Roof Replacement Cost Guide: How to Build an Accurate UK Estimate

Roof replacement cost cannot be estimated accurately from floor area alone. The price depends on true roof area, covering system, access, strip-off, deck condition, insulation, flashings, rainwater goods, labour, waste, and the details that make one roof slower than another.

For a quick starting point, use the free roof replacement cost calculator. For a quote you can rely on, build the estimate from measured quantities and a written scope.

Why roof replacement prices vary so much

Two houses with the same footprint can have very different roof costs. One may have a simple two-plane gable with easy scaffold access. The other may have hips, valleys, dormers, rooflights, parapets, several levels, restricted loading space, and damaged decking.

The main cost drivers are roof size and pitch, shape, existing covering, new specification, access, deck condition, insulation, flashings, rainwater goods, labour, disposal, hidden conditions, and site restrictions.

A useful estimate makes these drivers visible instead of hiding them inside one rate per square metre.

Step 1: define the replacement scope

Clarify whether the work includes full removal, structural repairs, deck replacement, underlay, battens, covering, ridge and edge systems, valleys, flashings, rooflights, ventilation, insulation, rainwater goods, scaffolding, waste, and making good.

A ?new roof? can describe very different scopes. Write the inclusions and exclusions before pricing.

Step 2: calculate true roof area

Measure each roof plane and adjust plan area for pitch. A 100 m? horizontal footprint does not equal 100 m? of pitched roof covering.

Use the free roof area calculator and roof pitch calculator, or follow how to measure a roof for materials.

Measure linear components separately, including ridge, hips, valleys, eaves, verges, abutments, parapets, gutters, and downpipes.

Step 3: price strip-off and disposal

Removing the old roof has its own labour, access, protection, and disposal costs.

Consider covering type and weight, number of layers, fixing method, fragile or hazardous materials, loading, waste separation, skips, transport, disposal, temporary protection, and daily weathering.

Do not assume disposal is a small percentage of the new roof. Quantify the work and use current local disposal rates. If potentially hazardous materials are present, stop and follow the correct survey, handling, and legal process.

Step 4: build the material schedule

Use the selected product specification to calculate main covering, underlay, battens, deck, insulation, ridge, hips, verges, eaves, valleys, flashings, fixings, ventilation, rainwater goods, and waste by material group.

The roofing material list gives a complete checklist. The free roofing material calculator helps turn measured area into quantities.

Request current supplier prices for the exact product, colour, finish, pack size, and delivery location. Online guide prices are not a substitute for a live supplier quotation.

Step 5: calculate labour by activity

A single labour rate per square metre can miss the slow parts of the job.

Break labour into site setup, strip-off, deck work, underlay and battens, covering, ridges and edges, flashings, rainwater goods, cleaning, and handover.

Estimate crew size and duration for each activity. Include supervision, handling, realistic programme risk, and time spent on complex details.

For a wider pricing method, read how to price a roofing job.

Step 6: add access, plant, and site costs

Common items include scaffolding, edge protection, hoists, cranes, telehandlers, temporary roofs, welfare, parking, permits, restricted deliveries, landscaping protection, travel, and accommodation.

Obtain quotes for major access and plant rather than guessing.

Step 7: handle unknown conditions openly

A replacement roof can hide damaged timber, failed deck, wet insulation, poor ventilation, or previous work that does not match drawings.

Use one of three approaches:

• Confirm condition through survey or opening-up before final price.
• Include a defined provisional allowance.
• State a unit rate for additional work if discovered.

Explain how approval will work. This is clearer than adding a hidden contingency or pretending the risk does not exist.

Worked estimate structure

This format helps contractor and customer understand where the price comes from without exposing every internal cost.

Homeowner questions when comparing quotes

Check whether each quote includes the same scope:

• Is scaffolding included?
• Is strip-off and disposal included?
• Which covering and manufacturer are specified?
• Are underlay and battens included?
• How are rotten deck or timber repairs handled?
• Are ridges, valleys, flashings, and ventilation included?
• Are gutters and downpipes included?
• What is excluded?
• What warranty or guarantee applies, and who provides it?
• What payment stages are proposed?

The cheapest total can become expensive if major items are missing.

Common estimating mistakes

• Pricing from house floor area
• Using one square-metre rate for every roof
• Forgetting pitch adjustment
• Ignoring edges, junctions, and penetrations
• Using old material prices
• Underpricing strip-off and waste
• Treating access as an afterthought
• Hiding unknown conditions
• Missing small system components
• Applying margin only to selected cost lines

From estimate to professional quote

The free roofing quote calculator and free quote generator help turn costs into a customer-facing document.

QuoteCore+ connects measurement, Smart Components?, pricing, quotes, acceptance, material orders, and invoices. Watch Roofing Quoting Software That Actually Works for an overview.

Frequently asked questions

How much does a new roof cost in the UK?

There is no reliable single figure without roof area, pitch, shape, specification, access, and condition. Use a measured estimate and current local supplier and labour rates rather than a national average alone.

Is roof replacement priced per square metre?

Square-metre rates can help with early comparisons, but a final estimate should measure details, access, strip-off, waste, and risk separately. Complex details can cost more than the field area suggests.

Does a roof replacement quote include scaffolding?

It should say clearly. Never assume scaffolding, lifting, permits, or protection are included. Compare written inclusions across quotes.

What happens if rotten timber is found?

The quote should explain whether repairs are included, provisional, or charged at an agreed unit rate. Document and approve additional work before proceeding where practical.

How can a contractor quote roof replacement more accurately?

Use a checked takeoff, product-specific schedule, activity-based labour estimate, current supplier prices, named access costs, and clear allowances for unknown conditions.

Start with the free roof replacement cost calculator, then use roofing quoting software when you want the complete workflow connected.