Home>Discussions>INTERIORS>Molding & Carpentry>Anybody familiar with old cement board?
7 posts / 0 new
Last post
Anybody familiar with old cement board?

We just bought and I just started renovating an old (c. 1910) house that was completely renovated in 1974 or so. It's our third house of similar vintage, so I have had some practice.

The closets still have (mostly) original horsehair plaster on lath walls, but the rooms have been refinished in a product I've never seen before. From the stud side, it looks like approx. 5/16 inch gypsum wallboard with a paper backing, but then in the middle there's another 5/16 inch layer of what looks like cement, then a very smooth 1/8 inch finish layer. It's crazy heavy, as you would expect, and rock-hard. It's also in great shape as it has been covered with wallpaper for decades, possibly since it went up.

So is this 1974-vintage cement board? And a couple of follow-up questions:
It sanded and took plaster and paint very well in the first room I did, but I want to tile the bathroom and don't know if I should just scour and clean the surface or put up a backerboard. Cement backerboard on cement board sounds like overkill overkill?

And finally, when I stripped (about 4 layers) of wallpaper before painting the first room, the final layer was a navy blue/black-and-tan vertical stripe on paper so thin I can't imagine it was hung after it left the factory. I don't know if this was for easier install or if somebody was selling pre-finished cement board in 1974. Any suggestions or cautionary notes would be most appreciated.

Re: Anybody familiar with old cement board?


It sounds like you have a product that was an intermediate successor to lath and plaster. It was nailed up like drywall and then a skim coat of real plaster put over the entire wall. There was no need for a scratch coat of plaster as with lath and plaster. It came in unusuaul sizes, something like 4 feet by 2 feet, rather than 4 x 8 sheets like modern drywall or blue board. I think blueboard became the norm in later years. Blueboard is hung like drywall, but then a skim layer of real plaster is put over the entire surface. Blueboard seems to be more popular in the North-Eastern U.S. than in the rest of the country.

Hank Bauer
Re: Anybody familiar with old cement board?

I would say that it is Rock Lath 3/8 inch with a brown coat of gypsum plaster3/8 inch and a white finish coat.If it is Rock Lath it is 16 inch by 4 feet.

Re: Anybody familiar with old cement board?

yup rock lath, and a whole lot cleaner to remove than old plaster and wood laths

Re: Anybody familiar with old cement board?

I appreciate the help guys. I haven't taken much out, so can't verify the 4-foot lengths, but 16 inches is right.
The finish plasterers did an amazing job. It's smoother and more even than a lot of drywall, still.
Will it take a nail, or should I use screws for replacing baseboards and the like?
Thanks again,

Re: Anybody familiar with old cement board?

I've had thick hard mortar over rock lath where it would turn a finish nail. You'll find out for yourself if it's that thick and hard.

Re: Anybody familiar with old cement board?

very true about trying to nail to concrete board, you can try it but i wouldnt use a 18 gauge or 16 guage nail, those two gauges of nails are almost guarenteed to fishhook and come back at you, if you do try to use a finish nailer upgrade to a 15 gauge angled nailer, better quality models will shoot through even light gauge steel stud

TV Listings

Find TV listings for This Old House and Ask This Old House in your area.