How to properly frame/finish "trimless" interior doors?

Question

I decided to try a couple of "trimless" interior doors in my add-on room, like this pic. No trim, no cut, line etc. Just smooth drywall up to the actual door opening.

It turned out pretty well, but the problem is that I'm not sure the proper way to do it. I just ripped the trim off some cheap standard interior pre-hung doors, installed the frames in the rough openings, and butted the drywall up to it, filling in with mud as needed to achieve the smooth edge.

The problem is, obviously, that some of them are cracking where the mud is very thin on the wood door frame, and doesn't stick to the wood very well. When the door gets slammed or slightly flexes the frame due to use, it creates cracks.

Can anyone enlighten me to the correct way to achieve this effect to prevent it from cracking?

Thanks!

Answer 1

If you look at the documentation for a commercial "trimless" door jamb kit you'll see that there's an integrated flange that creates a positive connection between the jamb and the wall. This mostly eliminates the kind of impact movement you've experienced.

The flange also acts as a taping bead, avoiding the interaction of joint compound and wood, which usually isn't a good combination.

You could probably retrofit a metal strip to serve the same purpose. Pre-formed steel found at a building supply store might work well to overlap and partially wrap the jamb. You could probably have a siding shop bend you some metal that perfectly fits your jambs. You'd then need to cut out for the hinge mortises.

Or, if your jambs are very securely fastened to the framing, and the framing is solid, try taping the joint properly with paper or fiberglass mesh. No joint should ever be finished with joint compound alone.

Answer 2

I use tear-away or j-bead, like this: Trim-Tex, with regular pre-hung doors - just omit trim. You'll want to sand and stain the wood prior to any drywall work, so the grain is somewhat sealed up, before you start slinging mud.