Replacing a sill and threshold

Sill and threshold get worn out from weather after years, just like any other home furniture and accessories. Most of the time we won’t even notice them until it became very bad in condition. You can save quite a bit of money by replacing them yourself with metal or wood threshold, together with a rubber gasket as sealing.

Normally, there is a sill under an exterior threshold and it usually get rotten if the threshold is already rotten. In order to drain water away from the house, the sill is beveled on one side. Sill stock can be used to replace old sill with new sill in same shape. As the sill fits tightly between wall studs and under the casing and jambs, it usually has to be cut before it can be removed.

Even if your interior threshold might be still in good condition, you might want to get it replaced as well in order to match the new flooring on the side of the doorway. 

Checklist To Replace Sill and Threshold

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

Preparation
Protect the floor with a drop cloth.

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

Replacing a Sill and Threshold

A threshold is placed under the door or rests on top of a sill, forming an extends outward.

Alternatively, it can rest partially on the sill and a piece of blocking.

In newer homes design, a wide metal thresholds extends outward is used instead of a sill.

Replacing a threshold:

The threshold is fitted below the stops and against the jambs. In order to remove it, you may need to use a nail set and hammer to poke the nails through. Then, it can be tapped out using a block of wood and hammer.

Don’t throw away the old threshold yet, use it as template to measure and cut the new one.

Once it is cut out, try to fit it before slipping it into the position. Next, apply flooring adhesive to the floor, drill some testing holes and secure it with 10d casing nails. After that, cover up the nail holes with exterior wood putty.

Replacing a sill:

As the sill is nailed under the jambs, in order to remove it, you will have to cut it into pieces. You will need to cut out a big middle section before chisel or pry out the smaller sections on the sides.

If you are able to remove the old sill without damaging it, you can use it as template measurement for your new sill to ensure the length is accurate. Otherwise, just tap the new sill in and adjust accordingly.

Once it is fitted in, apply flooring adhesive and secure it with 12d casing nails.