Oak Window Boards

Solid Oak Window Sills with a Bullnose Front Edge

A window board is the internal sill that caps the wall beneath a window, finishing the reveal where the plaster meets the window frame and giving you a solid shelf along the opening. Worked in solid oak, it does the same job as a painted MDF or plastic sill but reads as joinery rather than trim, carrying the same grain and colour as the oak doors and skirting around the room. Window board and window sill are the same thing - the two names are used interchangeably for the internal board - so whichever you call it, this is the piece that sits on top of the wall under the glass.

Every board is machined from kiln-dried prime grade oak with a rounded bullnose front edge and pre-sanded ready to finish, with no veneer anywhere in the build. Because it is solid oak throughout it takes the weight of plant pots, books or someone perching on the sill, and it can be sanded back and re-oiled in years to come rather than stripped and repainted. Choose the board by the depth that suits your wall and the thickness you want on show.

Choose the Depth and Thickness to Suit Your Wall

The depth is the front-to-back measurement and needs to cover the wall thickness plus a small overhang into the room, while the thickness is how chunky the board looks once it is fitted. Measure from the window frame to the face of the finished wall, add your overhang, and pick the nearest depth. All four options are solid oak with the same bullnose front edge:

• 25mm thick x 225mm deep: a slimmer board for shallower reveals.
• 25mm thick x 250mm deep: the same slim face with extra depth for thicker walls.
• 32mm thick x 225mm deep: a heavier board for a more substantial sill.
• 32mm thick x 250mm deep: the deepest, chunkiest option for wide reveals.

Match the Window Boards to the Rest of the Room

Oak at the window works best when it ties into the other joinery rather than standing alone. The same prime grade oak runs through our oak skirting boards at floor level and our oak architrave and oak door linings around the doorways, so specifying the window boards alongside them keeps the grain and colour consistent from the skirting up to the sill.

Finishing Your Oak Window Board

Boards arrive pre-sanded and unfinished so you can match them to the woodwork already in the room rather than being stuck with a factory colour. Seal the oak with a Treatex hardwax oil to protect it from spills and the sunlight coming through the glass, and it is easiest to apply the first coats before fitting so the ends and underside are covered too. A sill under a sunny window will lighten over time if left bare, so an oil or wax finish is worth doing rather than leaving it raw.

Why Oak Window Boards from UK Oak Doors

Because we make oak doors first, our window boards are cut from the same oak, so the sill under the window carries the same grain and tone as the doors and trim rather than a near-miss from a separate merchant. They sit within our wider oak skirting, architrave and accessories range, so doors, linings, architrave, skirting and window boards can all be specified together as one coordinated set.