Commercial roofing costs: how to read the price on each quote
Commercial roofing costs are set by the scope a roofer prices, not by a rate card. There is no free, dated, published source of commercial roofing rates that we can cite, so this page does not print a price list. It shows you how to turn every quote you hold into a price per square metre, what moves that number, which lines make a cheap quote cheap, and how VAT and tax change what the roof really costs your organisation.
Why this page has no rate card
Most of the cost figures online for roofing are written for homeowners, carry no date, or come from a firm that wants the job. A commercial roof is priced from what is under the covering: the deck, the insulation that may or may not be wet, the falls, the gutters, the access over a building that stays open. Two firms looking at the same warehouse can price different systems and different build-ups, and both can be honest. A range copied from elsewhere would give you a number to anchor on and nothing to check it against. The useful numbers are the ones already on your desk: the totals on your quotes and the area each one covers.
So the method here is simple. Put every quote on the same basis, read the price per square metre side by side, and then explain each gap with a line of scope. When the scopes match, the price difference is real. When they do not, the cheapest quote is usually the one that leaves something out.
Step 1: turn every quote into a price per square metre
Divide each quote's total, excluding VAT, by the roof area that quote covers. That sounds obvious, but quotes rarely use the same area. Check four things before you divide:
- Plan area or slope area. A pitched or curved roof has more covering than its footprint. One quote may measure on plan and another along the slope, which changes the rate without changing the work.
- What is priced per linear metre. Gutters, valley linings, verges, ridges and parapet cappings are often priced by the metre. Take them out of the area rate and compare them as a separate line.
- Provisional sums. A provisional sum for deck repairs, asbestos removal or rooflight replacement is a placeholder, not a price. Two quotes with different provisional sums are not yet comparable.
- Preliminaries. Scaffold, edge protection, welfare, skips and site set-up can be shown as one line or spread through the rates. Add them back in so each quote is a whole-job figure.
The sense-check below does the division for you as you type, adds VAT at 20% and shows the gap between your highest and lowest quote. It works only from the figures you enter.
Step 2: explain every gap with a line of scope
Once the quotes are on one basis, the table below is the list of reasons one price differs from another. Work down it with each quote open. Every row is a question you can put to a roofer in writing.
| Cost driver | What to look for on the quote | Why it moves the price |
|---|---|---|
| Deck and existing build-up | Has the roofer taken core samples or opened the roof? Does the quote say strip to deck, overlay or over-sheet? | Wet insulation or a failing deck has to come off. An overlay on a sound, dry roof avoids that cost; an overlay on a wet one traps the problem. |
| Insulation upgrade | A stated build-up and a target U-value, or the words "like for like". | Renewing most of a roof is normally a renovated thermal element under Part L, so the insulation upgrade is part of the job, not an extra. |
| Falls and drainage | Tapered insulation, new outlets or a falls design, or nothing about falls at all. | A flat roof that ponds needs the fall built back in. A quote that is silent on falls has not priced it. |
| Access and edge protection | Scaffold, edge protection, fragile-roof covers, safety netting, a lifting plan. | Working at height over rooflights or fibre-cement sheets needs collective protection under the Work at Height Regulations 2005. It is a real cost, and leaving it out is a warning sign. |
| Occupation and phasing | Bay-by-bay phasing, weekend or out-of-hours working, temporary waterproofing. | Keeping a warehouse, school or production line running below the works lengthens the programme. |
| Wind exposure and fixings | A wind-uplift calculation to BS EN 1991-1-4 and a fixing pattern with perimeter and corner zones. | Exposed and taller roofs need more fixings or more ballast, especially at edges and corners. |
| Asbestos | A refurbishment survey, or an exclusion for asbestos-containing materials. | Fibre-cement sheets and some felts on older buildings contain asbestos. Removal or encapsulation is specialist work with its own price. |
| Gutters, rooflights and details | Gutter lining or renewal, rooflight replacement, upstands, outlets, flashings to plant. | On large metal roofs the gutters and cut edges are often the source of the leak. A quote for the sheets alone may not fix it. |
| Guarantee | Who issues it, for how many years, and whether it is insurance-backed. | A manufacturer or insurance-backed guarantee requires an approved installer and an inspected system, which costs more than a workmanship promise. |
Step 3: find the lines that make a cheap quote cheap
When one quote is far below the others, read its exclusions before its price. These are the lines that most often sit outside a low number:
- Scaffold or edge protection "by others", or access priced only for part of the roof.
