5/4 jamb stock as backing for crown moulding

Klawman

Gary Katz mentions in a DVD using finger joint 5/4 jamb stock as a backer for crown moulding but says nothing more about how it is used. I understand you can make triangular blocks or rip studs to give them a triangular dimension, but 1x? What is he talking about?

I can see ripping a board. Say a 5/4x5 at 2" and nailing the 3" half to the ceiling and the 2" to the wall or whatever fits the size and spring angle. Is that what he is talking about?

Talking about backer board, does the material make much difference? Is pine to soft?

Thanks

Bob Mariani

A blocker is placed on the wall so give move nailing material for the crown. Nothing more than that. Pine works fine.

Klawman

But in what configuation would you typically use 5/4 jamb stock, which I understand is actually 1". Say ceilng joists are parallel to the wall and the drywall plate only extends 2" from the wall, and the inside meaurement of run along the ceiling is 3-3/4". Assuming I have a 5/4x4 piece of finger joint pine jamb stock. Rip it with the table saw's blade beveled so the cut parallels the spring angle. In cross section it is a trapezoid with a base of 3-1/2" and a top of perhaps 3-1/8" (as opposed to the triangular cross section one would end up with if the ripped a 2X4 or 2x6)? Then it is your choice if you also want to run a piece along the wall or simply shoot nails into studs?

I am nailing the 5 1/4 crown in this room with individual blocks, but plan on doing the rest of a 2400 sq ft house with continuous backers.