White UPVC Capping Boards – 9mm, 2.5m & 5m Lengths
Sale priceFrom £9.99 Incl. Vat Regular price £12.00 Incl. VatUnit priceAnthracite Grey UPVC Capping Boards – 9mm, 2.5m & 5m Lengths
Regular priceFrom £19.99 Incl. VatUnit priceBlack UPVC Capping Boards – 9mm, 2.5m & 5m Lengths
Regular priceFrom £19.99 Incl. VatUnit priceLight Oak UPVC Capping Boards – 9mm 5m Lengths
Regular priceFrom £33.99 Incl. VatUnit priceRosewood 9mm uPVC Capping Boards (5m Lengths)
Regular priceFrom £33.99 Incl. VatUnit price240mm 3mm White Window Sill Cover Board Reveal Liner 2.5m
Regular priceFrom £32.40 Incl. VatUnit priceVery low stockWindow Cill With End Cap And Channel 1027mm x 225mm
Sale price £5.00 Incl. Vat Regular price £10.00 Incl. VatUnit price
Choose your profile
Which board do I need?
-
Most popular9mm Square Edge
- Clean flat finish, sits flush to the wall
- Most popular choice for modern windows
- Available 150mm to 600mm wide
- Multiple colours including woodgrain
Best for: Straight sills, contemporary interiors
-

3mm Slim Profile
- Ultra-thin overlay — minimal height addition
- L-shaped lip wraps the front edge neatly
- 240mm wide, 1.2m lengths
Best for: Tight-fitting sills, minimal build-up needed
Available finishes
Colours & Finishes
Colours vary by range and product. If you need help matching shades across boards, trims and accessories, get in touch and we'll help.
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White
-

Black Woodgrain
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Light Oak
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Rosewood
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Anthracite
Sizing guide
Board width & internal coverage
Use the guide below to choose the right board width for your window sills. Internal coverage accounts for a 4.5mm overlap on each side.
| Board width | Internal coverage | Good for |
|---|---|---|
| 150mm | ~141mm | Narrow sills, small windows |
| 175mm | ~166mm | Standard smaller windows |
| 200mm | ~141mm | Most common window size |
| 240mm | ~231mm | 3mm slim profile standard width |
| 250mm | ~241mm | Slightly wider sills |
| 300mm | ~291mm | Bay Windows, wider reveals |
| 400mm | ~391mm | Deep sills, conservatories |
| 600mm | ~591mm | Extra wide |
150mm
175mm
200mm
240mm
250mm
300mm
400mm
600mm
Frequently Asked Questions
How do I choose the right width for a window sill cover board?
How do I choose the right width for a window sill cover board?
Measure from the back wall to the front edge of your existing sill, then choose a board width that covers that depth properly. Many retailers sell uPVC window sill cover boards in multiple width options because the correct width is one of the main buying decisions in this category. If you are covering an existing front lip, make sure you account for the full depth and profile shape rather than measuring only the flat top surface. This is an inference from how these products are sold in multiple widths and from the way rounded profiles are described as covering the existing lip.
Are uPVC window sill cover boards suitable for bathrooms and kitchens?
Are uPVC window sill cover boards suitable for bathrooms and kitchens?
Yes. uPVC window sill cover boards are a practical choice for bathrooms, kitchens and other humid rooms because they are moisture resistant, easy to wipe clean and low maintenance. Unlike timber, they do not need painting and will not rot, swell or warp in the same way when exposed to everyday condensation and splashes. That is why they are commonly used where you want a cleaner, more durable finish around internal windows.
Are uPVC window sill boards better than timber?
Are uPVC window sill boards better than timber?
uPVC window sill boards are often the lower-maintenance choice because they do not need painting and are easy to wipe clean. They are also resistant to moisture, so they will not rot, swell or warp in the same way timber can over time. Timber can still suit some traditional interiors, but for a practical, easy-care finish, uPVC is usually the better option.
General questions
What are uPVC window sill cover boards?
