Oriented Strand Board (OSB) underlayment suitable for vinyl/resilient flooring?

Hi JShields,

This is the proper forum. Unfortunately, I don't have any experience with OSB flooring. Someone else likely will.

- Chris

Chris, thank you for responding. As indicated by the rather frantic tone of my post, I am scrambling to find this information. However, I am a bit embarassed - hope it does not come across as an E-scream to everyone... I have been following some of the discussions on this site but never posted anything. Again, I appreciate your prompt response. Have a good day :)

just a simple suggestion, go to a flooring store, pick up the installation label and read it. if it doesn't give you the complete answer, call the manufacturer directly. I am a general contractor and occasionally install this type of flooring but I have never and personally wouldn't install directly onto osb. I would simply read the label and follow their instructions. You never know, one manufacturer may have engineered their flooring to go directly onto osb, but another hasn't. I do, however, believe osb needs to be coated first with some sort of floor leveling or patching compound;.

Oriented strand board (OSB) is made of layers of thin rectangular strips of wood (from shredded trees) that are compressed and bonded together with a binder. The grain of the strips for each layer is oriented perpendicular to one another, similar to plywood. The layers are built up with the external layers aligned in the panel direction and internal layers randomly positioned. It is then placed in a thermal press. Although, OSB sounds better than plywood there are some disadvantages. When the OSB panel is exposed to water in excess of its rating the water is absorbs at its edges (due to the inherent porosity of its edges), and swells a little more that plywood. When Plywood panels absorb water, they swell wherever the water is absorbed. OSB will stay swollen while plywood will shrink back to its original thickness, because the compaction force is lessened.

Hence, OSB is rarely used for an underlayment, and never used under vinyl tile.

Vinyl Tile Supplier will advise you best and fastest.

You can visit their website.Ask them-over which?

Or ask at local HOME DEPOT .

Why OSB?

Best lay over masonry direct.

http://www.umass.edu/bmatwt/publications/articles/osb_vs_plywood.html agrees with most of the posts here.

Excellent article! Thanks for posting it in response. I'm going to save it off for future refernence.

OSB or particle board can both be used as underlayment. I have done this personally. However there is a catch!! You have to use a leveling compound before you place any type of tile on it be it vynal or ceramic. You can fin this at any local flooring retailer. There are some that are specifically made for wet environments as well as the self leveling type. Just check it out. Also I do have to agree with one of the above posts. When water or moisture gets into the edges it can cause delamination. This is easily fixed by using a vapor barier underneath it and sealing the edges with caulking.

OSB: I thought all this time it meant Oriental Splinter Board

Quite.

OSB is not a good material to use under tiles. The moisure from the grout will cause it to swell in funny ways, plus it will sag between the joists. Bad economy. You save, what maybe 10% on the subfloor costs? Use OSB on the walls as a sheathing...thats what is made for.

Ceramic tiles....lay down a plastic layer made for it...it will slide over the sub floor, will prevent cracks. You should not make subfloor out of OSB...it sags, and will crack your ceramic tile no matter WHAT you do.

Plywood is only about 10% more expensive. Use that. Fill in any gaps with wood filler, spackle, or plaster. Mix up five gallons of floor leveler and pour it onto the plywood. Use the dimpled plastic for ceramic and slate...you will NEVER have to do warranty work. Glue vinyl, or linoleum, or other tiles directly to the surface of the leveled floor.

If you want to put down hardwood, you can nail right through the floor leveler. I don't recommend gluing hardwood, but I HAVE seen it done. Not sure if the glue would allow it to shift the teensy tiney amount it must shift to keep from splitting and cracking. Anybody with first hand knowledge?

I base this on personal experience. Your mileage may differ.

Yusef1

stag@cyberus.ca

OSB not recommended for underlayment due to uneven swell from moisture due to spills.

...which is a mystery as in the UK, if one orders a new garden shed as a kit of parts, the floor will be made from it.

Hi in Australia it is common to use either fibro cement board, (used to be asbestos cement board before asbestos was a dirty word) or Masonite which is a compressed hardwood fibre board. It is made in 1 metre square sheets x 6mm thick and nailed/ glued at 150mm in each direction. The joints are butted tight and sanded. There is always a small gap at the periphery of the room (mm) for expansion. This method has been used for years on strip hardwood flooring, chipboard flooring and poured concrete slab flooring. The finshed surface can be vinyl tiles or sheet vinyl, either is successful.

coben

Subfloors and underlayments serve as structural platforms and as a base for flooring products. Osb and plywood are equals structurally, but flooring manufacturers make different recommendations regarding their use as a substrate.

The National Oak Flooring Association (NOFA) in Memphis recommends either 5/8-inch and thicker plywood, 3/4-inch osb or 1-x6-inch dense, group1 softwood boards installed at a diagonal under hardwood flooring. The NOFA recommendation is based on research conducted by Joe Loferski at Virginia Tech, Blacksburg, VA. In his study, Loferski simulated what happens on a real construction site. He built several full-sized floors out of boards, plywood and osb and weathered them for 5 weeks before installing hardwood flooring. Finished floor systems were cycled in an environmental chamber to simulate the changes that occur in summer and winter months.

The study showed that solid boards installed at a diagonal were far and away the best system. Statistically, 5/8-inch plywood and 3/4-inch osb worked the same. But two significant observations were made during the study: Some of the plywood delaminated during the weathering experiment and new patches had to be spliced into the subfloor system. Also, researchers learned that the best floor of all was the control specimen, which had been protected from any weathering. This speaks volumes for the importance of protecting materials during transport, storage and early stages of construction.

If you are planning to use osb as a subfloor OR underlayment for your next tile floor, you may want to think again. Joe Tarver, Executive Director of the National Tile Contractors Association, Jackson, MS says, " Osb is not an acceptable substrate to receive ceramic tile, period!" NTCA lists osb, along with pressboard and luan plywood, as "not acceptable" in its reference manual. It has to do with thickness swell. They feel that if osb gets wet, it transfers stress and causes the tile to fail.

The Resilient Floor Covering Institute, a trade association that represents manufacturers of vinyl sheet-flooring and tiles, also puts the nix on osb. RFCI installation specifications recommend plywood as an underlayment material. Osb is acceptable as a subfloor material. Manufacturers have not seen a deluge of failures due to the use of osb under resilient flooring. However, they have received complaints of edge swelling that has telegraphed through their flooring products. Manufactures feel more comfortable guaranteeing their products when they are installed over plywood.