Internal Frames

A door frame, or lining, is the timber surround the leaf is hung in. Getting it right matters more than most people expect: the frame sets the finished opening size, carries the hinges, and determines whether the door closes squarely for the next twenty years. Frames are sold to suit standard leaf sizes and common wall thicknesses.

Measuring and ordering

Measure the structural opening, not the old door, and check the wall thickness so the lining sits flush with the plaster on both faces. Order the frame in the same species and finish as the leaf so the reveal matches: see oak, white primed and walnut doors.

Finish the opening with door architraves and matching skirting. Fire rated openings need a certified frame with intumescent seals. External versions are in external frames, and side panels in internal side panels. Where two leaves are hung in one opening, a pair maker closes the meeting joint between them.

Frames, linings and what the difference means for you

A door frame is a rebated timber surround that the door closes against, and it is normally used where the wall is thin or where the door is exposed, such as a garage or an external opening. A lining is a plain, flat-sided timber surround with a separate stop planted on it, and it is what most UK internal doorways use because it can be made to match the wall thickness. Getting this wrong is the most common reason a new door does not fit an old opening. Door frames vs door linings sets out the difference with the measurements that matter.

Measure the wall, not just the door

A lining has to match the finished wall thickness, including plaster on both sides. If it is too narrow the architrave will not sit flat, and if it is too wide it will stand proud of the plaster. Take the measurement in three places, because older walls are rarely consistent. Our how to measure a door guide covers the sequence, and the door size guide lists the standard UK sizes.

Finishing the opening

Once the lining is in, the opening is finished with architraves around it and skirting running into it, ideally in the same finish as the door. Where two leaves meet in one opening you also need a pair maker, and where a narrow panel sits beside the door, an internal side panel. External openings use external frames and, where there is a sidelight, side panels for external doors.

Can I reuse the existing lining?

Often yes, if it is square, solid and the right depth. It is worth checking with a level in both directions before ordering the door, because a twisted lining will make even a perfect leaf bind.

Do fire doors need a special frame?

The frame or lining has to be sound and deep enough to hold the leaf and the seals. See fire doors and use fire rated hinges with intumescent strips and pads.

Is there a frame for a bi-fold opening?

Yes, but bi-fold frame kits are listed with the folding range rather than with the standard linings. They are stocked in white primed, unfinished oak, fully finished oak and walnut. See bi-fold doors.