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myWindow Sill Replacement Cost
At a Glance
- The average window sill replacement cost is around £155 in the UK.
- Most jobs take 1.5 to 3 hours to complete.
- A breakdown of what different types of new window sills cost in 2026, as well as a look at what impacts the prices you're quoted.
- Expert advice from tradespeople on MyJobQuote about window sill replacements.
- How to find and hire a window sill fitter using MyJobQuote.
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£155
Table of Contents
- How Much Does Window Sill Replacement Cost?
- Labour Cost to Replace a Window Sill
- What Impacts Window Sill Replacement Costs?
- What's Involved in a Window Sill Replacement?
- Types of Window Sill Replacement
- Should You Repair or Replace Your Window Sill?
- Checklist: Hiring Contractors for Window Sill Replacement in the UK
- FAQs
How Much Does Window Sill Replacement Cost?
The cost of replacing a window sill will vary primarily based on the type of window sill replacement and the size of the installation area.
The cost of having a PVC window sill replaced is generally between £75 and £175, with the cost rising to £150 to £255 for a stone window sill.
What type of window sill replacement do you need?
PVC
4 votes - 21%21% of votes
Stone
3 votes - 16%16% of votes
Wood
9 votes - 47%47% of votes
Concrete
2 votes - 11%11% of votes
MDF
1 votes - 5%5% of votes
19 votes
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Replacing a wood window sill usually costs around £80 to £195, whereas a concrete window sill replacement costs £105 to £230. You'd be looking at paying £95 to £195 to replace an MDF window sill.
Beyond this, the two main factors that impact quotes are ease of access to the window sill and where you're located in the UK.
My bay window tiled sill is broken. Can this be replaced with either PVC or wood? And if so, how much would it cost?
"It can be replaced with uPVC depending on the depth of the sill. It can cost £100 to £150 for labour and materials."
Replacement Window Sill Price List
| Type of Window Sill Replacement | Total Cost |
|---|---|
| PVC | £75–£175 |
| Stone | £150–£255 |
| Wood | £80–£195 |
| Concrete | £105–£230 |
| MDF | £95–£195 |
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Window Sill Prices by Window Type
Window sill prices also vary by window type: sash windows typically cost £120 to £340, bay windows around £185 per 1.2-metre run, and casement windows are priced the same as the material table above.
| Window Type | Typical Cost | Basis |
|---|---|---|
| Casement | £75–£255 | Per sill (see table above) |
| Sash | £120–£340 | Per sill |
| Bay | £185 | Per 1.2m run |
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Sash windows cost more due to the box-frame construction and trickier access. Bay windows often need more than one length of sill across the bay, so the total for the job usually comes in higher than the per-run figure alone.
Labour Cost to Replace a Window Sill
The labour cost of a window sill replacement (for any material) is between £60 and £135 for 1.5 to 3 hours of time. This is based on average labour charges of about £25 to £45 per hour across the UK for this type of job.
(The reason for the £60 figure is that even with 90 minutes of work, most fitters charge a minimum of around £60 to £80 for a short visit.)
This means that, roughly, around 60% of the cost for a window sill replacement goes towards labour.
Keep in mind: replacing a particularly large window sill or one that is complex to deal with for other reasons (e.g., difficult to reach) may take longer than this.
What Impacts Window Sill Replacement Costs?
When it comes to replacing a window sill, there are a whole host of factors to take on board. Let's look at these cost-affecting factors in more detail.
- Type of Window Sill Replacement — The cost of replacing a window sill primarily depends on the type you opt for. This would mostly be down to the material used. However, in addition to the materials used, the design of the window sill can also impact the replacement window sill cost.
- Size of Installation Area — The size of the window sill replacement will also matter. The larger the window sill, the higher the supply price will likely be. In addition, a larger window sill may take a bit longer to install, which can raise labour costs.
- Location in the UK — Location plays a role in what you can expect to pay, with the labour cost of a window sill replacement typically sitting above the national average in the southeast and lower in the north, Scotland, and Northern Ireland. That said, the difference is not likely to be huge for a job of this size.
- Ease of Access — How accessible the window area is could also shape your total bill. The easier it is for a professional to access the work area, the quicker the task will be. Typically, a faster job translates into a lower labour price.
- Hidden Problems — If pulling out an old sill reveals more than you bargained for, the fitter may need to repair or replace sections of the frame, treat the rot, or re-plaster the area. With stone or concrete window sills, cracks often need an epoxy repair or full replacement. A rotten sill can cost more than a straightforward swap.
- Custom Sizes and Profiling — Non-standard depths/lengths, bullnose edges, returns into reveals, templating curved bays, or scribing to out-of-true walls add time. Pre-finished or made-to-measure pieces can reduce on-site shaping but may raise supply cost.
