Scoop up thinset on the flat edge of a 1/4-inch, square-notched trowel and spread the thinset across the plywood. The History of Thinset. too much thinset. What is it that you want to stick to the OSB with the thinset? Ready-to-use mortars don't require mixing with water and are useful for smaller tiles in non-submerged areas. The thinset supports the backer and the fasteners hold it down. Most thinsets are designed to only work with a concrete or fiber board underlayment, not with wood. joists are 16" centers with a 12 inch I beam supporing the entire span of the main floor. I don't see what the problem is. Secure the cement board with the screws using the pattern directed by … So, all thin-sets are mortars but not all mortars are thin-sets. Sound ok? In this video, learn how to prepare a wood or concrete subfloor for tile, including such steps as checking for dips, installing backerboard, applying primer and thinset, pouring liquid underlayment and when to use OSB or exterior-grade plywood. The thinset is there to fully support the backer. The installation manual for HardieBacker suggests to embed it in thin-set and it should be installed over plywood. Make sure that's adequate first. installed to the RedGard coated OSB with one of STOM’s Cu polymer modified thin set or medium bed mortars. Only make enough thinset that you can use within 20-30 minutes. Depending on how well the thinset was bonded, I would either grind it off (you'll need a pretty good dust containment setup) or use a product like Ardex Feather Finish to smooth that floor up before adding any underlayment. You can use either unmodified or modified thinset under the CBU. That's where a membrane like Ditra comes in. Standard installation is 3/4 OSB with 1/2” hardi-backer installed with thinset and fastened every 6” in the field. It depends on what you are installing. Span of beams under the wood planks is 10 ft and spacing is about 18 inches. Mix thinset per instructions and use modified. Remove smaller patches of thinset using a chisel. It'll act as an intermediary between the tile and the OSB. As such I got the Henry branded stuff and tested on OSB. This is in contrast to 'medium-bed' (up to 1/2" thick) and traditional 'mud bed' installations (1" or more). Then try a test mix of stuff on scraps of the osb for a couple nights. To better understand this modified vs. unmodified thinset talk, you might want to know the “behind the scenes” of this mortar blend and how modified thinset came to life. To test if the thinset is still viable to use, test it with your finger. Latex modified thin sets stick very well to OSB, possibly even better than to ply, it's just not as stable. Re: thin set,mortar bed over 3/4 osb subfloor 3/4" osb is fine provided the joist deflection (span) is good (and spacing.) When you spread thinset over the subfloor, your intention is not really to "bond" it. Then I was going to use thinset with a primer to attach the hardibacker, use the self leveler for the low spots, use the primer you suggested over the hardibacker and self leveler, then redgard, modified thinset, tile. Most manufacturers want you to use modified and so do I. Think of it this way, the thinset is holding the CBU up, the screws are holding it down. It can be installed over a variety of substrates including plywood, OSB, existing vinyl, structural planks, and … It is important to use a very good quality polymer modified thinset to install the ditra on the sub floor. Lift one sheet (leave the rest in place) and spread thinset directly onto the subfloor filling the area left by the sheet (use a 1/4" x 1/4" notch trowel). Planning and patience along with these tips will help ensure that you install the quality of finished flooring you are looking for. All the thin set manufacturers tell us not to bond tiles to OSB. It ALWAYS works. Thin-set mortar for glass and mosaics. If not, throw it out and start a new batch. Mud bed for a shower should have a cleavage membrane under it so the mortar doesn't bond to the subfloor. Dont skimp on the thinset, and let dry over night before installing tile, just to be safe. Specialty Thinset Whatever type of plywood you are dealing with, you need to use a rated thinset mortar that is designed to be used with wood. The underside of an OSB subfloor must be properly protected from moisture to prevent the sheets from warping. Ready-To-Use Mortars. While these could be smoothed over with thinset, they are much harder to manage than the correct solution. Purchased an 1980's cabin in the PacNW which turns out to have OSB underlayment over solid wood planks above a crawl space. But I don’t think that’s what you are asking. The chart is very helpful. OSB is about the second worst underlayment in the world (particleboard would be #1). Nail it off with a roofing nailer on 4-6 inch pattern. Then thinset your tile to the backer. It tolerates all this abuse really, really well, … Thinset mortar is your default tile mortar for most indoor and outdoor applications. I had zero swelling and after it cured tried flexing the OSB, hammering it, plying it off. I applied to the rough side of OSB after keying it in with a trowel tightly. Like was said in a earlier post, all the thinset is doing is filling in the voids and slight irregularities in the OSB. Note: thinset manufacturers do not recommend installing ceramic tile directly to OSB. Glass tiles are 1×2 on a