Replacing a Sill and Threshold

An exterior threshold takes a lot of abuse from foot traffic and weather, and it must be in good shape to keep the weather out. It can be replaced with a wood or metal threshold, either of which is available with a rubber gasket for sealing out the cold.

There is usually a sill below an exterior threshold. If the threshold is rotted, the sill probably is also. The sill is beveled on one side to drain water away from the house. Replace a sill using sill stock that has the same profile (shape) as the old sill. It fits tightly between wall studs and under the jambs and casing, so it has to be cut before it can be removed.

You may want to replace an interior threshold because the old one is ugly or because new flooring on one side of the doorway calls for it. An interior threshold simply rests on the floor with no sill under it.

Prestart Checklist

Time
2 or 3 hours

Tools
Circular saw or reciprocating saw, saber saw, hammer, chisel, nail set, tape measure, square, drill

Skills
Basic carpentry skills

Prep
Protect the floor with a drop cloth.

Materials
New threshold and/or sill stock, flooring adhesive, galvanized finishing nails, caulk