COST GUIDES
Bay window roof replacement cost: 2026 UK prices
Updated 06/26
Wondering how much it costs to repair or replace a bay window roof? Whether yours is leaking, damaged or simply looking worse for wear, this guide has you covered.
We'll explain:
Average bay window roof replacement costs for felt, fibreglass, lead and other common materials
What's included in a roofer's quote
How to decide between a repair and a full replacement
Fast Facts
Felt flat roof replacement: Around £50 per m² (materials and labour)
Lead flat roof replacement: On average £97.50 per m² (materials and labour)
Pitched roof replacement (slate/tile): Around £137.50 per m² (materials and labour)
How much does a bay window roof replacement cost?
| Repair type | Low cost per sq. m | High cost per sq. m | Average cost per sq. m |
|---|---|---|---|
| Lead flat roof | £90 | £105 | £97.50 |
| Fibreglass flat roof | £95 | £120 | £107.50 |
| Felt flat roof | £40 | £60 | £50 |
| EPDM flat roof | £80 | £90 | £85 |
| Slate or Clay tiled roof | £75 | £200 | £137.50 |
| Last updated: July 2026 Our costs are ballpark averages - get a local tradesperson to quote now | |||
The cost of replacing a flat bay window roof is that it's usually priced per square metre (m²) and most bay windows have a roof area of roughly 1.5–3 m².
But when it comes to calculating your total bay window roof replacement price, the type of material you choose is a big cost factor. So let's start there.
Bay window flat roof replacement cost: By material
Here's the most commonly used materials for a flat bay window roof replacement and their pros, cons and overall cost per m² for material and labour:
Felt:
Pros: The lowest-cost option and suits most roofs
Cons: It requires hot-flame installation, so definitely not a DIY job
Lifespan: 10–15 years
Cost per m²: Starting at £40
Fibreglass:
Pros: A modern, lightweight alternative to lead that can look similar when aged
Cons: It carries a higher upfront cost but is long-lasting
Lifespan: 25+ years
Cost per m²: Between £95 and £120
EPDM rubber:
Pros: Flexible, hardwearing and cost-effective option that lasts for many years
Cons: It's not as visually appealing as other materials and can shrink slightly over time
Lifespan: 25–30 years
Cost per m²: Starting at £80
Lead:
Pros: A popular option that gives a timeless finish
Cons: Lead flashing can attract thieves in some areas, so it's worth considering security
Lifespan: 50–80 years
Cost per m²: One of the most expensive materials, around £90 and £105
Slate or clay tiled roof:
Pros: A traditional, long-lasting finish that suits both period homes and modern properties
Cons: Heavier than other roofing materials, so the roof structure must be strong enough to support them
Lifespan: 60–100+ years (slate) or 50–100 years (clay tiles)
Cost per m²: Between £75 and £200
The costs above are per square metre and cover labour and materials for a standard bay window roof, but remember: they're approximations.
For an accurate quote, you're always best off getting a selection of quotes from local roofers near you.
Find trusted roofers near you
To find a tradesperson and price up for the job, download our free mobile app.
Bay window roof replacement cost: Job estimator tool
Not quite ready to contact a roofer, but want to learn more about the costs involved?
Try our free interactive cost calculator for an instant estimate based on your roof size and preferred material.
Job Estimate Calculator
What affects the cost of replacing a bay window roof?
Several factors push the price up or down. Here's what to check before you get quotes:
Roof size – Roofers charge per square metre, so a larger bay costs more. Most bay windows sit between 1.5 and 3 m²
Material choice – Felt is the cheapest option; lead and tiling are the most durable (and the most expensive)
Scaffolding – Required for first-floor bays; typically £22.50 per m²
Access and location – Harder-to-reach properties or London and South East postcodes typically cost more
Condition of the underlying timber – If the decking is rotten, it needs replacing before the new surface goes on. This adds to the overall cost
Flat vs pitched – Converting a flat roof to pitched costs more than a like-for-like replacement. Our flat and pitched roof cost guide weighs up both options
If the roof of your bay window is being opened up, it's the perfect time to add or upgrade the insulation. It costs much less when your roofer is already on site and can help reduce heat loss and lower your energy bills. See our guide on insulation costs for typical prices.
