Green Building Q&A: Extension jambs for in-swing doors on double wall construction?
Martin, the depth of a door sill is waterproofed below the sill, with the showing part mainly being a durable layer to tread on so to speak. I have used both ice and water shield and leftover scraps of EPDM roofing. and some ot the retail product sold for sill flashing and detailing. Many ways to keep the water out if built with such. Janet, Thermotru doors are jambed by a shop along the way to the retail supplier. What they make a good carpenter also can make as that is how they will do it at their shop too. You may not get a Chlupp level of E conservation but you should get a door that fits the rough opening. Except for half round jamb extensions we mostly fabricate extensions onsite exactly to what ends up being the whatever odd dimension of all the built up materials. Both ways will get the job done, sometimes factory jambs are modified just a bit onsite.