What Is the Cost Per Square Metre for Commercial Rooflights?
Commercial rooflights budget at roughly £110 to £190 per square metre for single-skin in-plane GRP, £165 to £270 for twin-skin with a liner, and £520 to £950 for a barrel vault on a new kerb, supplied and fitted on an accessible roof in normal hours. A per-square-metre rate is a budgeting tool, useful for estimating a whole roof, but it misleads when access, phasing or a difficult profile dominate the real cost.
This answer sits under our commercial skylight installation service. It explains what a rate does and does not carry, and when to stop trusting it. Our commercial rooflight replacement cost page covers the full budgeting structure.
The rates by material and build-up
| Build-up | Rate per m² | What sets it |
|---|---|---|
| In-plane GRP, single skin | £110 to £190 | Standard profile, polyester film |
| In-plane GRP, twin skin with liner | £165 to £270 | Liner rooflight and cavity detailing |
| Multiwall polycarbonate, in-plane | £150 to £260 | Wall structure and thermal grade |
| Barrel vault on new kerb | £520 to £950 | Kerb formation and weathering included |
| Insulated composite rooflight panel | £220 to £400 | Heated and conditioned buildings |
Rates are supply-and-fit for accessible roofs in normal hours, netting included. Add for specialist access, out-of-hours, discontinued profiles and coastal upgrades. Figures are for east of England budgeting.
What a rate does include
A per-square-metre rate for standard work covers the rooflight and, on a twin-skin roof, its liner, the laps, sealant and fixings, safety netting beneath the work, removal of the old sheet and disposal. It assumes an accessible roof, normal working hours, a standard still-made profile, and no structural surprises once the roof is open. On a job that matches those assumptions, the rate multiplied by the rooflight area gives a sound budget figure.
What a rate does not include, and why it matters. The rate excludes specialist access equipment, out-of-hours premiums, discontinued-profile tooling, coastal upgrade packages, structural repair to purlins or fixing points, and AOV smoke ventilation units. On many real roofs one of these, usually access, is a large share of the total. So a rate quoted without its exclusions named is a rate that will grow. Always ask what a per-square-metre figure excludes before you rely on it.
When a per-square-metre rate misleads
A rate is an average, and averages break where the real cost is dominated by something the rate does not see.
- Difficult access. The rate assumes a reachable roof. A high roof needing a crane or a mobile platform can carry an access cost as large as the rooflights, and no per-square-metre figure captures that. This is the single most common way a rate misleads.
- Small areas. A rate assumes the access is shared across a reasonable area. On a small job the fixed access cost falls on few square metres, so the effective rate is far higher than the table. Isolated sheets do not price at the table rate.
- Heavy phasing. Splitting a roof into many small phases means paying access repeatedly, which raises the effective per-square-metre cost above a single-visit rate.
- Discontinued profiles. A moulded-to-match sheet adds tooling and a minimum order, which a standard rate does not include.
The rule of thumb: a per-square-metre rate is reliable for a large, accessible, single-phase roof with a standard profile. The further your job is from that, the less the rate tells you, and the more the survey figure diverges from it. This is why we price the firm scope by bay, where the access and phasing are captured, rather than by a blanket rate. Our warehouse rooflight replacement cost answer covers per-sheet and per-bay budgeting.
Using the rate well
The right use of a per-square-metre rate is to get a first number into a capital plan before a survey: measure the rooflight area, apply the rate for the build-up you expect, and add a sensible allowance for access and any known complications. Treat it as a range, not a price. Then let the survey replace it with a firm figure. Used that way, the rate is a good planning tool. Used as a quote, it disappoints.
What it means around Ipswich
Local warehouse and industrial roofs vary widely in height and access, from low older sheds to tall modern distribution units, so the access allowance on top of the base rate varies more here than the rate itself. On the coastal belt near Felixstowe and Harwich, add the marine upgrade. Older estates around Ipswich frequently have discontinued profiles, adding tooling. The base rate is the same across the region, but what sits on top of it is very site-specific.
What is the cost per square metre for commercial rooflights?
As a budget figure, roughly £110 to £190 per square metre for single-skin in-plane GRP, £165 to £270 for twin-skin with a liner, and £520 to £950 for a barrel vault on a new kerb, supplied and fitted on an accessible roof in normal hours. Specialist access, out-of-hours, discontinued profiles and coastal upgrades are added on top.
Why is my quote higher than the per-square-metre rate?
Usually access. The rate assumes a reachable roof and a reasonable area over which to share the access cost. A high roof, a small area, heavy phasing or a discontinued profile all push the real figure above the table rate, and none of them show in a blanket per-square-metre number. This is why the firm scope is priced by bay, where those factors are captured.
Get a rate turned into a real figure
Use the per-square-metre rates to build a budget, then let a survey capture the access and phasing and give you a figure priced by bay. That is the number that holds.
Request a survey. Read across to warehouse rooflight replacement cost, barrel vault rooflight cost, and the full commercial rooflight replacement cost guide.
Thinking about this job? We survey across Ipswich, Suffolk and north Essex and give you a fixed price before any work starts, with a 10-year workmanship guarantee.