Cost to repair a pitched bay window roof
If you're lucky, you may only need to pay for a repair rather than a full replacement. Repairs are more common, though, for pitched bay window roofs covered with slate, clay tiles, or lead flashing.
Depending on the roof's age and condition, it may be possible to replace cracked slates individually.
However, your roofer can advise on the full extent of the work needed and whether it's better to repair or replace. More on that next.
Find a trusted tradesperson in your area
Should you repair or replace your bay window roof?
If your flat roof is approaching the end of its lifespan, replacement makes more financial sense than repeated repairs.
Felt roofs typically last 10–15 years, EPDM rubber 25–30 years, fibreglass 25+ years, and lead 50–80 years. Here's some other considerations:
When to repair:
A few cracked tiles
Small areas of slipped slate
A small hole in the felt which can be patched up
An experienced roofer can normally fix these repairs in a couple of hours at an hourly rate.
When to replace:
If the roof is leaking in multiple places
The surface is bowing
You can see damp patches inside the bay
Discovered your bay window needs structural work too? Don't worry. From bay window installation costs to underpinning a bay window, we've got all the key costs ticked off to help you budget for the work.
What's included in a bay window roof replacement quote?
Hire right, and your quote for replacing a bay window roof should cover:
Stripping and disposing of the old material
Replacing any rotten timber decking
Laying the new roof surface
Finishing the edges and flashings
A check-back visit to confirm there are no leaks
Make sure the quote is itemised so you can see whether scaffolding, materials, and labour are separated out.
How to find a roofer for your bay window
Use our quick and easy request a quote feature and we'll get experienced local roofers to contact you directly. To get accurate quotes, be as detailed as you can:
The approximate size of your bay window roof (length x depth in metres if you can measure it)
Whether the roof is flat or pitched
The current material (lead, felt, fibreglass, EPDM, or tiles)
Whether there's active leaking or just general wear
Whether you're on the ground floor or first floor (scaffolding requirement)
Hiring a good local roofer
Want to know how to hire a roofer? Here's everything you need to know and look out for when choosing a roofing professional.
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Hear from homeowners like you:
This Leicestershire homeowner hired Checkatrade-approved LRF Roofing Services for repairs to their lead roof:
Lee and team were absolutely brilliant when they came to fix some holes in our lead bay roof. From start to finish, they were professional and friendly, and really took their time to make sure the job was done well and at a fair price. Would definitely recommend and use again!
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Bay window roof replacement: Cost checklist
Before you contact a roofer, it helps to know:
Bay window roof replacement FAQs
Most bay windows have a roof area of 1.5–3 square metres, which puts the total replacement cost at around £500–£900 for felt, £750–£1,500 for EPDM rubber, £1,000–£1,800 for fibreglass, and £1,200–£2,500 for lead. Scaffolding adds £200–£400 if it's needed. Your roofer can confirm whether the job requires it.
A bay window roof is like any other roof and will eventually need to be replaced due to wear and tear. You might spot:
Damp patches in the bay
Bowing in the roof itself
Water dripping onto the sill or running down the inside of the window because of a leak
It should take no longer than a day for a roofer to repair a bay window roof. The roofer should return the following day to confirm there are no leaks.
The roof over a bay window is simply called a bay window roof or bay roof. Flat versions are sometimes called a bay canopy. They're built the same way as any flat or pitched roof, just scaled down to cover the bay window projection.
Whether or not you can claim on home insurance for a bay window depends on the cause. If the damage results from a sudden event (a storm, a fallen branch, or accidental damage) your home insurance may cover the repair or replacement. However, gradual wear and tear is almost never covered. Check your policy wording and report the damage promptly, as insurers sometimes ask for evidence that the damage wasn't pre-existing.
Replacing a bay window roof like-for-like generally doesn't need planning permission. It's treated as a maintenance repair. However, converting from a flat roof to a pitched one might need permitted development approval, particularly in conservation areas or if you're in a listed building. Always check with your local planning authority before changing the design.
Yes, you can convert a flat bay window roof to a pitched roof, though you may need planning permission if you're changing the roof's design, particularly in conservation areas or for listed buildings. For a full cost breakdown, see our guide to converting a flat roof to pitched.
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