A Comparison of Tile Backer Boards
Earlier this month, I got started with another shower tile renovation for one of my Denver tile contracting clients. In this particular case the shower tile was still intact, which is a rarity considering the tile was set on green board. I think one of the reasons it had still survived was it wasPosted — Updated
Permabase is National Gypsum's product and it is very much like WonderBoard from Custom Building Products. Both of these boards are a cement and aggregate core with a fiberglass mesh "skin". Durock from USG is a slightly lighter weight version of comparable construction methods.
The other main type is what I call the "Hardie" type. As you may have guessed, HardieBacker is a non-aggregate based product from James Hardie. The same people who make a HardiePlank siding. Custom Building Products has their version of this, called Rhino board, but they limit it to ¼" thick and recommend it for floors and countertop installations.
Cost, strength, and weight will vary from product to product. In my area the cost of a 3 x 5 foot ½ inch thick sheet of any of these products runs about $11. The ¼" thick versions are usually about a dollar cheaper. Weights range from 2.4 pounds / sq ft to 3.0 pounds / sq ft for the ½" thick stock. That relates to 36 pounds for the lighter weight Durock and 45 pounds for the WonderBoard.
HardieBoard is in between at 2.6 pounds sq ft or 39 pounds for a 3 x 5 foot sheet. These numbers can mean a lot when you need to carry a dozen sheets up three flights of stairs (like a project I did a few months ago). Where the biggest differences lie however, are in the strength departments. The aggregate based products are lower in both flexural strength at about 750 to 900 (psi) and in compressive strength at about 2200 to 2500 (psi). The "Hardie" type is more than double in both areas 1700 psi flexural and 6500 psi compressive. To give you an idea of how tough that is, fiberglass skinned "drywall" like DensShield is only 450-600 psi compressive.
For normal shower installs, I prefer the HardieBoard hands down. The primary reason has to do with the ease of cutting and lack of the "crumbly" aggregate. HardieBoard's "grain" is very fine and does not release the fine gravel like particles the other aggregate type products do. You can score this for cuts, but I use a thin diamond dry cutting blade in my grinder. It makes more dust this way, but it is fast and leaves a very clean edge. (Breathing this dust is bad, so cut outdoors and use a dust mask.) The lack of aggregate in the "Hardie" types reduces the chance of gouging a new acrylic or shinny new enameled tub.