mesh backing. If you are installing cement board or an uncoupling membrane then, yes, you would thinset those down and sometimes to OSB. Dampen the … DITRA is approved for use with ceramic, porcelain, and natural stone tile. You definitely don’t want to adhere tile directly to OSB. Thinset tile mortar has a smooth, slippery consistency, similar to … My question is should I use a glass thin set on the pan and a different modified thin set on the walls. Which, in conclusion, is the best way to do it. Place a 1 inch (2.5 cm) putty knife at a 45-degree angle to the remaining thinset patches. Planning on using ultraflex 1 thinset over 3/4 OSB, then 1/4 hardie, then the same ultraflex 1, then tile. Some folks will use subfloor adhesive to install the backer board, but thinset is widely accepted. OSB panels provide an excellent base for many types of finished flooring including ceramic tiles if careful attention to the construction and preparation of the subfloor is paid in order to avoid costly callbacks. You can have 5/8 OSB and 19.2″ OC joists and it … It’s a very small shower area, 30×60. Thus I would suggest removing the current wood planks flooring, install a 3/4" outdoor grade plywood, thinset and then your HardieBacker (screwed down). Once you have filled the space place the sheet down onto the thinset. If you want to know why- it’s because it pretty much doesn’t matter what the subfloor is under that plywood. How thick is the OSB? The shower walls are a 4×12 subway tile. Back in the days of the early 1900s, tile installers used a procedure known as the “full bed method.” There are tile companies that actually use 3/4″ exterior rated plywood as their standard substrate with a quality modified thinset. Most all the tile I've set has been over 3/4" osb. Thinset adheres to Sheetrock as well as any other surface, but you need to consider the purpose of the area when installing tile. Ditra takes care of that. Do a comparison using construction adhesive or mastic. Proper Way to Lay Ceramic on Plywood or OSB. Premium Mortar. Plywood and OSB frequently have imperfect joints and surface textures. Note: OSB must be protected from water or moisture exposure during shipping and through out the installation process. There are two materials commonly used for laying ceramic on plywood or OSB that are applied before the tile: You should notice the thinset patches breaking apart … The warning is to not install tile with thinset directly to the OSB. ©2012 12/12R My biggest concern would be that some of the OSB is pretty slick feeling on one side and the thinset … It won't get a bond strong enough to deal with the stresses of a direct OSB-to-tile installation. I have read about the evils of thinset over OSB but I … Ready-to-use adhesive for interior tile projects. Thinset mortar is the primary method for installing ceramic or stone tiles onto new surfaces, acting like cement to bond the tiles into their new homes. If the thinset sticks to your finger, it should still stick to the surface being tiled. Thin-set is a specialized mortar that has been designed to be applied as a relatively thin (3/32" or less) layer. When tiling to OSB, the thinset has to try to bond with wood strands or wood chips, and the resin or binder that holds the chips together. Thinset Tile Mortar . When you install Ditra over OSB you are not bonding tiles to OSB, you're bonding Ditra to OSB. Thanks! Thinset is a mortar that is made of Portland cement, silica sand, and moisture-retaining agents. Can be installed on top of concrete, plywood, OSB, gypsum, existing vinyl floors, structural planks, sub-floors, and radiant heated floors; Features a grid structure of square cutback cavities and an anchoring fleece laminated to the underside which is bonded to the surface of the substrate and prevents thin-set from filling the cavities Re: Removing thinset from OSB Stevee-He used a 1/4 x 3/8 trowel instead of a 3/16 v-notch, i.e. Cement board, commonly sold under trade names such as Durock, Hardiebacker, and WonderBoard, is now the standard underlayment used for ceramic, porcelain, or stone tile laid with thinset mortar adhesive.Cement board is used for most floor tile and has all but replaced plywood and drywall backer materials for wall-tile applications in wet areas, like showers and tub surrounds. The thinset is under the board to fill in the voids much like you talked about with the OSB, it is not for bonding, it is strictly a filler. Reply. Tile is porcelain 12 x 12. He took up the old thinset with a cheaper version of what I think Jonathan was talking about. Thinset mortar lays a bed for placing tile. The thinset is not adhering the CBU to the substrate. This will prevent hardening in the bucket. Use a unmodified thinset when laying Hardi over osb, be sure to sand your osb joints level first. Cover an area large enough to place the first backer board sheet. Ceramic, porcelain and rock tiles add beauty and functionality to many areas of the home and give homeowners many design options. Makes a big difference. Thinset (aka the bed sheet) is difficult to get perfectly level, so you need a very strong flooring type to hide any “imperfections.” Ceramic, glass and stone tile floor coverings work great with latex-modified thinset. I do have a question about thin set over a wedi shower pan when using glass tiles on the pan. 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