How to Retrofit Weatherstripping on Arched Doors

You can use traditional metal V-fold weatherstripping, or the appropriate router jig for modern synthetic weatherstripping. May 12, 2008

I'm looking for advice on retrofitting a Tudor arched door with kerf style weatherstripping. The door is already in place. I'm pretty sure I can set up for the straight cuts with a circular saw and a guide on the wall, but cutting the kerf along the radius of the arch is perplexing me.

Forum Responses
(Architectural Woodworking Forum)
From contributor D:
The typical q-lon compressible foam requires the jamb to be rabbeted 5/16" further off the face of the door, then the 1/8 x 3/8" groove goes into the edge of that surface. This is very difficult to do on a curved head door frame unless done while it is being built. The historic solution was/is to use spring bronze, clipped across its width every 2" or so, so the metal forms leaves around the arched part of the door. The straights are done conventionally. This is a very good weatherstrip, but the new folks don't know about it and seem to only trust the spongy plastic stuff.

The q-lon and other types need to be rabbeted and grooved at manufacture. If the spring bronze won't fly, then you can pay $1200 for the special router jig that will put in a kerf at 45 degrees to the rabbet, and use one of several bulb type weather seals. Pemko has spring bronze, the router setup, and the bulbs.

From contributor G:
Pemko sells a trim router attachment that holds the router at a 45 degree angle allowing you to cut the groove you will need. We have done this many times. Page 120 of their catalog, part #640, replacement bits #640C. Seals that work best are S104, S105, S109. The q-lon type they sell is a little loose fitting in the groove and needs to be installed with silicone, making removal difficult.