Nour Nagy Designs

Roofing Material Calculator

Estimate the materials for a pitched or flat roof across up to three sections. Enter each section’s dimensions and your material type, add optional gutter, fascia and soffit runs, and the calculator returns coverage, underlay, fixings and edge components.

UK roofing coverage & fixings guide
Material	Coverage	Fixings
Tiles	60/m²	2 nails/tile
Shingles	8/m²	4 nails/shingle
Metal sheets	1/m²	6 screws/sheet
Underlay	37.5 m²/roll	10 fixings/m²
Ridge caps	1 per 0.5m	—
Flat membrane	20 m²/roll	1 tub adhesive/15m²

Roof type

Material type

Section 1 — length (m)

Section 1 — width (m)

Section 2 — length (m)

Section 2 — width (m)

Section 3 — length (m)

Section 3 — width (m)

Any openings? (m²)

Ridge length (m)

Gutter length (m)

Fascia length (m)

Soffit length (m)

Wastage (%)

How to use

Enter the dimensions of each roof section separately — a hipped or multi-pitch roof should be split up.
Select the covering: tiles, slates, sheets or a flat membrane.
Add the ridge, hip and verge lengths.
Enter gutter, fascia and soffit runs if you want them included.
Set the wastage allowance and read the totals.

Notes

Enter slope length, not plan length. On a 30° pitch, slope length is roughly 15% longer than the plan dimension.
Cut roofs, hips and valleys generate more waste. Allow 10% on a simple gable and up to 15% where there are hips and valleys.
Batten gauge depends on the tile’s headlap and the roof pitch. Check the manufacturer’s fixing specification for the pitch you are working at.
Underlay needs a horizontal lap; the area figure includes an allowance but check it against the roll width you are buying.

FAQs

How many roof tiles per square metre?

It depends entirely on the tile. Large interlocking concrete tiles run around 10 per m²; plain tiles at standard gauge run around 60 per m². Always work from the manufacturer’s stated cover width and gauge.

Does this work for flat roofs?

Yes. Select the membrane option and enter the area. It gives membrane, primer and fixing quantities, but not falls or drainage design.

Do I need planning permission to re-roof?

Like-for-like re-covering is normally permitted development on a house, but changing the material, the roof line or adding rooflights can change that — and listed buildings and conservation areas have their own rules. Check with your local authority before starting.

Need more than an estimate?

These tools give you a reliable starting figure. When you’re ready to turn it into a costed, fixed-scope proposal, our team works across London, Dubai and Cairo on architecture, interior design and turnkey delivery.

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