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Home Improvement

2001-09-01 11:07:00

Replacing thresholds

Question: The threshold at our front door is rotting out. It is nearly 40years old. How much of a job is it to replace? How do I remove the old without damaging the door casing?

Answer:  The first step would be to be absolutely certain that the sides of the door frame are not also rotten.  Many times the rot starts at the junction of the threshold(or door sill) and the upright portion of the door frame.  If this is the case it may be easier and produce a better end result if you replace the entire door frame.If the uprights are solid and the sill is rotten you must first detach the sill from the uprights.  Before the door was installed, the sill was nailed to the uprights from the bottom,  Using a hack saw, cut horizontally through the joint between the sill and each upright.  Once this is done it should be easy to knock the sill out from the interior side.  Sawing through the sill somewhere near the middle may make this job easier.The new sill can now be put in place of the old one and since you can't nail from the bottom like the original, you'll have to nail or screw the new sill to the floor.  Be sure to caulk all the joints and seams and paint all exposed surfaces to protect all wood parts from water.  In fact, if the new sill has not already been primed, you might want to prime all four sides and especially both ends before installing it.If the old sill is thicker than the new one, you have the option of making a new one out of thicker material or shimming under the ready made one.  Be sure to use cedar or plastic shims so they don't deteriorate. If more thickness is needed use a solid piece of wood milled to the exact thickness needed.  I don't recommend plywood because of the possibility of delamination.