled cement sheet is fibre-cement without asbestos.

Can I just skip the old cement sheets?

No. If they contain asbestos, breaking them to fit a skip releases fibres and sending them to a general tip is illegal. Asbestos cement must be kept whole, wetted, double-wrapped, labelled, and disposed of as hazardous waste through a licensed route with a consignment note. This is a separate, higher tipping cost that must be in your quote.

Is asbestos cement garage roof removal licensed work?

Bonded asbestos cement sheet is generally non-licensed work because the fibres are firmly bound in cement and the risk is lower than friable insulation — but "non-licensed" does not mean "no rules". CAR 2012 still requires competent operatives, correct method (no breaking/jetting), RPE/PPE, and the hazardous waste route. Some situations (poor condition, large quantity) push it toward licensed work. See asbestos removal pricing guide.

Why is the deck so often rotten?

Garage roofs are frequently the cheapest covering on the building, get the least maintenance, and pond water because the original fall was inadequate. Years of a leaking felt roof saturate the OSB or chipboard deck, which delaminates and softens. Always caveat the deck in your quote ("if required on strip-out") because you genuinely won't know its condition until the covering is off.

Felt, EPDM or GRP for a garage?

For most single garages, EPDM is the practical default — a one-piece sheet with minimal joints, a 25-40 year life, and a clean install. Felt is cheaper but shorter-lived. GRP is very durable and walk-on but the layup needs dry weather above ~5°C, so it's a poor choice in winter. Match the customer's budget and the weather to the method.

Regulations & Standards