Aspenite subfloor

Hi,
I am currently in the middle of laying porcelain tile in a small (5'x6') bathroom and entry hall. We have cut the cement backerboard and were deciding whether to use mortar under it when we read that you should not install over aspenite. We have 1/4" tile and 1/4" backerboard and have already cut back the door frames. Would you recommend laying plywood or would it be safe to lay the backerboard over the aspenite (and maybe only screw it down and not use thinset)? The tile floor will transition to a carpeted family room (I am assuming it is also on aspenite). Thank you.

The Aspenite needs to be removed. What's under that? If it's a suitable subfloor you can spread your thinset and install the backer board. Spreading thinset under ALL CBU's is NOT an option, it's required.

If the subfloor is too thin or in bad shape, you can add a layer of 3/8" or thicker underlayment grade plywood, and then the backer as above.

Jaz

The floor consists of 23/32 aspenite. There is nothing above it or below it. It previously had carpet on it. Removing the aspenite is not an option for us. Are there any other solutions to laying tile on this floor?

On second thought--------. As you know, Aspenite is a species of tree. In some areas some refer to both OSB and particle board as Aspenite, which only confusses everyone. Can't be both.

If you subfloor is particle board, it's recommended that it be removed and replaced. Particle board looks like a bunch of tiny chips of wood that are glued together. This is bad.

OSB, (oriented strand board) is often used as a subfloor, and IF it's subfloor quality it's fine. Apparently your subfloor is an older one, and it might be either. Please describe it for us, or can you read the markings from underneath?

Jaz

The floor is defenitely not particle board. It has large flakes of wood going all directions. Maybe OSB is the appropriate term for this type of board. The house is 14 years old.
Here are the markings on the subfloor as seen from the basement:
Weyerhaeuser
Sturdi Wood
Structural Panels
______APA______
Rated Sturdi Floor
24 OC 23/32 in
Sized for Spacing
Exposure 1
_____384_______
PS 2-92 Single Floor
NER-QA 397 PRP-108
HUD-UN-40C
Construction Sheathing
1F24
17. 5 MM
2 384
CSA 0325

I've never seen particle board with those types of markings on it.

Larry,

Your subfloor is definitely OSB. If it's in good shape and feels solid, you can install the backer. Make sure your use the proper thinset and mesh tape etc.

Jaz