Drywall layout for odd ceiling height

I'm remodeling a bathroom in a 1926 house and will be doing a plaster veneer. Blue board seems to be the recommended substrate. It's available here in 4x8 sheets.


The walls are 100 inches tall, which means two sheets butted side by side leaves a gap of 4 inches. Two walls are also 8 feet 3 inches long, again leaving a gap of 3 inches.

For the horizontal gap, I can buy more sheets and create a single seam in the wall, although it creates quite a bit of waste. What do I for the height problem? The baseboard will be 3.25 inches high so I can't cover up the gap at the bottom.

How should the drywall for the walls be laid out?

 

Drywall is available in 54" wide sheets - blueboard is not?

 

Where are you buying your blueboard? I'm not overly familiar with blueboard but I know it also comes in 12' sheets, not sure about 54" wide. Check with your local drywall supply house, they'll have a better selection than a big box store. I don't think the number of joints are as critical when applying plaster veneer as it will hide a lot - but the plasterer might disagree with me

 

And why in the world are you going over it with plaster?
It's just not needed, last thing I'd want in a wet, earthquake prone area.

 

Blueboard is not available in 54 inch wide sheets at my drywall supplier in a major metro area.

I'm doing plaster veneer because I want the look to match the rest of the house and it provides a harder finished surface than drywall. The rest of the house was plastered in 1926 and has what is called an "old world" finish.