gaps in subfloor

[krogers]

I am renovating a room that has an old shiplapped floor. Planks are 1x6 nailed to 1x8 joists. The floor is so old that the boards have shrunk considerably. There is a 1/8 to 1/4 gap between most. And one gap down the center of the room that is about half an inch wide. I am thinking those gaps are too wide even for the carpet I want to add to the room. I don't want to rip up the current floor and put down 3/4 ply. I am just going to patch a couple of broken planks with ply. I am thinking of adding a 1/4 or 3/8 ply over the top to smooth everything out. The only height problem would be the bullnose piece at the top of thestairs. I figure I can pull the bullnose off and shim underneath. I intend to carpet this room when I am done. What do you think of this idea? If I go with the ply should I just screw it down through the floor to the joists below, or should I use adhesive like liquid nails as well? Thanks for you help.

[Hellrazor]

If the floor squeaks, make sure you fix that problem before you add another layer of wood. Yes you should screw the new plywood down (unless you have a framing nailer and 8d ringshanks laying around).

[JSCOOK]

IMO, I'd use 3/8"ply over it and use both an adhesive and screw to eliminate or minimize squeaks and creaks ..

I am renovating a room that has an old shiplapped floor. Planks are 1x6 nailed to 1x8 joists. The floor is so old that the boards have shrunk considerably. There is a 1/8 to 1/4 gap between most. And one gap down the center of the room that is about half an inch wide. I am thinking those gaps are too wide even for the carpet I want to add to the room. I don't want to rip up the current floor and put down 3/4 ply. I am just going to patch a couple of broken planks with ply. I am thinking of adding a 1/4 or 3/8 ply over the top to smooth everything out. The only height problem would be the bullnose piece at the top of thestairs. I figure I can pull the bullnose off and shim underneath. I intend to carpet this room when I am done. What do you think of this idea? If I go with the ply should I just screw it down through the floor to the joists below, or should I use adhesive like liquid nails as well? Thanks for you help.

[billwmeyer]

Before you put down your plywood, put down a layer of tar paper. This will keep drafts down, keep your floor a bit warmer, and deadens some noise.
Bill

[krogers]

tar paper.....

Bill, I have considered that idea, but mainly for sqeaks, not drafts. I am worried about wood on wood. So which is better for sqeaks prevention? Ply on tar paper with screws, or ply with adhesive and screws?

For more background, the current floor has been in place for 75 years. It is insulated below the floor with rockwool blown in. With quite a bit of settling from what I can see. The ceiling below this space is plaster over wood lathe. There are bedrooms below, so sound travel is important.

[JR]

For more background, the current floor has been in place for 75 years. It is insulated below the floor with rockwool blown in.

Is there any chance there's asbestos in that insulation? I'd definitely go with the tar paper suggestion in an effort to isolate that stuff. Definitely do not do anything to stir it up!

JR

[krogers]

Never say never....

Is there any chance there's asbestos in that insulation? I'd definitely go with the tar paper suggestion in an effort to isolate that stuff. Definitely do not do anything to stir it up!

JR

Sure, there is always a chance. I have never bought and used rockwool insulation myself. Only fiberglass bats. So there is a chance this stuff is asbestos. But I have had several contractors in the space and none of them every mentioned a concern that it was "the bad stuff." A plumber, electrician, and a whole team of HVAC guys have rolled around in the stuff that is off the edge of the floor and under the rafters. I don't intend to touch the stuff. Part of the project will be to roll some unfaced fiberglass over the exposed insulation running perpendicular to the joists.

[billwmeyer]

I really don't know what the best option is, adhesive or tar paper. I would think that the tar paper would be cheaper. I am sure it is easier. Good luck.
Bill

[drunkcat]

I had a similar situation. I went the tar paper and 3/8 ply route and its great. It stiffened up the floor quite a bit. Make sure you use good screws to fasten down the ply. I went with the colored decking screws; others will break off.

[krogers]

Screw Length?

What size screws did you use/recommend? 3/8 ply over 3/4 deck and into the joists sounds like a 2 1/2 screw.

[TheRic]

I would make sure the old wood is very secure. Even if you screw something on top down into the joists it will still squeak. Think of it like putting new paint on old paint, if the old is not solid, then the new won't be.

Above my office, in the basement, is the kitchen (we moved in 4 years ago). Did some digging into what is on the floor, must be 5+ layers of STUFF. I can see where they tried to fix the problem, on different layers and/or at different times. It squeaks when the 30 lb. grandkids or a 40 lb. dog walks on it, not to mention an adult. I'm talking about ripping the WHOLE thing up to the joists and doing it correctly!! It won't be cheap or fun, but the problem WILL be gone.

I would not worry to much about asbestos. Touching it is not a problem. Breathing in small (minute) particles over a long time is the problem.

[onedash]

1X8 Joists? was that a typo?

[TheRic]

1X8 Joists? was that a typo?

Good catch, missed that!! Must be a typo, or that IS/WILL BE the cause of the squeaking floors. Can't believe the wood shrunk THAT much

[krogers]

Nothing get's past you guys.

Yes, that was a typo. They are 2x8 joists.