COST GUIDES
Sill damage repair cost: 2026 UK prices
Updated 07/26
Have you noticed damage to your window sills? Whether it's rot, cracks or chipped sections, getting it fixed early stops the problem spreading to the frame.
Here's what sill repairs cost in 2026.
Fast Facts
The average hourly rate for window sill damage repair is around cost £32.50 per hour
If you need to replace your window sill it will cost in the region of £145
For door sill repairs, you'll be looking at a cost of about £85
How much does sill damage repair cost?
| Type of repair | Low cost | High cost | Average cost |
|---|---|---|---|
| Window repair costs per hour | £25 | £40 | £32.50 |
| Cost of replacing wood window sill | £110 | £180 | £145 |
| Door sill repair costs | £60 | £110 | £85 |
| Last updated: July 2026 Our costs are ballpark averages - get a local tradesperson to quote now | |||
Data verified by our professional estimators
Estimators are CIOB & RICS members
In a nutshell, sill repair typically costs £25–£40 per hour for labour. A wood window sill replacement costs £110–£180 in total, and a door sill repair costs £60–£110.
But when working out the overall cost, there are some additional cost factors to consider. Let's get into it.
How much does door sill repair cost?
A door sill (also called a door threshold) typically costs £60–£110 to repair, depending on whether it's wood, uPVC or aluminium and how bad the damage is.
Door sills take a lot of wear from foot traffic, so they're one of the more commonly repaired sills.
A cracked or split wooden threshold can often be filled and sanded. A badly rotted one needs replacing entirely. Meanwhile, uPVC and aluminium thresholds are usually replaced rather than repaired.
If the door frame also needs attention, see our guide to door frame replacement costs. For sliding or bifold doors, see patio door replacement costs.
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How much does window sill replacement cost?
Replacing a wooden window sill costs £110–£180 on average, including materials and labour. The price depends on the sill length, timber type and access.
If the sill is beyond saving (typically when rot has worked into the frame), replacing it is the better option.
A good tradesperson will check the surrounding frame for damp before fitting the new sill to stop the problem returning.
Check out our dedicated guides to UPVC sash window prices and sash window refurbishment prices to learn more about costs.
What affects the cost of sill repair?
The cost of sill repair depends mainly on what the sill is made from.
Wooden sills are usually the cheapest to patch but can be too rotten to save. Concrete sills are often a quick, low-cost fix for small cracks. uPVC sills rarely need repairing: if one's damaged, it's usually cheaper to replace the whole sill than patch it.
It's also worth considering:
Extent of damage: Surface cracks cost less than full rot or structural failure
Sill length: A longer sill takes more time and material
Access: Ground-floor sills are easy to reach; upper-floor sills may need ladders or scaffolding
Location: Rates in London and the South East tend to be higher due to demand
For an exact quote, you're always best off contacting a tradesperson directly.
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Sill damage repair cost calculator
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Signs you need sill damage repair
Window and door sills are exposed to the weather all year round, so it's normal for them to show signs of wear over time. Look out for:
Cracks or splits: Small cracks can let water in, causing the damage to worsen over time
Rotting timber: Soft, spongy or crumbling wood is a sign of rot
Peeling paint or flaking finish: A sign moisture has penetrated the sill, especially on timber
Water stains or damp indoors: Marks around windows or doors may mean the sill is no longer keeping water out
Loose or unstable sills: A sill that moves or has started pulling away from the frame could be a hazard
Mould or mildew growth: Persistent mould around a window or door can be a sign that moisture is getting in through a damaged sill
Visible gaps around the sill: Failed sealant or gaps between the sill and frame can allow draughts and water to enter your home
Spotting damage early can help prevent water ingress, rot and more expensive repairs later down the line.
If you notice any of these telltale signs, it's best to get a window fitter or carpenter to sort it.
That said, sometimes a small DIY repair might do the job. That's up next.
Can you repair a sill yourself?
Small cracks in a concrete sill are a fair DIY job: clean it out, fill with exterior-grade filler and repaint. But rotten wood, and anything structural like a door threshold, is best left to a professional.
Bodged repairs that trap moisture do more damage in the long run. If in doubt, call in a specialist.
How to find a sill repair specialist near you
Use our quick and easy request a quote feature and we'll get checked and reviewed sill repair specialists to contact you directly. Or contact a tradesperson below.
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Sill damage repair cost checklist
FAQs about sill damage repair
Labour runs from £25 to £40 per hour. A full wood sill replacement typically costs £110–£180, including materials.
Minor sill patching takes under an hour. Replacing a full sill, including drying and painting time, usually takes half a day.
Yes, if the damage is caught early, it's worth repairing a window sill. Rotten or cracked sills let moisture into the frame and surrounding wall. A small repair now is much cheaper than replacing the frame later.
Minor scratches and small chips can be filled with uPVC repair filler, but deeper cracks or breaks usually mean it's cheaper to replace the sill outright. uPVC is not as easily patched as wood or concrete.
A replacement uPVC sill typically costs less than an equivalent wood sill because there's no risk of rot and less labour involved. Get a quote from a window specialist for an exact price, as it depends on the size and style of your window.
A door sill and a door threshold are the same thing. 'Sill' and 'threshold' are used interchangeably for the strip at the bottom of a door frame that seals the gap between the door and the floor.
To fix a rotted door sill, you'll need to cut out the rotten section and treat the surrounding timber with wood hardener. If more than a third of the sill is affected, replacing the whole threshold is more cost-effective. A skilled carpenter can usually complete this in a couple of hours.
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