backerboard question

Wasted effort to do seams on a countertop. IMO, YMMV.

I think it is different, because I was yelled at once for grabbing the wrong stuff. Something about i had to suitable for the pH?

Tom @

Yes, it is different. The backerboard stuff won't deteriorate with the thinset. They usually have it close to the backerboad in the tile section at HD/Lowes.

Huh? One is fiberglass and the other is ... fiberglass?

Sounds like the way they put the same cleaners into jugs that say "driveway cleaner", "deck cleaner", etc.

I guess the difference might be in the coating that's applied to the fiberglass. Dry wall joint compound sets by drying. "Thin set" likely dries by hydration of portland cement or by reaction with something in the air (CO2 or H2O).

It's not exactly a major cost item so why take the chance of getting it wrong.

Because I don't have your sheepish mindset. Ultimately the costs come down to what you know and how you apply that knowledge.

My guess would be, it's more likely to be a merchant manipulation than a genuine difference.

Marketing people are taught these days to label things with a focused application, not a description of the contents, because it divides the market and improves retail profits. This is why there are 1000 different spray cleaning products made from a grand total of about 5 ingredients, instead of 5 barrels of ingredients and a recipes handout.

OK, follow my sheeping reasoning. Hardibacker calls it out specifically, Thinset manuf call it out specifically and cement board manuf. call it out. They sure are herding us sheep. But I suggest you stray from the flock and carve your own path to show those marketing folks.

Huh. They specifically say, "don't use fiberglass tape labeled for gypsum board?"