Repairing Wood Floors Nailed Over Sleepers
I have an older home with some recent remodeling that has been done. The original hard wood floor is on 1×4 sleepers. From the basement looking up on the underside, , floor joists ( 2″X12″ @ 16″ ) then 1X6 nailed as a subfloor, then 1X4 sleepers spaced every 6-10 inches. The hard wood floor is nailed to sleepers. Sleepers running same direction as floor joist. Remodeled part of home has multiple layers of plywood to match existing floor. Old part of floor is bouncing between sleepers in some parts causing wood floor to separate in some spots. Is there any remedy to repair without ripping all out and installing a proper sub floor? The basement is all open from above. I was thinking of trying to inject some spray foam from below or something similar. Any suggestions appreciated.
Andy MMP
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Replies
AndyMMP,
Foam will likely expand and aggravate the problem. And it is pretty irreversible and will be squishy. If the flooring nails are letting loose from the sleepers, top nailing is the quickest if least desired option. Hardened finish nails set at opposing angles will lock down errant boards if you manage to get the sleeper and not air. Putty the holes after setting the heads. Pre-drill the holes in the hardwood to prevent splitting.
If the sleepers are going loose from the sub floor thanks to repeated dry-damp cycling, then pulling down the sleeper from below is a better option. Selecting screw length is going to be the trick. You do not want to try setting screws into the flooring except as last choice.
Being oak or maple it will require self drilling screws or pre-drilling to avoid the push effect created by going through the boards below first. If you have any scraps of pine and flooring, try holding the two pieces of wood together with just your hands and then set a screw through the pine toward the hardwood. Most likely you will experience the "push" effect of the screw threads advancing well in the soft wood and not so well into the hard wood. Even the best self drilling screws have a hard time not doing the same if the two woods are not firmly clamped together. The screw tip will tend to jack up the harder wood. There is also the risk that a self drilling screw could advance itself faster than expected and poke through the finished side of flooring.
It is VERY important to note is that electrical conduit may be present between or adjacent to the sleepers. In the Chicago area, conduit has been code in many localities for decades. In two of my rehabs, the conduit was laid between the sleepers to reach across the floor to the next wall outlet location. BX may also be present. Use a metal/current detecting wall scanner to check for their presence before doing anything with nails or screws.
If you are lucky, the builder cheaped out an did not put down flooring paper over the sub-floor and you might be able to see the metal tubing via the gaps. The sub-flooring was put on at a 45 angle to the joists in good work from the 30's to 60's before plywood and other sheet goods took over. The paper was to reduce dust from falling thru the gaps and to help keep the sleepers from squeaking.
I would consider ripping 3/4" plywood or Advantech as a sub-subfloor to fit between the existing joists, glue it into place with construction adhesive and fasten 1x2 cleats to support the new sub-subfloor. It's tedious but I've done it and it's not bad once you get going. Before doing this you might screw up through the existing subfloor into the sleepers to minimize squeaks.
I agree with onslow that injecting spray foam could result in problems.