Window Sill Replacement Cost

Do you need a window sill replaced in your home?

This complete price guide will cover all you need to know about replacing window sills and how much they cost, including labour fees and material costs.

Check out the guide below for more information.

replacing window sill


Depending on the complexity of the job, it usually takes: 1.5 to 3 hours


How Much Does a 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 £45 and £115, with the cost rising to £120 to £195 for a stone window sill.

Replacing a wood window sill usually costs around £50 to £135, whereas a concrete window sill replacement costs £150 to £255. You’d be looking at paying £40 to £95 to replace a MDF window sill.

Other cost factors include ease of access and where you live. Your location is a cost-affecting factor since labour prices differ across the UK.

Window Sill Replacement Prices

PVC £30 to £75 £15 to £40 £45 to £115
Stone £30 to £75 £90 to £120 £120 to £195
Wood £30 to £75 £20 to £60 £50 to £135
Concrete £30 to £75 £120 to £180 £150 to £255
MDF £30 to £75 £10 to £20 £40 to £95
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Supply Only Costs

Moving on to just the cost of supplies excludes the labour price and would be what you’d pay if purchasing the replacement window directly from a retailer. This section is especially relevant for those who want to undertake the work DIY since the supply costs would be the only expense you’d be looking at.

The supply costs are as follows:

  • PVC: £15 to £40
  • Stone: £90 to £120
  • Wood: £20 to £60
  • Concrete: £120 to £180
  • MDF: £10 to £20
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Additional Costs

If hiring a professional to replace a window sill, it could be a good opportunity to have additional work undertaken on the same day or partly on the same day and continuing into further work days if required.

This could be both convenient and save you a bit of money overall. Let’s look at some relevant jobs worth looking at to accompany a window replacement.

New Windows

Having a new window installed along with a window sill replacement is an obvious go-to additional job. Having a single window replaced (such as the one where you are having the window sill replaced) would likely cost £500 to £2,000.

new windows

Prices can vary greatly depending, mostly on the type of window being used, although the size would also be an important cost factor. Hardwood windows are among the most expensive options, whereas uPVC windows are more budget-friendly. Having a single window replaced could easily fit within the same work day as replacing a window sill.

But what if you want to have several windows replaced?…

In this case, the following price estimates would apply:

  • 4 Casement windows for a terraced home: £2,000 to £2,250
  • 8 Windows for a semi-detached home: £3,500 to £4,000
  • 12-15 Windows for a detached home: £5,100 to £5,900

Having between four and fifteen windows installed should take between a full work day and a day and a half. As a result, several window installations, along with a window sill replacement, would probably need a second work day.

It could be the case that most of the work can be completed on the first day with just a few hours of work for the second day, or in some scenarios, you may even look at close to two full days of labour.

Resealing Windows and Doors

Another task worth paying for on the same day of a window sill replacement would be to have your windows and doors resealed or at least one window (i.e. the one with the window sill replacement).

Since this work tends to take between 30 minutes and two hours, a professional should be able to replace your window seal and perform resealing work on the same day. That is unless you wanted extensive resealing of many windows and doors.

The cost of resealing windows/doors:

  • Reseal window unit 61cm 101cm: £25 to £50
  • Reseal window unit 119cm x 101cm: £35 to £60
  • Reseal window unit 177cm x 116cm: £55 to £80
  • uPVC door seal replacement for standard sized door: £45 to £70

Labour Costs and Timescales

The price of labour is what you pay the tradesperson for their time and work. It is added to the cost of supplies for your total bill if paying a professional to replace a window sill for you.

installing window sill

As for the actual price figures, a window sill installer could charge about £15 to £25 per hour. With it generally taking between 1.5 hours and 3 hours for a contractor to replace a window sill, the total labour cost is likely to land between £30 and £75.

The reason for the £30 figure is that even with 90 minutes of work, you’re likely to be charged for two hours of labour, hence £15 x 2. Again, this is an average.

A particularly large window sill or one that is complex to install for other reasons such as accessibility issues could even take four hours or more to install. It is unlikely that the job will take less than an hour, however.

The cost of labour could also be impacted by the size and type of window sill replacement as well as ease of access. In addition, where you live will also play a role in shaping your final bill.

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Cost Factors of Installing a Window Sill Replacement

As we’ve discussed, 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

First and foremost, the cost of replacing a window sill primarily depends on the type you opt for. This would mostly be down to the material used.