- No insulation upgrade on a job that renews most of the roof.
- No falls correction on a roof that ponds.
- Asbestos, deck repairs or rooflights left as provisional sums with low or no figures.
- Gutters, outlets and cut edges not included on a profiled-metal roof.
- A workmanship-only guarantee where the others offer a manufacturer or insurance-backed one.
- Waste disposal, making good inside the building or out-of-hours working excluded.
None of these makes a quote dishonest. They make it a different job. Ask the low bidder to price the missing lines, or ask the high bidders what they would take out to match. Either way, you end up comparing one scope at three prices.
VAT and tax on a commercial re-roof
Work on a commercial building is normally charged at the standard rate of VAT, which is 20%. The reliefs in HMRC's VAT Notice 708 are aimed at new dwellings, certain residential and charitable buildings and some conversions, not at re-roofing a warehouse or an office. A VAT-registered business can normally reclaim the VAT it pays on business costs, so for many buyers the figure that matters is the total excluding VAT. A charity, school or other organisation that cannot fully recover VAT should budget on the VAT-inclusive figure, which the sense-check shows alongside each quote.
For tax, the question is whether the work is a repair or a capital improvement. HMRC's Business Income Manual (BIM46900 onwards) sets out how repairs and renewals are treated. Separately, adding thermal insulation to an existing building used in a business can qualify for capital allowances as plant under section 28 of the Capital Allowances Act 2001. How a particular job splits between the two is a question for your accountant, and it is worth asking each roofer to show the insulation as its own line so the split is easy to make.
Headline price against whole-life cost
A board will often ask for the cheapest number. The fairer comparison is what each option costs over the period you will own or occupy the building. A coating or a patch repair defers spend and may be exactly right on a sound roof with a short horizon. On a roof with wet insulation or failed gutters, repeated repairs keep the cost coming without fixing the cause. When you compare quotes, write down three things for each: the price, the service life the roofer expects, and the guarantee term and backer. A quote that cannot give you the last two is not giving you a whole-life figure. Our repair, refurbish or replace guide walks through that decision.
Questions to send every roofer before you compare prices
- What roof area does this price cover, and is it measured on plan or along the slope?
- Have you checked the existing insulation for moisture, and how?
- What build-up and U-value does this quote design to?
- What falls will the finished roof have, and how is that achieved?
- What access, edge protection and fragile-roof measures are included?
- Is an asbestos refurbishment survey included, and what happens if asbestos is found?
- Who issues the guarantee, for how long, and is it insurance-backed?
- What is excluded, and what are the provisional sums for?
Put the same questions to every firm and ask for written answers. It is the cheapest way to make three quotes comparable, and it is the method the rest of this site is built on. Our quote myths page covers the claims that most often mislead buyers.
Cost questions buyers ask
What does a commercial roof cost per square metre?
There is no free, dated, published source of commercial roofing rates we can cite, so we do not give one. The rate on a real quote is set by the deck, the insulation upgrade, the falls, access over the building and the guarantee. Divide each quote's total by the area it covers to compare them, then check the scope lines on this page.
Why is one of my quotes so much cheaper than the others?
Usually because it prices a smaller scope: an overlay instead of a strip, no insulation upgrade, no falls correction, access or asbestos left out, or a workmanship-only guarantee. Read its exclusions and provisional sums first, then ask the firm to price the missing lines.
Is VAT charged on commercial roofing?
Work on a commercial building is normally charged at the 20% standard rate. A VAT-registered business can normally reclaim it. Organisations that cannot fully recover VAT, such as many charities and schools, should budget on the VAT-inclusive total.
Can I claim tax relief on a new roof?
It depends on whether the work is a repair or a capital improvement, which HMRC's Business Income Manual covers from BIM46900. Adding thermal insulation to an existing business building can qualify for capital allowances under section 28 of the Capital Allowances Act 2001. Ask your accountant, and ask the roofer to show insulation as its own line.
Sources: Approved Document L (gov.uk), HSE guidance on roof work and asbestos, HMRC VAT Notice 708, HMRC Business Income Manual BIM46900, Capital Allowances Act 2001 s28 (legislation.gov.uk). Last checked 25 October 2026. Commercial Roofing Quotes is an independent publisher run by SEO Dons Ltd and does not price or install roofs.