I have installed a new pre-hung door that needs to blend in with the surrounding wall. The door is a flat slab and will be painted the same as the wall. I don't want to use door trim as I need a flat look. How do I conceal the gap between the frame and the door jamb? I could use plaster but I think it will crack over time.
I'm going to take a stab at this one, though I've never tried this for something large like a door frame.
Go get some self-adhesive fiberglass drywall tape and cover the area to be blended. Mud the seam, sand and repeat until smooth and the surface is blended with the wall. Prime and paint to match.
Alternatively, you could try peeling the paper off some scrap drywall and gluing it to the wall, and then doing the same as above with drywall compound.
I think these will help prevent it from cracking. You'll want to make sure the door frame is well secured to minimize any "give" that would crack it.
Just for the sake of completeness, here is what I was thinking of doing until Steven came up with a better/easier solution (at least on paper):
I was planning on packing the gap with plaster (or more likely setting-type joint compound), and then scoring a stress relief gap around the perimeter of the door. Then filling up the gap with caulk. Sort of like on parking lots when you see caulk between concrete slabs. If done right I believe this to be quite acceptable visually.