I have mentioned what damage water can do to building materials. Using appropriate building materials (i.e. water resistant materials) is critical when it comes to durability. And despite the word on the street, or the marketing material, or what your contractor may tell you, the famous ‘green board’ has no place in the wet areas of your bathroom.
Think of wet areas as everything that is tiled. Green board is still a gypsum core with paper backing on both sides. And paper and water don’t mix. The board eventually could get compromised and grow mold, leading subsequently to indoor air quality (IAQ) issues.
I would recommend paying a few bucks extra and investing in cement board, which definitely is water resistant. How do I know? Well, the experts say so, and there is anecdotal evidence.
I have a little piece that has been sitting for a number of years in the garden, and it is still holding up just fine. Try that with a piece of green board!
Cement board was again our choice for the bathroom wet areas. In our case that was the shower stall, the area behind the toilet, and around that lavatory.
The shower stall will receive cement board almost reaching up to the ceiling. In the area surrounding the toilet and lavatory we limited the cement board to four feet above the floor. This way all wall areas that would intentionally or could accidentally receive water have a paper free, cement based and water resistant wall board. I also highly recommend to use special, alkaline resistant screws to attach the cement board to the framing.
The cement board will receive additional waterproofing and tiles, which should give us the reasonable amount of durability we are seeking.
More about the waterproofing and tiles in the coming posts.