COST GUIDES
Window sill replacement cost in the UK
Updated 07/26
If your window sills have become damaged or rotten, it's time to replace them. By the end of this guide, you'll have a rough cost estimate to replace you window sills.
Fast Facts
On average, you can expect the cost of replacing a window sill to be around £140 and £220
For a standard window sill replacement the cost is usually in the region of £40 to £55
The cost will be higher for more complex window sill replacement jobs
Window sills protect the wall beneath from the damaging effects of rain and condensation. So, if they're damaged you'll want to replace them as soon as you can.
But how much does it cost to replace a window sill in the UK? Let's find out...
What is the cost of a replacement window sill?
| Item (with labour) | Range - Low | Range - High | Average Cost |
|---|---|---|---|
| Standard window replacement sill | £140 | £220 | £180 |
| Severely rotted sill replacement with frame elements | £350 | ||
| Sash window sill replacement | £120 | £340 | £230 |
| Bay window sill per 1.2M | £185 | ||
| Edwardian bay window stone sill | £3,850 | ||
| Concrete window sill replacement (average sized) | £148 | ||
| Last updated: July 2026 Our costs are ballpark averages - get a local tradesperson to quote now | |||
The average total window sill replacement cost in the UK is around £140 and £220 for a wooden or uPVC sill.
That price typically includes the supply of all materials and the labour cost of removing your old sill and installing the new one.
The cost to replace an exterior window sill - especially if it's made of stone or concrete - will generally cost much more than an interior sill.
For a standard window sill replacement, a handyman would typically charge around £40 to £55 for the job.
For prices of other jobs that a handyman will do, check out our guide to handyman prices.
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Windowsill replacement costs by material
Timber or wood window sill replacement cost
A standard timber or wood window sill costs an average of £180 to replace.
This is assuming it's a standard replacement job. If your previous wooden sill is severely rotted, that will cost you quite a bit more.
uPVC window sill replacement cost
A uPVC window sill is the cheapest kind to replace, again averaging just £180 with labour and materials included.
Concrete window sill replacement cost
The average concrete window sill replacement cost is around £148per window installed (charged by the linear foot).
For windows with concrete window sills, you'll need a tradesperson who has experience working with concrete.
It's also worth noting that you usually order concrete window sills as pre-cast lengths.
Edwardian bay window stone window sill replacement cost
Replacing an Edwardian stone window sill starts around £3,850.
If you have an Edwardian bay window in your home that features a stone window sill that needs replacing, you're going to have a costly project on your hands. You'll need a stonemason to carry out the work and that doesn't come cheap.
Factors affecting window sill replacement costs
That price for replacing your window sill will depend on various factors, including:
The type and size of window sill being replaced
The material the sill is made from
If there's any structural damage to rectify
The complexity of the job (and how long it takes to complete)
Where you live
For example, the average price for replacing a standard timber or uPVC window sill is less than the average concrete window sill replacement cost.
It's also worth noting that tradespeople in London and the South East of England tend to charge more than in other parts of the country.
You can expect to pay more for complex sill replacement jobs. Those jobs need a skilled tradesperson to do the job properly and avoid the risk of further damage in the future.
Get an estimated quote
Use the Checkatrade job estimate calculator to get a rough idea of how much your window sill replacement may cost.
Just enter a few details about the task at hand, such as the type of sill you need replacing, and let the tool dig into our pricing data to give you an approximate quote.
Job Estimate Calculator
How much does sash window sill repair cost?
The average hourly rate for a tradesperson to repair a sash window sill is around £32.50 per hour.
If your sash window sill is only partly damaged, then you may be able to repair your existing still – rather than replacing the whole sill.
The total cost will depend on how long it takes to remove, repair and refit the window sill.
To help you compare, the cost of replacing a sash window sill with a new one is around £120 to £340.
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Other window sill repair costs
Bay window sill repair costs
A bay window sill costs around £185 per 1.2 metres.
Repairing a rotten bay window sill will typically cost more than a standard window sill, and will require a highly skilled service – particularly if you have wooden period windows.
Costs will vary depending on the work required and material and age of the window.
If you have a period property you will need a quote from a specialist to gauge the best approach.
The restoration and repair project often requires a complete repair and rebuild of the bay window.
Rotten window sill: When to repair vs replace
On average, the material costs for that work are in the region of £350+.
The general rule is that you should replace the whole sill if more than 10% of the sill is rotten. For just a small amount of damage, a repair may do the job. See how much window sill damage repair costs in our full guide.
If a window sill has suffered serious damage and been left for a long time, there could be serious consequences for the structure of the surrounding window frame and walls, such as dry rot.
If this has happened you may need to replace the whole window frame and carry out repair work to the brickwork or walls underneath or surrounding the window.
Can you replace a window sill without removing the window?
In many cases, yes. A skilled tradesperson can replace an exterior or interior window sill without removing the window frame, as long as the frame and surrounding structure are sound.
However, if the rot or damage has spread into the frame, the window usually needs to come out to make a proper repair. Your tradesperson can assess this before starting the job.
Your window repair may uncover other work that needs doing. At Checkatrade, you can find checked and reviewed window fitters, builders, plasterers, carpenters, and more - all in one place, all committed to quality and a job done right.
Find trusted window sill replacement services near you
It's always best to hire a tradesperson to replace your window sill, especially if you have period windows or stone sills that require specialist skills.
Ready to start? Enter your postcode in the box below to browse a list of checked tradespeople who operate in your area.
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You can also post your job to hear back from window sill services near you, or download the Checkatrade app!
FAQs
It's possible, but it depends on how extensive the rot is. If it's a small patch of localised rot then you can usually fix it up using an epoxy repair kit.
However, if more than 10% of the window sill is rotten then you should replace the whole sill.
A standard window sill replacement costs between £140 and £220, including supply and labour. Most homeowners find it a reasonable price to pay for the protection it gives against damp and structural damage.
Complex jobs (such as stone sills, period properties, or rotted frames) cost significantly more.
Yes, in most cases. If the window frame and surrounding brickwork are undamaged, a tradesperson can swap out the sill without touching the rest of the window or frames.
That said, if the rot has spread into the frame, you may need a bigger repair or full replacement.
Yes. Window fitters, joiners, and handypeople can all replace window sills, depending on the material and complexity. Stone sills need a stonemason.
For most standard timber or uPVC sills, a joiner or handyperson is the right call.
It's not always advised. Interior uPVC sills can be a DIY job if you're confident working with power tools and sealant.
However, exterior sills, timber sills, and any job involving rot into the frame are best left to a tradesperson. Failing at weatherproofing can cause damp problems later.
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