I have an internal PVC window that might need replacing. If the damage can't be polished out, how long would it take to replace and how much it cost (including materials)? Size of window is 35"x6 and its PVC white sill (standard).
"This would be a fairly quick job. I would expect to pay around £100 including materials"
What's Involved in a Window Sill Replacement?
Changing a window sill isn't quite as undemanding as you might think. The old one has to come out very carefully, then the surface underneath needs putting right. Plus, the new sill has to be fitted and sealed in the right way so water can't get in.
Not sure you have the skills (or the patience)? It's well worth getting a professional in instead. And it's a good idea to compare a few quotes before you book someone in.
Before the Job
- Survey and measurements — Check the width, depth, and that the reveal is square, noting any trims or horns that need matching.
- Condition check — Look for damp, blown plaster, or soft timber, and agree any substrate repairs before fitting.
- Spec and finish — Choose material, edge profile, and overhang. For externals, plan a fall away from the window and a drip groove.
During the Job
- Careful strip-out — Old sill and fixings are removed without damaging the frame.
- Make good and level — The bearing surface is repaired and levelled, and any rot treated.
- Fix and seal — The sill is bedded, fixed, and sealed to the frame and walls. Externals get a fall, drip groove, and finish coat as needed.
After the Job
- Final checks — Confirm level, joints, seals, and clear drip groove. Ensure trickle vents aren't blocked.
- Curing and clean-down — Allow adhesives, caulk, and paint to cure before loading the sill.
- Handover — You'll get care notes and confirmation of any substrate repairs completed.
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Types of Window Sill Replacement
If you're not entirely sure what type of window sill you'd like to have installed, this section is for you!
Here, we will look at window sill replacement options such as PVC, stone, and wood, discuss their pros and cons and remind you of their average supply prices.
The table below shows just the cost of supplies (excluding any labour).
| Type of Window Sill | Supply Cost |
|---|---|
| PVC | £15–£40 |
| Stone | £90–£120 |
| Wood | £20–£60 |
| Concrete | £45–£95 |
| MDF | £35–£60 |
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PVC Window Sill Cost
These window sills are a popular choice and come in a wide range of sizes, finishes, and colours, including options designed to replicate more expensive materials like stone. Supply costs average £15 to £40.
Pros
- ✔ Moisture and sunlight resistance.
- ✔ Durable with low maintenance requirements.
- ✔ Protects against heat and water.
Cons
- ✖ Cheap PVC materials can contain formaldehyde.
- ✖ Lower load limit than many stronger materials.
Stone Window Sill Cost
Natural stone window sills have an estimated supply price of £90 to £120 and offer a beautiful aesthetic, the most longevity out of any of the choices discussed here, and a wide range of colours and styles to choose from.
Pros
- ✔ High aesthetic value and wide choice of styles.
- ✔ Longest lifespan of any material on this list.
- ✔ Can add value to your property.
Cons
- ✖ Cracks and scratches can appear over the years.
- ✖ Unsuitable for prolonged water exposure.
- ✖ Paint and acidic liquids can cause damage, particularly on marble.
Wood Window Sill Cost
Timber window sills are fairly commonplace and have been in use for generations. Wooden window sills have an average supply cost of £20 to £60 and can be left natural or painted to suit your home.
Pros
- ✔ Long-lasting and easy to source.
- ✔ Can add a degree of insulation to your home.
- ✔ Can be painted to match your décor.
Cons
- ✖ Prone to wood rot.
- ✖ Requires ongoing maintenance.
Wooden interior window sill beneath bay window in upstairs bedroom has a bulge in the inside corner. The window is double glazed and secondary glazing has also been installed. The area isn't damp and the bulge is firm to the touch and doesn't move, even when I press it. Anyone have any advice?
"Sometimes in old property, the brickwork sort of collapses a bit under bay windows. This may have been plastered over at some point or the plaster has bulged out. Unfortunately the only way to know what is going on is to remove the plaster back to the brickwork...then you'll see."
MDF Window Sill Cost
MDF window sills are in the same category as particleboard window sills, with MDF standing for medium-density fibreboard. MDF window sills have a supply cost of about £35 to £60, and come primed and ready to paint in standard window-board widths.
Pros
- ✔ Most affordable option on this list.
- ✔ Smooth finish, easy to paint.
Cons
- ✖ Less suited to damp or humid conditions.
- ✖ Less durable than solid wood.
Concrete Window Sill Cost
Concrete window sills are a long-lasting choice, particularly on older UK properties where they have been in use for many years. They are suited to outdoor exposure and, unlike timber, will not rot. The supply cost of a concrete window sill is typically £45 to £95.
Pros
- ✔ Durable and well suited to outdoor exposure.
- ✔ Will not rot.
- ✔ Can be painted to match your property.
Cons
- ✖ Heavy, which can add complexity to installation.
