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tile installation dilemma

I have an exising room that has engineered hardwood glued to the sub subfloor. The hardwood was damaged and I cant repair or find a match so I was thinking I would like to tile. However my floor joists are 24" on center and my subfloor appears 3/4". What should I do to make this floor acceptable to tile. I figure I will likley need to cut out the entire floor, but how to i make the subloor stiff enought w/24" spaced joists.

Re: tile installation dilemma

More info is required such as the span, the size of the joists, the species of the wood joists, etc.

You can run the info thru this calculator to get a basic answer.

I'd personally like to see 1 1/4" of subfloor for ceramic tile on 24" OC joists......but those joists must first qualify as concerns deflection.

Re: tile installation dilemma

I go by the same rule of thumb...1 1/4" of subfloor, then a tile backerboard of your choice, then tile.

Re: tile installation dilemma

Whats on the floor below it as far as partitioned walls...in other words, how long are the spans of FJ's with no support under them?
Whats the room under it and if the said floor is over about ten feet or so with no partitions below it can you add a girder using lam beams below and rock the girder to match the ceiling or would that look stupid in that room?
Youi really need to give us some dimensions to work with here so we can help you better but more than that you need an engineer to let you know whats acceptable for what you have.
Another choice depending on whats below is to build two temporary walls below and cut accross the said FJ's and add a flush lam beam girder tying in the existing FJ's with tekos. This way there'd be no drop in the room.
Not enough info here to really help you.
Also...one layer of 3/4" subfloor is not enough...as Goldhiller and others said you need a minimum of 1 1/4" of subfloor.
You also may want to think about using Ditra instead of cement boards on the floor under the tile.
Sure you don't wanna put down another wood floor? LOL

Re: tile installation dilemma

Ok, so this sounds like tile is out. I am also considering replacing the engineered w/more engineered or solid hardwood. So now the question would be that the old engineered is glued down to osb. I can pry up the old hardwood, but then have glue everywhere, is there an altrnative to cutting the subfloor out and starting over. The room is about 15x15 1st floor room, if I have to replace the subfloor, do I need to run stringers between the engineered joist just under where all 4 interior walls are so the floor doesnt flex there?

C Ed Wright
Re: tile installation dilemma

Please also include the condition of the underside of that floor, i.e., is it open or not; what is the ceiling below, if any, made of; if open, is there any blocking or bracing, and its spacing, etc.,; and so on, because these things also serve to stiffen a floor.

But why would anyone glue down an engineered floor? That and 24" o.c. joists are red flags in my mind, that suggest forgetting about tile and consider overlaying the existing floor with another layer of either solid or engineered strip flooring. If another 3/4" seems too much of a height increase, 3/8" thinkness is also available.

If you just want "Cheap & Cheerful" [as a former neighbor used to happily announce was her decorating style], check out the 12"x12" self-stick prefinished real wood parquet tiles available at various home centers. These are suitable for installation by both pros and DIYers. I also recommend them to landlords fed up with recarpeting each & every time each tenant moves out. (I also recommend an additional coat of poly after installation to minimize penetration of spilled liquids between its myriad joints.) But while Pergo and its knockoffs may look pretty good in the store, they look like hell in the home.

C Ed Wright
Re: tile installation dilemma

I had an additional thought that might help if you are certain you want to tile it, dependinf on wherther you have Tec tile installation products available in your area.

Sand the finish off the engineered hardwood, then screw & mortar 1/2" CBB using Tec Superflex (gray), taping joints with fiberglas mesh. Also set the tile with the same mortar. The 3/4 subfloor plus the glued-down engineered hardwood yeild 1-1/2" tiotal bionded substrate that ought to be more than sufficiently stiff even at 24" o.c. The addition of the CBB & Su[erflex will give the floor almost a poured-slab feel.

However, joist stiffness is still a question easily answered by literally jumping up and down on it. Try one person, then two in unison, then three, etc., and see if it starts jumping up and down with you -- a sort of trampoline effect. If you don't get a noticeable amount of bounce you're good to go. All wood floor joist construction will flex and bounce a tiny bit -- that's why it is literally less bone-jarring & tiring to walk on a wood floor than on concrete. It's just that a little too much flex cracks grout, and a little more cracks tile.

Re: tile installation dilemma

Along the same line of thought, but on the other side of the fence..... I have several of the old Parquet Wood Tile that were previously used, a few broken, but most in good shape. I want to put them down over a rough concrete floor in my shop. What do I use as an adhesive?

Re: tile installation dilemma

They make an adhesive specifically for gluing parquet flooring over concrete. You can find it anywhere that parquet flooring is sold. It' a really gooey mess to work with, but it holds well, provided you don't have a moisture problem. Although the product isn't recommended for below-grade, I've used it successfully. To check for moisture, tape a 2' square piece of visqueen to the floor. If there's no sign of condensation under the visqueen after 24 hours, you're good to go. If the concrete is really rough, you'll have to skim coat it with a floor levelling compound, but then you'll have to wait for this to cure, or the adhesive won't stick.

Enjoy your new shop floor. It's a lot easier on the knees and back than concrete.

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