Homasote joints

Butt them together

We butted them together and then filled any voids with SpeedFinish patching compound.  Then the patch was lightly sanded cleaned and the whole surface painted.

What GRJ said is what I did also.

I used a regular Spackling Compund ,  but think  GRJ  has a better solution!!

GRJ and Fredstrains - did you have any issues with the homasote swelling or pulling moisture out of your joint/patching compounds since they contain water? I assume not since you did not mention it, but I just wanted to confirm.

Thanks to Tom's expert guidance, I used the right materials to do the fill, and there wasn't a hint of swelling.  Nothing like having an expert advising on materials.

Thanks Tom and GRJ. SpeedFinish it is then.

95% of the thanks goes to Tom, I just used the stuff he brought.

Sort of tangent question here to GRJ....did you use 1/4 plywood to make your curved rim as a finished edge?

Nope, it was 1/8" Lauan plywood, very flexible.  The first layer of the fascia was 3/8" 3-ply "wiggle wood" as Tom calls it, also very pliable.

@S Rice posted:

About to add homasote on top of my plywood and was curious if most people simply butt the pieces against each other, or if you leave a narrow gap for expansion and fill it with caulk?

Thanks in advance for your feedback.

I had NO problem with the Homosote Swelling with Spackling!

3/8" Lauan can be formed as tight as a 3"  radius as shown at the 3 1/2" step down at the coal yard.

The bendable Lauan is actually two plys of wood and a thick center  "ply" of very flexible adhesive.  If you use an atomizer and slightly dampen both surfaces the wood will keep bending tighter.  After bending it to the desired curvature let it dry in that configuration over night b/4 gluing.

The 4 X 8 sheets are made to bend either in the width or in the length.  Commonly classed as for barrel use or column use.  I use the barrel type.