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gwilkrrs
bringing a bathroom subfloor up to the proper height

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my addition is built with a slab on grade- it will have 3/4" plywood then 3/4" hardwood in th rooms- this means the bathroom subfloor is 1-1/2" too low from finish floor height. i am wondering what the best way to make this distance up is? i will be putting heat mats in the floor also. should i use mortar to build up the subfloor a little or just a thick setting bed when i set the tiles? i think she wants the small octogon tiles so that would be tough........ thoughts?

MLB Construction
Re: bringing a bathroom subfloor up to the proper height

1-1/2" is the perfect height to lay down sleepers. cover the floor with pressure treated 2x4's lay them down on the flat. for some added strength you can space them at less than 16" on center, maybe 12" or 14".

gwilkrrs
Re: bringing a bathroom subfloor up to the proper height

sleepers would put the top of the sleeper at finish floor height- i only have 1-1/2" total from slab to top of finished tile work- i am guessing 3/8" to 1/4" for the tile and 3/8" for the setting bed.... i am trying to determine what to make this diference up with....

MLB Construction
Re: bringing a bathroom subfloor up to the proper height

sorry, i misread your post.

i would install 1/2", 5/8" or 3/4" PT plywood over the slab, depending on how thick your tile is. cover it with 1/2" Hardibacker which will bring you up to either 1", 1-1/8" or 1-1/4" and leave you 1/2", 3/8" or 1/4" for tile.

it's an awful lot of work to bring an entire floor up 3/8" with mortar and it might not be perfectly level. plywood and hardibacker is quick, easy and plenty firm enough for any tile floor.

gwilkrrs
Re: bringing a bathroom subfloor up to the proper height

so I am moving slowly on this project- the wood floors are now complete. the finished floor is 1 1/2" higher then the slab as suspected. the tiles are a touch thicker then 1/8" he said (1" hexagon sheets) the heat mat is 1/8" and I think the thinset for tile is 1/8" so that's 3/8" less then 1 1/2" I need to make up so that's 1 1/8" to make up. I was originally told to do a drypack bed to make it up but I am thinking 2 layers of 1/2 durorock staggered to make it up with thinset between the slab and sheet and between the sheets........ thoughts? I am waiting for the tile to come in to verify all thicknesses but these should be close......

Mastercarpentry
Re: bringing a bathroom subfloor up to the proper height

Either a "mud bed" or the durorock will build up to what you need. Being that this is going to be heated, I'd go with the durorock as I feel it will be less likely to crack over time with the thermal changes involved.

Phil

HoustonRemodeler
Re: bringing a bathroom subfloor up to the proper height

CBU (ceement backer units, ceement board) must be set over thinset then mechanically fastened to the substrate as per the manufacturers instructions.

You'll find drypack to be a cheaper, faster, better end product. The guys on the John Bridge Tile Forum are correct in their advice.

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