# type of screws for securing subfloor?



## debiasio

What type of screws should I use for securing a subfloor? I've read anything from ring-shank nails to just regular wood screws. 

The floor was constructed by first sistering new joists to the old ones, nailing and gluing 1x4 stock across the joists about 8-10" apart, then finally nailing and gluing 3/4" plywood on top. Is it necessary to screw through the 1x4s, or can I go directly through the joists?


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## woodman58

I would suggest using a premium wood screw for interior use 2 & 1/2 inches in length (course thread). You don't need to screw into the joists unless you just want to. The 1x's are already secured. I would suggest that you use liquid nail between the 1x4's and the ply.


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## Floor Doc

Actually you don't want to screw into the joists .
Is the 3/4" plywood already glued and screwed to the substrate ? 
PL400 is a much better adhesive then Liquid nail .
You can get it in large tubes at HD for around $6.00 a tube . 
Check the dates on them , they tend to gas up if they been laying around for awhile .


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## tcleve4911

I use GRK screws


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## JazMan

There are many good screws you can use to install plywood to the subfloor. Add deck screws to the list. Just do not use drywall screws, as many do cuz they're cheap.

The subfloor should be glued and fastened to the joists. The underlayment, is NOT glued to the subfloor AND is fastened ONLY to the subfloor. Glueing the underlayment to the subfloor can actually create more bounch since it can create voids between the two surfaces.

Jaz


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## debiasio

Floor Doc said:


> Actually you don't want to screw into the joists .
> Is the 3/4" plywood already glued and screwed to the substrate ?
> PL400 is a much better adhesive then Liquid nail .
> You can get it in large tubes at HD for around $6.00 a tube .
> Check the dates on them , they tend to gas up if they been laying around for awhile .


 
It's glued to the 1x4s. I used PL Premium for the adhesive. Seems pretty solid. 

Thanks for all of the suggestions. I have a good idea what to use now.


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## JazMan

> It's glued to the 1x4s. I used PL Premium for the adhesive.


This is the step that is not recommended. Next time fasten only, no glue between subfloor and underlayment.

Jaz


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## debiasio

JazMan said:


> This is the step that is not recommended. Next time fasten only, no glue between subfloor and underlayment.
> 
> Jaz


OK. I'll keep that in mind. Hopefully the once I screw down the plywood, it will be solid for a long time.


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