- ✖ Concrete sills can develop cracks over time.
- ✖ Joints and sealant need to be kept in good condition.
Should You Repair or Replace Your Window Sill?
Repairing your window sill is usually worth it if:
- The damage is a small crack, chip, or worn sealant, not structural failure.
- The sill is still solid underneath and just needs resealing, filling, or a patch repair.
- Repair costs come in well under the price of a full replacement.
- It's an external stone or concrete sill with only localised damage.
Replacing it usually makes more sense if:
- The sill is rotten, cracked right through, or crumbling.
- Water is getting in behind it, causing damp or affecting the wall below.
- It's already been repaired once and the same problem has come back.
- You want to change material, or the original sill was a poor fit.
Checklist: Hiring Contractors for Window Sill Replacement in the UK
When hiring a professional to install a window sill, there are some pointers worth considering first. These will help give you the best chances of securing good value for money and finding the best person for the job in your area.
Use this quick checklist before you book a window-sill fitter on MyJobQuote:
- Are they the right trade for your sill? Timber/MDF = carpenter or joiner. Stone/concrete = stonemason. External uPVC sills = window fitter. Check their MyJobQuote profile matches the material you need.
- Have they done near-identical jobs? Ask for recent photos of like-for-like work (internal vs external, bay returns, curved profiles). You'll find examples and reviews on their MyJobQuote page.
- Is the quote itemised? It should show: labour time, sill type/size, small materials (adhesive, fixings, sealant), finishing (primer/paint/caulk), making-good (plaster patching), and any access kit (tower/scaffold).
- Is waste removal included? Confirm they'll take away the old sill, packaging, and rubble, not just "fit and leave".
- Do they carry public liability insurance? It's not a legal must, but it protects you if something goes wrong.
- Do they offer any guarantees or aftercare? Ask what's covered if joints open up or the finish fails in the first few weeks.
What would be the best way to clean paint off window sills and take this back to the original stone?
"The best way is to agitate the paint lightly with a brass brush, apply a good quality paint stripper, then agitate that with the brass brush. Wash off with plenty of water as the stripper may turn the paint brown if it's a old lead paint. Depending on how many coats of paint have been applied, you could use a metal scraper to lift if off."
FAQs
Do I Need Planning Permission or Building Regulations to Replace a Window Sill?
No, not for a straight like-for-like swap. You won't usually need planning permission or Building Control. It only becomes a formal process if you alter the window opening or structure, or if the property is listed or in a conservation area. For more involved jobs, the Planning Portal has full guidance on building regulations for doors and windows.
Do You Have to Remove the Window to Replace the Sill?
No. In most cases the window itself stays in place. The sill is a separate component that a fitter can cut out and remove without taking out the window, though trim or casing may need to come off temporarily. Full window removal is only necessary if the frame itself is being replaced too.
Can I Replace a Window Sill Myself?
If you're a capable DIYer and just replacing the existing internal sill, you can probably tackle it. You'll need to remove it carefully, make the surface good, then fix, seal, and paint. Take your time and follow the product instructions.
When to call a pro: external stone/concrete sills, rotten or damaged substrate, awkward bay windows, or anything that needs masonry repairs or shaping. Those jobs are easy to get wrong and can lead to leaks.
How Long Does a Window Sill Replacement Last?
It depends mainly on material. uPVC sills don't rot, rust, or fade and need very little upkeep, while wood sills need periodic repainting or resealing to prevent moisture damage. Stone and concrete sills are built to withstand UK weather with minimal maintenance. Keeping the seal intact around the edges matters more than the material for how long any sill lasts.
Is There a Difference Between a PVC Window Sill and a uPVC Window Sill?
While both are similar, there is a distinction between PVC and uPVC window sills. PVC stands for Polyvinyl chloride. As for uPVC, the U stands for unplasticised. This means that it simply lacks the added materials contained within PVC. uPVC is sometimes referred to as rigid plastic.
What Is the Best Type of Window Sill?
This would depend on what qualities you care most about when it comes to a window sill installation. However, natural stone is arguably the overall best option due to its longevity and aesthetic value. Natural stone window sills can last a lifetime. They are also resistant to humidity and sunlight while being low maintenance too.
Is a Window Ledge or Cill the Same as a Window Sill?
Yes. Window ledge, cill, and window board all refer to the same part: the horizontal ledge at the base of a window. "Sill" and "ledge" are the everyday names, while "cill" is the spelling used in UK building and trade documentation for the same thing.
Does It Cost More to Replace a Sash Window Sill?
Sash window sill replacements can cost more than a standard window sill replacement. The added complexity of working around a sash window frame and the tricky access to the sash window can affect the overall cost.
The box frame construction of a sash window means there is less room to manoeuvre when replacing the sill, and staff beads or parting beads may need to be carefully removed and refitted without damage.
