What is an interior door threshold (stofdorpel)?
An interior door threshold is a narrow, slightly raised strip fitted between the jambs of an internal door, finishing the junction between the floor coverings of two rooms. In the Netherlands it is called a stofdorpel (literally “dust sill”) and is a common feature of internal doors in Dutch homes. It covers the joint between two floors and cuts down draughts and light under the door.
Beech is the usual material because it is hard-wearing and easy to saw and finish. In bathrooms and toilets natural or engineered stone is normally used. Dutch DIY stores sell beech thresholds about 22 to 23 mm thick and roughly 95 cm long, in depths from around 7 to 14 cm, which you cut to length yourself.
Recognising it
Turn one over and the underside is almost always hollowed out. This recess, known in Dutch as a cloister rebate, means the threshold only bears on its edges, so it sits steady on an uneven floor and does not rock underfoot.
Application
- Measure between the jambs. Measure at two heights at the bottom of the frame; old frames are rarely square. Cut slightly long and plane to fit.
- Seal before fitting. Prime or varnish the timber on all faces, including the underside, so it does not take up moisture on one side and warp.
- Fix it firmly. Screw it down with pilot holes or bed it in construction adhesive. A loose threshold tips when stepped on.
- Check door clearance. After new flooring or a taller threshold, the door often needs trimming. Check before gluing.
- Plan for accessibility. For wheelchair or walker users, leave the threshold out or set it flush with the floor, and stop draughts with an automatic drop seal in the door.
Common mistake: fitting a timber threshold in a bathroom. Wet mopping soaks the wood, it moves and the finish lifts. Use stone or engineered stone in wet rooms.
Related terms
- Threshold
- Door sill
- Cloister rebate
- Cast stone
- Bluestone
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