PermaBase can be fastened with either a 1-1/2" galvanized roofing nail or 1-1/4" cement backer board type screws are used with wood framing. If you are attaching the PermaBase to 20 gauge or heavier metal framing, use 1-5/8" S-12 cement backer board screws. DO NOT use typical drywall screws.
On the walls and floor/countertops, attach fasteners 8" o.c. in each direction. On the ceilings it's 6" o.c. in each direction.
As you apply pieces of PermaBase next to one another, leave a gap of 1/8". You will pre-fill this gap with mortar during the taping process.
You will need tape the seams with a 2" wide alkali resistant mesh tape. Using your trowel, pre-fill the gaps between the boards and coat the area with your mortar. Place the mesh tape over the joint and remove excess material using your trowel.
You can use a typical drywall utility knife score and snap the PermaBase cement board. Turn board over and make a second pass of this cut. The edge will be clean and smooth.National Gypsum Company (click for more information)