I’m in the process of remodeling the basement in my 57 year old house. I’m taking the time to shore up some sagging joists but I’m wondering what I can do to fix the squeaky floors in the rooms above. Subfloor is all 1 x 6 set on the diagonal.
I have fixed squeaky floors in clients’ houses but that was from the top. I’m thinking 1/2″ or 3/4″ plywood cut to fit b/t the joists and secured with construction adhesive and screws (long enough so as not to resemble punji sticks in the living room).
Am I overthinking this??
Replies
If you've got joists that are actually sagging, the whole floor might be underbuilt. How bad is that sag?
Rebuilding my home in Cypress, CA
Also a CRX fanatic!
The joists are not in that bad a shape. I assumed they were in a lot worse shape. Now that they are all exposed, I used my laser to check for deflection and found out I was wrong in my assumption. No more than 10% of the total. 2x10's with a maximum span just shy of 14'. They are notched at both ends and set on a 2x4 nailed to the 4x10 beams. They are even done that way at the rim joists. I have the original blue print that show 2x8's. Not sure how I ended up with 2x10's, but I am very thankful I did. There is some splitting at the notched ends -- amazing what happens when you drill holes for wiring within 3 or 4 inches from the ends!
I have done the squeak test with a handful of shims and found that there are hardly any gaps at all. I'm wondering if the problem has more to do with how the hardwood floors are fastened. There are a coulple of areas that have cut nails that I have to hammer in every couple of months. This also makes me think that the floors weren't fastened as well as they should have been.
I also talked with an expanding foam sub that said they have had success lessening squeaky floors by spraying an inch or two of foam on the underside of the subfloor. I'm sure this would be a large cost and wouldn't solve the poorly fastened hardwood floors problem because it would only bond to the 1x6's and the felt paper underlayment. This would help the sound transfer to the basement, I assume.
Knowing all of this -- any insight?
I suggest a two step approach.
First, you want to minimize the rubbing of the diagonal subfloor on the joists. Lay a thick bead of PL Premium along the top edge of each joist so it glues the diagonal subfloor to the joist. Do it on both sides of each joist and smooth the bead with a gloved hand so the glue fills any gaps. Be sure to wear goggles and a hat. Also glue the butt ends of any joints in the diagonals that do not fall over a joist. This will get rid of most of the subfloor to joist creaking and it might just stiffen the floor a bit.
Second, after the glue has dried, have someone walk around the floor above you with a walkie talkie to try to locate any creaks that are more likely due to the floorboards rubbing on the subfloor. Git yurself some round washer head screws from McFeeleys http://www.mcfeelys.com/subcat.asp?sid=237 that are long enough to bite into the floorboards when screwed up from below, but not so long as to penetrate the top of the floorboards. The screws should also have a smooth shank (no threads) through the portion of the screw that penetrates the subfloor. I think the ProMax screws will fit the bill. The idea is for the screw to pull down the floorboard tight to the subfloor, and this should be done while someone is standing on the floor above you (and wearing good shoes). You can also drill a shallow pilot hole in the subfloor to enhance the clamping action.
I've used both these approaches with good success to eliminate the majority of creaks, and now is the right time to do it.
Billy
With diagonal 1x subfloor, there were often two layers of subfloor laid, one on top of and at 90 degrees to the other. Then the finished floor was laid on top of that. This gave a total floor thickness of close to three inches...but also allowed a lot of space to develop between the various layers as fasteners loosened over the years due to floor flexing (those sagging joists you spoke of).
You'll need to tighten up those layers to get rid of the squeaks. An easier way than screwing up through the bottom is to get a pair of walkie talkies and have a partner walk around upstairs so you can find the squeaks down in the basement. When you find a spot, drive a cedar shim between the joist top and the subfloor at that point. This will compress the layers together and usually stop or reduce the squeaking at that point.
Don't drive the wedge in too far, or you'll raise a hump in the floor. Just go in far enough to eliminate the squeak--or as much of it as you can. Then pin the wedge in place with a finishing nail or 1" box nail.
Dinosaur
How now, Mighty Sauron, that thou art not brought
low by this? For thine evil pales before that which
foolish men call Justice....
I've never run across that before. I know my house just has the one layer of 1x6's. I have cut out some areas in the past and exposed the cross section.
See the e-mail I sent xxPaulCpxx in regards to the squeak test.
Any thoughts on the spray foam insulation?
Forget the foam. Waste of money.
Interesting that you have a single layer of 1x6 but run on the diagonal. Are those boards t&g spruce? When I see those, they are usually laid perpendicular to the joists, one layer only.
The double-layer diagonal is usually made from unplaned 1x in 4's, 6's, even 8's. I have seen widths mixed in the same floor. Note that when this 2" thick subfloor was used, the joists were spaced more widely than is common today; sometimes as much as 36" o.c. Dinosaur
How now, Mighty Sauron, that thou art not broughtlow by this? For thine evil pales before that whichfoolish men call Justice....
To assist the person above, use a magnetic stud finder while you hold a crow-bar beside the joint
Phill Giles
The Unionville Woodwright