Big doorway, adding arches, need some advice...
 

In the new office I had to widen a doorway from 4' to 12' to get cars through. For a better look I want to add arches to the upper corners and then drywall. I've seen the prefab arches online, none at Lowes or Depot.

2 questions:

If I build them out of plywood what the best material to create the curve in between the plywood sheets?

And then whats the best method of drywalling the underside?

Cut many blocks from 2 x 4s the net width between your plywood shapes and rip some pieces for the vertical stud at each side and for the header. Nail the rips at the header and stud. Nail or screw the forms to the rips so that they are flush with the framing and fill in the arch with the blocks. It doesn't have to be solid, edge to edge. Install the drywall and trim to form.

Now, you can wet 2 pieces of 1/4 inch DW to follow the arch or just score the back of 1/2 DW strips every 3 inches or so and let it break on the backside as you form the arch. Lastly, install flexible DW bead of your choice, bullnose or corner. Commercial work asks for 5/8ths DW most of the time, but no one is gonna check your arch material.

Mud that puppy.

Milt already resonded, I was going to suggest ask him & Speedster, both really seem to know this stuff and who I would ask.. I just wish they were local...

Thanks Milt! I went your way and they came out really nice, taking pics along the way. Post when its all done!

Started off with a door sized cut out separating the rear bay door from the rest of the warehouse area:
http://forums.pelicanparts.com/uploa...1245964642.jpg
http://forums.pelicanparts.com/uploa...1245964857.jpg

Then:

http://forums.pelicanparts.com/uploa...1245965145.jpg

http://forums.pelicanparts.com/uploa...1245965206.jpg


http://forums.pelicanparts.com/uploa...1245965249.jpg


http://forums.pelicanparts.com/uploa...1245965297.jpg

http://forums.pelicanparts.com/uploa...1245965362.jpg
http://forums.pelicanparts.com/uploa...1245965419.jpg
http://forums.pelicanparts.com/uploa...1245965465.jpg

That's it. Dude, you're the man.