sturdi floor over sub

[partst]

I asked a question last week but didn't get an answer. I'm putting 1 1/8 sturdi floor over 1x6 sub floor which is old and brittle. should I nail or screw it to the 1x6? Also since the sturdi floor is tongue and groove, do I glue these joints and still leave a small gap on the ends? And again why not attach to the floor joists instead of just the sub floor? Thanks again

[Tilebri]

With the advantec going over the plank, I'll guess you are preparing for ceramic and the reason you do not want to screw into the joists is that the underlayment layer helps to isolate the floor from the supporting structure. If you screw the underlayment to the joists, then all the movement is transfered up to the floor. With 1 1/8" advantech, I'd be ripping up the plank floor anyway. No need for all that build up at all. A bead of construction adhesive would only be used if you are isntaling over the joists, not if you are using it as an underlayment. By the way, for a tile install, yo only need to use 1/2" bc or better exterior ply over the plank floor, then cement board. The combination of the 2 will not be much more than 3/4". If you planned on not using a cmentboard or other underlayment over the advantec, then you should know that thinsets will not bond well to osb and can only be used under cment boards and not as a setting bed. And old and brittle planking will not give the floor the support it needs either. Old and brittle means it takes a trip to the landfill.

[partst]

The reason I don't want to remove the sub floor is because it is under all the walls, interior and exterior. The height is not a problem because the kitchen floor is 9" lower which I am going to bring up to the same height. Strange, but the center of the house is cement slab, and both end are conventional. I think the house was built in seperate stages. When I said brittle, I was refering to how well nails would hold. Put down 2 pieces of the 1 1/8 plywood and it seems to be very solid. :thumbup:

[Doug Aleshire]

partst,

Just my 2 cents worth. Wouldn't it better to remove the planking and then apply your new sub floor. Easy enough to cut out old with circular up to the walls as close as you can get then sawzall the remaining? Then install new so there is not chance of flexing?

I don't like going over something that is old and not as sturdy or rigid.

Just a thought

[partst]

Thanks for the input Doug. I didn't mean to imply the floor is not sturdy, there is no bounce or loose boards. I was just concerned about nailing. The nails went in solid so I think it will be fine.

[Doug Aleshire]

partst,

Just wanted to make sure you were not doing all this work and be disappointed in the end.

Seems like you got it under control.

Happy Easter!