Roofing Calculator

Work out exactly how many tiles, slates or felt rolls you need — and get a 2026 material cost estimate.

Calculate Roofing Materials

Enter your roof slope dimensions and tile type to get your materials list and cost estimate.

Measure along the ridge (horizontal length of the roof)
Measure from ridge to eaves along the slope

Your Roofing Materials

Roof Area
Tiles Needed
inc. 10% extra
Felt Rolls
rolls
Est. Material Cost
materials only

Get Your Free UK Home Improvement Cost Guide

We'll send you our 2026 UK materials price guide covering roofing, concrete, brickwork and more — so you can budget accurately before you buy.

Where to Buy Roofing Materials in the UK

Once you know your tile count, here's where to compare prices and buy. Always confirm stock before ordering in bulk.

SupplierWhat They StockBest For
Wickes Concrete tiles, roofing felt, battens, fixings Trade pricing, click & collect
B&Q Roof tiles, slates, breathable membrane UK-wide stores, same-day collection
Amazon UK Self-Adhesive Asphalt Roof Shingles 18pcs — top-rated shed roofing Most reviewed roofing product, Prime delivery

Links marked above are affiliate links — we may earn a small commission at no extra cost to you. We only link to reputable UK suppliers.

UK Roofing Tile Coverage Reference (2026)

Different tile types have very different coverage rates. Use this table as a quick reference when planning your project.

Tile Type Tiles per m² Price per Tile (2026) Typical Pitch
Concrete Interlocking~10£1.2017.5° minimum
Clay Plain Tile~60£0.6035° minimum
Natural Slate (600×300mm)~20£2.5020° minimum

Note: Prices are approximate 2026 trade/retail averages. Costs vary by region, supplier, and tile profile. Always get at least 3 quotes before purchasing in bulk.

How to Use This Roofing Calculator

Step 1: Measure the Roof Length

Stand at the gable end and measure the horizontal length of the roof from end to end along the ridge. For a standard semi-detached house this is typically 5–9 metres.

Step 2: Measure the Slope Length

Measure from the ridge down to the eaves along the surface of the roof slope (not the horizontal span). This is best done from inside the loft or using a long tape measure on the roof surface. For a typical UK house, this is 4–6 metres per slope.

Step 3: Select Number of Slopes

A standard gable or hip roof has 2 slopes. A lean-to extension or mono-pitch roof has 1 slope. If your roof has more than 2 slopes (e.g. an L-shaped roof), calculate each section separately and add the results together.

Step 4: Choose Your Tile Type

Concrete interlocking tiles are the most common choice for new builds and re-roofs in the UK due to their low cost and durability. Clay plain tiles are traditional and aesthetically superior but require a steeper pitch. Natural slate is premium and long-lasting but more expensive.

Frequently Asked Questions

How many roof tiles do I need per square metre?
The number of tiles per square metre depends on the tile type. Concrete interlocking tiles typically cover at around 10 tiles per m². Clay plain tiles are smaller and need approximately 60 per m². Natural slate typically requires around 20 slates per m², depending on the size and headlap used.
How much does it cost to tile a roof in the UK in 2026?
In 2026, material costs for UK roofing are approximately: concrete interlocking tiles at £1.20 each, clay plain tiles at £0.60 each, and natural slate at £2.50 per slate. Labour costs are separate and typically range from £50–£80 per m² for a full re-roof. This calculator covers materials only.
Do I need roofing felt under the tiles?
Yes. Roofing underlay (felt) is required under all roof tiles in the UK. It acts as a secondary barrier against wind-driven rain and moisture. Modern breathable membranes are preferred over traditional bitumen felt as they allow moisture vapour to escape from the roof space, reducing condensation.
How much overlap is needed for roofing felt?
Roofing felt should overlap by a minimum of 150mm (15cm) at horizontal laps and 100mm (10cm) at vertical laps. This calculator accounts for a 150mm overlap when calculating the number of felt rolls needed. Standard rolls are 15m long and 1m wide.
Should I add extra tiles for breakages and cuts?
Yes. Always order at least 10% extra tiles to account for breakages during installation, cuts at hips and valleys, and future repairs. This calculator automatically includes a 10% wastage allowance in its output.
What is the minimum roof pitch for concrete interlocking tiles?
Most concrete interlocking tiles require a minimum roof pitch of 17.5 degrees, though some profiles can go as low as 12.5 degrees with additional underlays. Clay plain tiles typically require a minimum pitch of 35 degrees. Always check the manufacturer's specification for the specific tile you are using.