When we build a shower, the substrate is where the project either holds up for twenty years or fails in three. Go Board is our default choice on shower walls for most residential projects. Here is why.
What Is Go Board?
Go Board is a rigid foam panel made by USG Durock. The foam core is expanded polystyrene, and the surface is a fiberglass-reinforced coating. The material itself does not absorb water. You do not need to apply a separate waterproofing membrane to it. It is fastened to studs just like cement board, seams and corners are treated, and then it is ready for tile.
What Is Cement Board?
Cement board (Durock, HardieBacker, and similar products) is a concrete-based panel reinforced with fiberglass mesh. It is moisture-resistant, not waterproof. Water that gets behind the tile will pass through cement board and reach the framing behind it. If that happens regularly, you have a mold and rot problem.
For cement board to work as a shower substrate, it needs a properly applied liquid waterproofing membrane over the top. That adds cost, time, and introduces the possibility of missed spots in the coverage.
Why We Default to Go Board on Shower Walls
Go Board is faster to install and waterproof by design. There is no waiting for a liquid membrane to dry or cure. There is no question about whether a corner got enough coverage. The panel itself handles the waterproofing, and we treat seams and inside corners with mesh and adhesive to create continuous coverage.
It is also lighter than cement board, which makes it easier to handle and position on walls.
The main knock on foam panels is compressive strength, but on walls where tile is bonded in adhesive and not taking direct impact, this is not a relevant concern for residential shower applications.
When We Use Cement Board
Cement board is appropriate for floors under tile flooring outside of wet areas, and in situations where it is already in place and in good condition. We also use Schluter Ditra uncoupling membrane over cement board floors to address the movement that causes tile and grout to crack over time in Florida's climate.
The Bottom Line
For shower walls, Go Board gets you to a waterproof, tile-ready surface faster and with fewer steps than cement board plus liquid membrane. Schluter KERDI is also a strong system and we use it on appropriate applications, but it requires more time and cost than Go Board for the same result on a standard residential shower.
We talk through substrate options on every project. If you have a specific situation or existing material you are working with, bring it up during the estimate visit.