On the one hand, MDF window sills cost about £10 to £20 standalone, with the supply cost of PVC window sills generally being between £15 and £40.

On the other end of the price range, stone window sill replacements usually cost more than £100, with concrete window sills tend to be priced around £120 to £180.

However, in addition to the materials used, the design of the window sill, as well as the quality of the brand/product, could also impact the replacement window sill cost.

Size of Installation Area

Of course, 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. This could bring up the cost of labour, but in most cases, it won’t.

Location of Property

If you live in the southeast of England, you are probably looking at contractor prices (in general) that are above the national average. On the contrary, those living in the north of England, Scotland and Northern Ireland would probably pay less than in most parts of the UK. All in all, location matters when it comes to what labour prices you can expect.

With all that said, the difference is not likely to be huge, considering that the average labour cost of a window sill replacement is about £50 (assuming a two-hour job). That said, it’s still a cost factor that shouldn’t go overlooked.

Ease of Access

Last but not least, how accessible the window area is could also shape your total bill. The easier a professional can access the work area, the quicker the task will be. Ultimately, a faster job may mean a lower labour price.

What’s Involved in a Window Sill Replacement?

The steps needed to replace a window sill can vary depending on the method used. What’s required will also vary based on the type of window sill being installed.

installing window sill

However, in this section, we’ll be looking at a common method employed for this work for replacing an interior and wooden window sill. If replacing a window sill DIY, always follow the manufacturer’s instructions (more on undertaking this task DIY in the next section).

1. Preparation

Before any work can get underway, certain preparations are needed. If you decide against replacing the window sill by yourself, you’ll need to find the right professional for the job. Otherwise, you’ll have to source the materials and tools required (unless you already have them).

The following tools may be needed:

  • Utility Knife
  • Putty Knife
  • Pry Bal
  • Pliers
  • Measuring Tape
  • Pencil
  • Chisel
  • Mallet
  • Claw Hammer
  • Reciprocating Saw
  • Drill
  • Finishing Nails
  • Multitool
  • Suitable adhesive
  • Table saw

2. Removing the Old Window Sill

Firstly, the window must be opened before a utility knife can be used to hoist up the existing window sill. You’ll need to cut through the various layers of paint, caulk and glue so that you loosen up the sill trims. A putty knife may be used to loosen the window sill further. Using a blade of a multitool would also suffice.

Use your reciprocating saw to cut a vertical line through the sill. You could use a power tool, but you should only do so if you are well versed in its use. Again, always proceed with caution whichever routes you take when replacing a window sill.

One approach to removing the window sill could be to cut two lines (a vertical line and a diagonal one) so that you cut out small pieces at a time. Ensure you don’t cut into the outer sill. It’s important that you do not come into contact with the nails between the interior and exterior sill.

A simpler alternative to the work described in the above paragraph would be to employ a small saw, putty knife, chisel and pry bar. These can be used to simply pry up your window sill.

Some window sills will be more difficult to pry up than others, so make sure not to rush the job even if it’s taking a bit longer than you anticipated. The jambs will probably be nailed at the bottom. When you come across them, use the diagonal pliers to remove the nails.

3. Fitting a New Window Sill

If needed, cut the window sill material to size. That said, you could have this done in a relevant store, or you could purchase a window sill to the exact dimensions needed.

Assuming you want to finish the window sill with suitable paint, the first part of actually fitting the new sill would involve pre-drilling holes to ensure the wood won’t split or suffer damage. Fix the skirting board in position. With a drill, add the finishing nails such that they are right below the wood surface.

Next, add an adhesive. This will strengthen the installation if needed. Finally, add a finish to the nail heads such that they match the sill as a whole. For adding a stain or paint to the window sill, always follow the manufacturer’s instructions.

Adding 2-3 coats of a clear finish can make a window longer lasting and less prone to damage. Make sure to give it sufficient time to dry.

Can I Install a Window Sill Replacement Myself?

The good news is that replacing a window sill is suitable for a DIY enthusiast. Once you have the right skills and knowledge and understand the necessary safety steps, it’s fine to do it yourself. Again, always follow the instructions provided by the manufacturer for practical and safety reasons.

fitting window sill

Hazards/dangers to consider when replacing a window sill:

  • Carrying loads.
  • Use of tools that could cause injury without proper care taken.
  • Incorrect installation (particularly if not following instructions fully).

