[jduke44]

Hey guys, quick question. I'm going to install self-adhesive tile flooring in our bathroom. I was going to put either a plywood or luan subflooring first then apply the tiles. I was wondering when I nail the subfloor down, do I use anything to cover the nails and any gaps in between the sheets of subflooring. The bathroom is only like 6' by 6' so I don't have that much to cover. Thanks.

[ballengerb1]

We have to assume you already have a subfloor down that is accepable thickness. Luan is kind of old school but you could use it, I'd recommend 1/4" Hardiebacker glued and screwed. Either new sub floor needs 2-3 coats of an adhesive primer if you want to the tiles to stick (same ailse where you got your tile.) Seams for both floor should be set with modified thinset which is usually used to set ceramic wall and floor tile, spot the nail head too. Again I would not do what you describe but these are the steps if you go ahead with your plan.

[jduke44]

Thanks for your response. I am not sure what you mean when you say acceptable subfloor. I now have rug and will not know what I have until I rip that up. I think what I will find is the floor that rests on the floor joists and maybe another floor on top of that. This is a first floor bathroom that has basement under it. Ok, so you are saying luan is old school. The reason I was going to do this is because this is what I heard to use. Is the Hardiebacker a lot more money to use?

You gave me this info based on me using luan right? What if I use the Hardiebacker. Would I need to do the same thing or what would I do? Thanks.

[ballengerb1]

Hardiebacker is about $8 for a 2x5 sheet. You should lay it in a bed of modifed thinset$40 for 3.5 gallons but you need much less. The special screws for Hardiebacker are $8 for 150 and youl will use nearly all of them. Both Hardiebacker and luan need to have their edges/seams sealed with thinset and you can patch the nail heads with that too. I hate nailing any sub floor because nails can and frequently do back out over time. An acceptable sub floor already down means that you have two layers of 3/4 or 5/8 plywood under the carpet. If you sub floor is thinner than that then switch to 1/2" Hardiebacker.

[jduke44]

Ok, one last question (hopefully). If I am using the thinset for the backer that will act as the glue then screw it in, right?

[hkstroud]

Let me put my 2 cents in here.

Remove the carpet and see what kind of surface you have. If it is clean and smooth, lay you tile over that.

If you think you need a new clean surface you can put down either the Hardibacker or plywood. Use screws and construction adhesive. If you use 1/4" material and it were me I would probably only use construction adhesive. By the time you countersink the screws there is almost nothing for the screw to hold to. Believe me the adhesive will hold, why bother filling screw holes.

Forget the luan, too thin (only 3/16), nails pull through and not enough material to counter sink for screws.

[ballengerb1]

Yep, glue it and screw it, words to live by when using sub flooring.

[the1unv]

I always fill screw holes... over time they will show. I would recommend at least two coats of primer, its $10.00 a gallon and worth it. If you check with your supplier you will find that using lauan will void the warranty of most floor tile. Its to thin and not nearly enough plys. When filling nail (or screw) holes and seams I like to use rock hard wood putty. It comes in small cans for your type of project. You can mix only what you need. Mix it thin and pull it out tight with a putty knife. It drys quick, don't leave big ridges, it doest sand real easy. This is just my opinion but it works well for me.
Mike

[jduke44]

Hey thanks guys. Good info.