🇬🇧 United Kingdom · Roofing · Updated 2026
How much roofing do you need to build a house in the United Kingdom?
A 150 m² single-storey house in the United Kingdom needs roughly 232 m² of roofing — about 1.55 m² per m² of floor area. That is computed from United Kingdom construction conventions, including the local wastage allowance.
Roofing quantities for a house in the United Kingdom, computed from how buildings are actually put up here rather than from a global average. The tables below run from a small 50 m² dwelling to a 400 m² family home, and the method section shows how to reproduce every figure by hand so you can adapt it to your own plan.
Roofing by house size in United Kingdom
| Floor area | Roofing required | Per m² of floor |
|---|---|---|
| 50 m² | 85 m² | 1.70 |
| 75 m² | 122 m² | 1.63 |
| 100 m² | 159 m² | 1.59 |
| 150 m² | 232 m² | 1.55 |
| 200 m² | 304 m² | 1.52 |
| 250 m² | 375 m² | 1.50 |
| 300 m² | 446 m² | 1.49 |
| 400 m² | 587 m² | 1.47 |
Single-storey. The per-m² rate falls as the house grows — a small house has more wall and roof per square metre of floor than a large one, which is why these are computed size by size rather than scaled from a single rate.
Where it goes — 150 m² house
Roof covering area 173 m² plan opened out at 35° plus 10% laps | 231.6 m² |
Fascia, barge & rainwater goods Perimeter plus gable rake | 57.5 m run |
What drives the quantity in United Kingdom
| Factor | Local value | Effect |
|---|---|---|
| Roof pitch | 35° | Pitch converts plan area to real surface: at 35° the roof is about 1.22× the plan area beneath it. |
| Eaves overhang | 450 mm | Overhang adds covering area all the way round and is routinely left out of quick estimates. |
| Laps | ~10% | Side and end laps on sheeting, or headlap on tiles. Never covered by the geometric area. |
| Climate | temperate | Rainfall intensity and UV exposure drive covering choice and gutter sizing more than load does. |
How to calculate it yourself
- 01
Take the plan area of the building and add the overhang all round (0.45 m here).
- 02
Divide by cos(35°) — a factor of about 1.221 — to get the true sloping area.
- 03
Add about 10% for laps and cutting at hips and valleys.
- 04
For sheets, divide by the cover width (not the overall width) of the profile you are buying, then round up to whole sheets of the right length.
- 05
Measure gutters, fascia and barge boards on the perimeter separately — they are priced per metre run, not per m².
Buying and site notes
- —Order sheets cut to the full rafter length where possible. Every end lap is a leak waiting to happen and adds material.
- —Fixings are not a rounding error on a large roof — count them, especially in high-wind areas where the fixing schedule is prescribed.
- —Check the gutter and downpipe sizing against local rainfall intensity, not against habit.
Get every material measured off your own plan
This page works from a representative footprint. Upload your dimensioned drawings and get the full schedule — every material, measured from your real geometry and priced in GBP (£).
Take off my drawingsRoofing in United Kingdom — frequently asked
How much roofing does a house need in the United Kingdom?
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A 150 m² single-storey house in the United Kingdom needs roughly 232 m² of roofing — about 1.55 m² per m² of floor area. That is computed from United Kingdom construction conventions, including the local wastage allowance.
How much roofing per square metre in the United Kingdom?
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About 1.55 m² per m² of floor area for a single-storey house. The figure is not linear across sizes — a small house has proportionally more wall and roof per m² of floor than a large one, which is why the table above is computed size by size rather than scaled from one rate.
What changes the quantity of roofing needed?
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Roof pitch (35°) — Pitch converts plan area to real surface: at 35° the roof is about 1.22× the plan area beneath it. Eaves overhang (450 mm) — Overhang adds covering area all the way round and is routinely left out of quick estimates. Laps (~10%) — Side and end laps on sheeting, or headlap on tiles. Never covered by the geometric area.
Is wastage included?
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Where it applies, yes — a 5% allowance is carried on the perishable materials (walling units, tiles, paint). Bulk materials like sand and stone carry handling loss instead. Ordering the theoretical quantity with no allowance reliably means a second delivery at a worse price.
How accurate is this for my own house?
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It is a planning quantity derived from a representative rectangular footprint, so it is the right order of magnitude and internally consistent — good for budgeting and for checking a supplier's list. It is not a measured takeoff of your plan. Upload your dimensioned drawings to get quantities measured off your real geometry and priced in GBP.
Are roofing prices included?
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No, deliberately. Material prices in the United Kingdom move week to week and vary by region, so a price printed on a static page would be wrong within a month. This page gives you the quantity — take that to two or three local suppliers and the price will be current and competitive.