Check the frame before shopping for the slab

Look beyond the paint. Check the hinge recesses for split wood, test for movement at the hinges and inspect the bottom of the jamb for damage. Close the old door and record uneven gaps. If it never fitted well, copying every measurement from it can reproduce the problem. Measure the frame itself at several positions.

JELD-WEN's interior slab guide calls for inspecting the existing jamb before installation and checking fit before hardware preparation JELD-WEN: Interior Door Slabs (JII110).

A slab replacement is attractive when good casing or plaster would be expensive to disturb. It is less attractive when the jamb needs extensive repair anyway. Ask the carpenter to price the completed fit, including machining and finishing, alongside a prehung door and trim repair. The cheaper boxed product is not always the cheaper finished opening.

Record more than width and height

The slab replacement measurement sheet

  • Actual slab

    Width at several heights, height on both edges, and thickness.

  • Hinges

    Size, corner shape, recess depth and position from one consistent reference edge.

  • Latch preparation

    Bore size, centre height, edge preparation and backset.

  • Closing edge

    Bevel, handing and relationship to the existing stop.

Backset is the distance from the door edge to the centre of the handle bore. Hinge mortises are the shallow recesses that let the leaves sit flush. Both are easy to overlook when a catalogue lists a door simply as a width and height. Photograph the closed door from both sides and mark the hinge side so handing is not guessed from a phone conversation.

A factory-bored slab may be inconvenient if its latch height differs from your existing strike. An unprepared slab allows custom fitting but adds machining work. Likewise, nominally matching hinges may have different corner radii or leaf thickness. Confirm the template before cutting; filling an unnecessary recess is a poor way to begin.

Check the new door against the finished floor

Include the flooring you will actually keep, plus any planned underlay, rug or threshold. Test the swing across the floor, not only the closed position. Check the product's permitted trimming before choosing a tall slab with the intention of cutting it down. Hollow-core trimming limits depend on the model and what has already been removed.

If switching to solid core, confirm hinge and frame fastening capacity. A slab-only price should include any necessary hardware changes. Arrange safe handling before the old door comes off, especially upstairs or in a tight hall.

What a successful slab swap should do

The new door should swing without rubbing, latch with a normal push and release without lifting. The stops should meet it consistently without forcing it into a twist. Finish all newly machined areas according to the product instructions. If this is an exterior, fire-rated or other special assembly, do not apply an ordinary interior-slab checklist as approval to mix components; obtain the relevant system requirements first.