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Securing plank subfloor to joists?

27K views 83 replies 10 participants last post by  duffman56 
#1 ·
I have purchased some #10 2" screws to attach our t&g plank subfloor before tiling.

How often do I need to screw the planks into the floor joists? Joists are 16" oc and planks are 3-1/4" wide. So, screwing every other plank would mean a screw every 6-1/2". Is this adequate, overkill, or a good plan?

1/2" ply to go over t&g, attached with #8 1-1/4" screws, then Ditra, then the tile. I've received advice on amount/spacing of the 1-1/4" screws, but not the 2".

Oh yes, I consulted the Ditra handbook, which was helpful regarding the method, but said nothing about how often to screw the t&g.

Thanks to everybody for your help!
 
#83 ·
JazMan said:
Duffman,

Have you confirmed that the movement is because of the joists and not the planks? If the joists are deflecting too much they must be a poor quality in poor condition. 2x6 spanning such a short span should be fine.

Adding the plywood is not gonna improve the joists, just the subfloor. You need to figure out where and how much deflection there is.

When you add the new plywood underlayment make sure you do not buy sheathing. You were just referring to $12 a sheet ply which is the wrong stuff.

Jaz
Jaz, there is nothing wrong with plywood you want to drag it through the mud by naming it sheathing it's meant for what it does and it works.
I always use unsanded cdx and then sanded to tile on
for subflooring. Hasn't failed me yet :)

He has steal I beam that holds up the joists he's as good as sound, your going to have bounce with 1/2 on old planking.

Raising to 3/4 will tighten up the deflection believe me I have been down this road so many times.
 
#84 ·
Had the pro come over tonight. He said we are doing things right and we should be fine. I showed him that the things atop the deep freeze jiggled somewhat when I jumped from a few feet away. He told me this was normal and that every floor will have some give to it. What a relief!
 
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