Setting Door Jambs Without the Doors
Thoughts on getting door jambs accurately set before the doors themselves are even built. August 27, 2009
Question
I'm working on a house that is doing kerfed door jambs - no casing. The sheetrock bullnoses into the saw kerf on the edge of the door jamb. The homeowner is in a huge hurry and wants me to install the jambs without the doors so the sheetrockers can get started. The framing isn’t all that good and I'm having to fix all the doorways. I'm very leery of hanging jambs without doors, and can foresee lots of potential problems such as racking, twists, and etc. We made a spreader block to slide down the jamb to check for twist and spacing, and have a thin spreader stapled to the bottom of the jambs, and theoretically, square is square right? The good news is that the jambs are 1 3/4 thick and laminated, so they are pretty stable. Anyway, if anyone has any tricks or tips that has done this before.
Forum Responses
(Architectural Woodworking Forum)
From contributor F:
Make a temp door or a full size sheet of plywood to get your reveals correct. We prefer a temp door.
From contributor M:
I used to install a lot of doors in the very fashion you are talking about when I did field work. I found that if the trimmer was up tight to the jamb and shimmed mostly between the king and the trimmer it was a lot more solid. We used only struct one material for the trimmers looking for the straightest material possible. Our jambs were only 3/4" thick though so you have an advantage with heavier stock. All the framing needs to be secure and using a lot of toe nailing and clips to re-enforce as needed. The reason for solid framing is after the doors where installed if the jamb was floppy, a good slam of the door would crack the drywall mud. I just used a good level, plumbed hinge side trimmer then hinge side jamb once again tight to the trimmer, and brought the strike side over till it was parallel.
Now the tricky part - we always hung the doors after the fact in the field to allow us to scribe to each opening. The jambs and walls will move from the time they are installed and the sheet rocker is done, not to mention all the moisture that has been introduced with taping and paint. My crew got pretty good and fast at scribing the doors and tight margins are easily achieved.
I do have customers these days that have us pre-hang and they will set prefinished doors then remove them and store them till later with mixed results. In your case with not having the doors you don't mention whether these are pre-hung or not, or if you have the capacity to field hang these. I would expect some issues if the contractor just wants you to set the jamb square and a pre-hung door will just fall right in.
From contributor A:
We had a huge job with 1 3/4" MDF doors that were taking out after hanging and sprayed with a very high sheen spray. We would countersink a #10 x 3" construction screw behind the hinge plates after we got the door hung properly. This will help to ensure the hinge locations stay put after repeatedly taking the doors on and off. We now do it on every top hinge on every door. I know some people throw a bigger screw in one of the hinges holes, but the screw never matches. Definitely use a temp door to check the openings.
From contributor E:
Contributor A’s correct. Get a temp door already prepped and use that, setting jambs so the doors fit properly. By the way, if the door is solid core and very heavy you can often just cutout a big hole in the middle of the door to cut down on the weight (making sure to not distort the door) to make setting easier.
From the original questioner:
I guess I have to make a sample door for every size door in the house. Oh yeah, and they're eight foot doors. I guess ya'll are pointing me down a road that I'd hoped to avoid, but ultimately had a feeling I'd have to travel. Thanks so far. I'll let you know how it goes. All the doors are totally custom built in our shop, and we'd have loved to do them pre-hung, but we're actually going to route the hinges in place as well, so all of that put together gives us a little flexibility, except that the jambs are locked into place by the sheet rock and a thick coat of plaster.
From Gary Katz, forum technical advisor:
We hang hundreds of them that way every year. The other guys are definitely right - use a temp door to set the jambs. We use a hollow core with the middle out at the top and bottom, which leaves a kind of lock rail in the center, which is the same way we set metal jambs in commercial. We secure a short level to the lockrail, so it's easy to set the jambs level with the template door. Make sure the trimmers/jacks are dead on and shimmed tight to the jambs. Check crossleg very carefully, though sometimes the walls will get jogged by the drywallers when they stock the sheetrock. If you don't know how to scribe your doors, you'll soon learn how. That's a good thing. Using pre-hungs is not the most efficient method, especially for eight foot doors.
From the original questioner:
Will do. I'm sure I'm being more paranoid than is really necessary, but definitely caring, and being cautious will save me some frustration later. Thanks for the help. I will report on our progress later.
From contributor W:
One more thing to consider - the weight of the door. We had this problem in the past where once the finished door was installed the weight of the door was much heavier than the template that we used and our reveal on the top at the lock side increased by an unacceptable amount. Why can't you just hang the jamb with the door on it and then remove and store the doors?
From contributor S:
Why don't you just hang the doors like normal and let them remove them or you remove them? Make sure they are marked correctly as to where they go and leave it at that. If you are worried the boarders will knock them out of whack then maybe put a spacer at the bottom so it can't open up. Screw them into place don't nail them or they might knock them out of square.
From the original questioner:
That's the kicker isn't it? We haven't built the doors yet, and they don't want to wait for them. They want the jambs hung so they can get going on the sheetrock.
From Gary Katz, forum technical advisor:
It's a good excuse to buy a nice plane! If you set the jambs with the heads dead level and the legs square/plumb to the head, the amount of planning will be minimal. In fact, if you haven't built the doors yet, we often set our jambs to net sizes (exactly 2/8 or 2/6 or 3/0), and then we buy our doors 3/16" under net size - they even ship them beveled on both stiles. That way, all you have to do is butt the door and the jamb and swing the door.
Most of the time, the amount of scribing/planing is minimal, even on an eight-foot door. And if the jambs are set tight to the template, and shimmed solidly, then the opening is never too big. If anything, it might be a tad too small. You can always take wood off the door but it's tough to add it. Honest, it's a cake walk.
The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor T:
All of the above is good advice. Normally, I flat refuse to set a wood jamb without a disclaimer since so much can happen to it and then I have to reset it for free. That said, I have set a ton of commercial grade steel jambs prior to hanging the slab. Just make sure your hinge jamb is plumb and straight, then cut three pieces of 1 x 4 the exact size you want the opening (usually the same as the header), cut a "v" groove in both ends, and then use this as a spacer to shim the strike jamb. First be sure to strike a line on the floor so the jambs line up. Works every time as long as you carefully plumb both jambs the same so the door isn't cocked when you install it. Biggest problem is that buildings move and things get clobbered prior to you setting the door and getting out of there.
