Window Sills

Q: What is the best material for internal window sills?

MDF window sills are one of the most popular choices for internal use due to their smooth finish, cost-effectiveness, and resistance to warping. At MR Mouldings, we manufacture moisture-resistant MDF sills that are perfect for painting and suitable for most interior spaces. We also offer hardwood and softwood options for a more natural wood look.

Q: Can I paint your MDF window sills?

Yes, all our MDF window boards are supplied unfinished and ready to paint. The smooth surface takes paint exceptionally well, allowing you to match your window sills to your room décor or trim. For best results, we recommend applying a primer before your final coat.

Q: What edge profiles do your window sills come in?

Our collection includes popular profiles such as bullnose and chamfered window sills, offering different levels of detail to suit both modern and traditional interiors. If you need something specific, we can also manufacture custom edge profiles on request.

Q: Are your window sills suitable for bay or curved windows?

Yes, we stock a range of flexible window sills and mouldings that are ideal for curved or bay window installations. These are crafted from bendable wood materials that retain the look of standard mouldings while offering added flexibility for non-standard spaces.

Looking for high-quality window sills that finish your interiors in style? At MR Mouldings, we offer a wide range of MDF window sills, available in various profiles, lengths and finishes to suit both modern and traditional spaces. From bullnose to chamfered edges, our window boards are designed for durability, smooth finishing and easy installation.

Take a look at our full collection of paint-ready MDF window sills, or pair them with our matching Skirting Boards for a complete interior finish.

Shop now to upgrade your interiors with precision-crafted mouldings.

Made to order Moisture-resistant MDF Made in Britain

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Stepped Scallop Splayed Ogee Pencil Round Chamfered Bolection Ovolo

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Made to order

Pencil MDF Window Board

from £7.97£6.64 /length £3.62£3.02/m

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Fire Rated · Euroclass B

Made to order

Pencil Fire Rated MDF Window Board

from £42.00£35.00 /length £19.09£15.91/m

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Matches our skirtingCoordinated profile families

Moisture-resistant MDFWon't warp, twist or crack

Made in BritainMachined in our Epsom workshop since 2003

UK delivery in 5–7 working daysOr free collection from Epsom

Window Sills Overview

Why Choose Our Window Sills?

Our MDF window sills are precision-cut in-house using high-grade moisture-resistant materials. With a smooth, consistent surface, they’re ideal for painting and can be finished to match any décor. Whether you're working on a renovation or a new build, our window sills combine style, practicality and long-lasting performance.

Manufactured from high-density, moisture-resistant MDF

Smooth finish for easy painting and decorating

Crisp profiles like bullnose and chamfered edges

Available in a range of depths and lengths

Trusted by tradespeople and DIY enthusiasts across the UK

MDF Window Sills – Built for Modern Interiors

MDF window boards offer the perfect balance between affordability and durability. Unlike natural timber, MDF is less prone to warping or splitting, making it ideal for interiors where clean lines and consistent finishes matter most.

These internal window sills are popular in contemporary homes, rental properties and commercial spaces thanks to their:

Cost-effective pricing

Lightweight, easy-to-install design

Compatibility with matching skirting and architrave sets

Custom & Flexible Options Available

Got an awkward space? No problem. We also offer:

Flexible window sills for curved or non-standard window bays

Bespoke sizing on request

Hardwood and softwood options for customers wanting natural timber aesthetics

Browse our Flexible MDF Mouldings or get in touch for custom requirements.

Finishing & Installation Made Easy

Whether you're refreshing a living room or completing a large fit-out, our window sills are designed with ease of installation in mind. Each board comes ready to paint and can be trimmed on-site for a snug, professional finish.

Easy to cut, shape and fix

Ideal for use alongside our Architrave and Skirting Board collections

Works in both modern and traditional interiors

Window Sills FAQ

The common questions, answered — so you order the right profile first time.

What is the best material for internal window sills?

MDF window sills are one of the most popular choices for internal use due to their smooth finish, cost-effectiveness, and resistance to warping. At MR Mouldings, we manufacture moisture-resistant MDF sills that are perfect for painting and suitable for most interior spaces. We also offer hardwood and softwood options for a more natural wood look.

Can I paint your MDF window sills?

Yes, all our MDF window boards are supplied unfinished and ready to paint. The smooth surface takes paint exceptionally well, allowing you to match your window sills to your room décor or trim. For best results, we recommend applying a primer before your final coat.

Do you offer custom window sill sizes?

We understand that not all windows are standard size. We offer bespoke MDF window sills made to your exact measurements. Just get in touch with our team to request a quote for your custom window board requirements.

What edge profiles do your window sills come in?

Our collection includes popular profiles such as bullnose and chamfered window sills, offering different levels of detail to suit both modern and traditional interiors. If you need something specific, we can also manufacture custom edge profiles on request.

Are your window sills suitable for bay or curved windows?

Yes, we stock a range of flexible window sills and mouldings that are ideal for curved or bay window installations. These are crafted from bendable wood materials that retain the look of standard mouldings while offering added flexibility for non-standard spaces.