SUB FLOOR

Help Support House Repair Talk:

rbm328

Well-Known Member
Joined
Nov 19, 2010
Messages
56
Reaction score
11
My house, built in '88, has a plywood sub floor (nailed over floor joists) and then an OSB nailed to the ply (even under hard wood).
I've pulled up all but plywood in kitchen, living room and dining room. We plan to use LVP with an underlayment.

My question is: should I reinstall an OSB over the plywood, then the underlayment and LVP or just lay over the plywood?
Thanks, Rich
 

rbm328

Well-Known Member
Joined
Nov 19, 2010
Messages
56
Reaction score
11
floor joists are 16" OC and 1/2".
the osb was removed because it had mastic stuck to it and we're redoing the floors. last owners put down tile and did a REALLY CRAPPY job
 

joecaption

Well-Known Member
Joined
Jan 8, 2011
Messages
2,555
Reaction score
479
To bad you posted this after all that work, you could have just gone over it with 1/4" multi ply and been done with it.
Still waiting to hear how thick that sub floor is.
It was common long ago to just use a 1/2 subfloor then go over it with something thicker, which makes no since.
If it was mine I'd just go over it with Advantech making sure none of the seam's lined up with the subfloor below, and no nails into the joist below for a rock solid floor.
 

rbm328

Well-Known Member
Joined
Nov 19, 2010
Messages
56
Reaction score
11
was thinking about what I did pull up, formal living room and dining room did NOT have the sub floor, but 80's shag carpet (nasty). only the kitchen and den have / had the sub floor. doesn't make sense to us because they had different heights with transition strips. we want it all to be one level.
Again, is there any reason I should reinstall new sub floor or just go over the ply?
thanks
 

Spicoli43

Well-Known Member
Joined
Feb 23, 2020
Messages
453
Reaction score
318
Location
Montana
was thinking about what I did pull up, formal living room and dining room did NOT have the sub floor, but 80's shag carpet (nasty). only the kitchen and den have / had the sub floor. doesn't make sense to us because they had different heights with transition strips. we want it all to be one level.
Again, is there any reason I should reinstall new sub floor or just go over the ply?
thanks
I just ripped out the carpet, linoleum and old fake wood flooring in the entire house and replaced it with Vinyl. In the bathrooms they had a 1/2 MDF underlayment under the linoleum for some reason, which would not work with transition strips, so I scrapped it. There was no other underlayment on top of the subfloor anywhere else.

I know a builder here, and he had no idea why they did that. There is a reason for everything of course, but ???

I would do a quick quiz of neighbors, maybe find out who the builder was to get a better idea.
 

Fireguy5674

Junior Member
Joined
Dec 14, 2012
Messages
288
Reaction score
70
Location
Central Illinois
If the plywood on the studs is only 1/2", I would want something as a stiffener over it. Also depends somewhat on the type of 1/2" plywood used. How many plies, etc. What ever you put down, I would choose a thickness that allows you to get the common floor height that you want. Use something that will give you a smooth surface for your finished floor. Sorry, I don't have a specific product to recommend.
 
Top