What are uPVC window sill cover boards?
uPVC window sill cover boards, also known as window sill capping boards or window boards, fit over an existing internal sill to give it a clean, updated finish without removing the original underneath. They are a low-maintenance alternative to timber because they do not need painting and are resistant to moisture, staining and day-to-day wear. Square edge, bullnose and slim overlay options are available depending on the finish you want and the shape of the sill you are covering. This lines up with how specialist competitors describe the category and how they position uPVC as a practical cover-over solution.
Can you fit a uPVC window sill cover board over an existing sill?
Can you fit a uPVC window sill cover board over an existing sill?
Yes. Window sill cover boards are designed to fit over an existing internal sill, which is why they are often called capping boards. Most supplier guidance describes them as being fixed in place with a strong grab adhesive or no-nails style adhesive, making them a popular option when you want to cover a tired timber sill without a full replacement.
What is the difference between square edge and bullnose window sill boards?
What is the difference between square edge and bullnose window sill boards?
Square edge window sill boards have a flatter, sharper front profile for a cleaner, more modern finish. Bullnose, sometimes called hockey nose, has a rounded front edge and is commonly used where you want to wrap over and fully cover the existing sill lip for a neater finish. Competitor pages consistently describe bullnose as the profile that wraps around the front edge of the sill, while square edge is positioned as the cleaner-edged alternative.
Frequently Asked Questions
How do I choose the right width for a window sill cover board?
How do I choose the right width for a window sill cover board?
Measure from the back wall to the front edge of your existing sill, then choose a board width that covers that depth properly. Many retailers sell uPVC window sill cover boards in multiple width options because the correct width is one of the main buying decisions in this category. If you are covering an existing front lip, make sure you account for the full depth and profile shape rather than measuring only the flat top surface. This is an inference from how these products are sold in multiple widths and from the way rounded profiles are described as covering the existing lip.
Are uPVC window sill cover boards suitable for bathrooms and kitchens?
Are uPVC window sill cover boards suitable for bathrooms and kitchens?
Yes. uPVC window sill cover boards are a practical choice for bathrooms, kitchens and other humid rooms because they are moisture resistant, easy to wipe clean and low maintenance. Unlike timber, they do not need painting and will not rot, swell or warp in the same way when exposed to everyday condensation and splashes. That is why they are commonly used where you want a cleaner, more durable finish around internal windows.
Are uPVC window sill boards better than timber?
Are uPVC window sill boards better than timber?
uPVC window sill boards are often the lower-maintenance choice because they do not need painting and are easy to wipe clean. They are also resistant to moisture, so they will not rot, swell or warp in the same way timber can over time. Timber can still suit some traditional interiors, but for a practical, easy-care finish, uPVC is usually the better option.
What are uPVC window sill cover boards?
What are uPVC window sill cover boards?
uPVC window sill cover boards, also known as window sill capping boards or window boards, fit over an existing internal sill to give it a clean, updated finish without removing the original underneath. They are a low-maintenance alternative to timber because they do not need painting and are resistant to moisture, staining and day-to-day wear. Square edge, bullnose and slim overlay options are available depending on the finish you want and the shape of the sill you are covering. This lines up with how specialist competitors describe the category and how they position uPVC as a practical cover-over solution.
Can you fit a uPVC window sill cover board over an existing sill?
Can you fit a uPVC window sill cover board over an existing sill?
Yes. Window sill cover boards are designed to fit over an existing internal sill, which is why they are often called capping boards. Most supplier guidance describes them as being fixed in place with a strong grab adhesive or no-nails style adhesive, making them a popular option when you want to cover a tired timber sill without a full replacement.
What is the difference between square edge and bullnose window sill boards?
What is the difference between square edge and bullnose window sill boards?
Square edge window sill boards have a flatter, sharper front profile for a cleaner, more modern finish. Bullnose, sometimes called hockey nose, has a rounded front edge and is commonly used where you want to wrap over and fully cover the existing sill lip for a neater finish. Competitor pages consistently describe bullnose as the profile that wraps around the front edge of the sill, while square edge is positioned as the cleaner-edged alternative.
Need help choosing the right window sill boards?
Whether you are matching a style, checking sizes, or comparing options, we can help you choose the right product for your project.