Building Regulations & Planning Permission for a Window Sill Replacement

As for the rules relating to window sill replacements, there are some building regulations to follow, but planning permission will never be required. That is, unless you intend to undertake additional work along with replacing a window sill, then it may apply.

The following building regulations apply for replacing a window sill:

  • The bottom of the openable area should be no greater than 110cm above the floor space.
  • Window sill products must comply with the law and regulations*.

*This should be guaranteed so long as the window sill is sourced from a reliable provider. Only have a window sill installed that is acquired from a reliable provider.

If in any doubt regarding building regulations, contact your local council. More information on building regulations and planning permission, in general, can be found on the Planning Portal.

The rules may differ depending on where you live in the UK. Building regulations approval and planning permission can come with fees of around £100 to £200.

Where planning approval is required for a project (e.g., planning permission is often needed for building an extension), it can take up to eight weeks for an application to gain approval. However, it is usually faster than this.

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 & cons and remind you of their average supply prices.

PVC Window Sills Cost

These window sills are a popular choice and come in a wide range of sizes, finishes and colours. This includes PVC window sills that are designed to replicate other more expensive materials like stone.

PVC window

Among the core advantages of the window, sills are their low-cost (£15 to £40 on average), moisture- and sunlight resistance, durability and their ability to protect against heat and water.

One concern is that with cheap PVC materials, there is a risk of the presence of formaldehyde which can be harmful to your health. For that reason and more, it’s best not to simply go with the cheapest option you find.

That is unless it also happens to offer the qualities desired, but this is less likely to be the case unless, for instance, the product is on sale. They will also come with a lower load limit than many other stronger choices.

Stone Window Sills Cost

While costly with an estimated supply price of about £90 to £120, natural stone offers a beautiful aesthetic, the most longevity out of any of the choices discussed here, and a wide range of colours/styles to choose from, and they can add value to your property.

In fact, expanding on that last point, natural stone window sills could, for all you know, be the difference between selling a home and not. It might be that extra benefit needed to push prospective buyers over the line and to make the offer.

Some issue worth noting with stone window sills is that cracks and scratches can appear over the years. They are also unsuitable for prolonged water exposure. It’s also important to ensure paint and acidic liquids do not spill onto a stone windowsill, particularly if it’s made of marble.

Wood Window Sills Cost

Timber window sills are fairly commonplace and have been in use for generations. Solid wood window sills are long-lasting, easy to access, and have the potential to add a bit of insulation to your home. Some choose to simply fit wooden window sills as they are, whereas other homeowners prefer to have them painted.

wood windowsill

The average cost of wood window sills is £20 to £60. This is the standalone cost as opposed to the total wooden window sill replacement cost.

As for the downsides, like any timber home fittings, wooden window sills are prone to wood rot. To ensure protection against rot and mould, a timber window sill requires maintenance on an ongoing basis.

For a similar option to an ordinary timber window sill replacement but with better protection against the damp and humidity, consider particleboard, which is a type of engineered wood.

MDF window sills are in the same category as particleboard window sills, with MDF standing for medium-density fibreboards. MDF window sills have a supply cost of about £10 to £20 and are therefore actually cheaper than regular timber products.

Hiring Contractors for a Window Sill Replacement Checklist

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.

Checklist of hiring a window sill replacement contractor:

  • Ask friends and family for recommendations.
  • Obtain several quotes.
  • Have a look at any online reviews/ratings different contractors have
  • Ask about their previous work.


What is a window sill?

Put simply, it is a horizontal surface installed at the bottom of a window to offer structural support and secure the window in position. Window sills are often used to lay down items like plants.

How do you replace an exterior window sill?

The process is similar to replacing an interior window sill. After cutting out the old window sill, the new one is installed but unlikely with an indoor window sill.

It should be primed, undercoated and painted (ideally to match the window as a whole). External window sills need more protection since they face the elements directly, unlike indoor window sills.

How long should curtains hang below a window sill?

Preferably, the curtain should hang to within half an inch of the floor.

How do I know if I need to just replace a window sill or both the window sill and the window itself?

This would depend on the extent of the damage. If in doubt, consult a professional.

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 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.

Would a rotten window sill replacement cost more than replacing a less worn window sill?

It may cost more, but it would depend on factors such as whether or not other elements of the window space (even the window frame itself) needs to also be replaced or if it proves particularly difficult to remove.

Does an interior window sill replacement cost less than an external window sill replacement?

Generally, yes, since an exterior window sill replacement usually involves more treatments being added to the freshly installed sill to protect against the elements.