I am finishing some sub-floor work that someone else started, as part of a large remodeling project. They’ve laid 3/4″ Advantech across the joists for most of the room but did not get around to tearing up the last (super-wide) board to finish the floor. Additionally, they sawzalled flush (with plywood) three thicknesses of plates, rafter tails, what have you so that now I am looking at 4.5″ X 19′ of ragged wood. I am really reluctant to spend hours completing the job-that is, sawing and chiseling from top and side in order to make the whole floor the same…is there perhaps an epoxy or some kind of filler that I can use to flush this mess with the surrounding subfloor? Otherwise I envision hours with skilsaw and chisel. Unfortunately the owner plans to put a hardwood floor down, laid in the direction of the plywood and only a wide board could span this mess and wide boards are not in the cards.
Also I’m curious if anyone has found a good sound-dampening underlayment for hardwood?
thanks,
D.
Replies
What's the difference in height between the remaining original board and the new subfloor? Anything to float out this difference will just show through the hardwood unless it's floated out A LOT - not very practile.
Normally I'd use a flooring sander (buffer or eding sander) to grind down any high spots - anything else is a lot of work (wasted time). If the flooring guys will do it rather than yourself it's probably a better idea since they own and use the equipment on a daily basis.
If it's a huge difference I'll make sure any nails and screws are countersunk and run an electric hand plane over it followed by a sander.
Thanks for the input and I knew this would be difficult to explain...
What was left of the original floor (roughly 12' X 19') when I arrived was one row of approx 18" wide planks; sandwiched between the remaining planks and the new Advantech floor was a motley mess, three thicknesses of 2X4, running the length of the room. I have since removed the planks and replaced them with an 18" wide piece of 3/4 Advantech. Which just leaves the mess in the middle.
The mess that is the "meat" in this sandwich was not cut flush. None of it projects above the floor level but it has just been butchered and I'm not sure how to neatly or effectively clean up this mess-short of long hours with skilsaw and chisel-so that a strip of Advantech can be laid. Nor am I sure if this quiltwork of Advantech will be adequate nailing for hardwood. Frankly, I'm tempted to cover the whole floor w/ 3/8" ply. Some of the gaps between Advantech sheets are unacceptable. Does this make more sense? And then use some sort of filler just so that there are no voids, but not for nailing purposes...I can easily adjust for height diff w/ transition piece/molding.
D.
Oh, I get what you're saying now - the different height 2x4's are currently taking the place of any kind of subfloor ply/osb.
It's easy to fill over the top of things like that, but in a floor squeeks develop where two boards rub against each other and the side of a 2x4 and unsuported subfloor edge (between joists) is not good. To fill low 2x4's I'd go with something fairly soft like pine or poplar rather than doug fir so when it's sanded flush with the other subfloor it won't require much sanding.
As for the gaps between boards I think it's hard to beat one of the polyurethane subfloor adhesives to fill the gaps. If it's worked into the gap and by that I mean pressed into the edges of the boards with a putty knife in scratch coat fashion so it can actually get a bite on the edges of the boards, then the gap is filled flush with the surface, it's strong enough to resist minor movement from foot traffic, yet can be nailed into. Of course another option is using an epoxy, preferably with chopped fiberglass mixed in, installed in the same fashion as the polyureathane.
I personally don't like to use cement based fillers if you have to nail into the area since they don't add anything to the situation other than being a non-comprressible filler. If someone is just putting in poly or epoxy without taking the time to scratch coat it into both sides of the gap, then it won't bite and you might as well use cement based fillers.
With hardwood floors coming I'd straight edge the entire floor and see what areas might benefit from filling where low joists/areas are as well as looking at how significant any high joists are. Few remodel floor decks are very flat and flooring guys will normally fly over everything without warning you how bad things are, or even giving a crap....Framing is a framers job, not the flooring guy -they will cover any crap you have without losing sleep over even the worst situations.
For some reason it just doesn't dawn on people that when a 1/8" lump is in the subfloor, that a significant amount will be sanded off the top of the new floor when it's rough sanded so it all looks flat. (or worse you'll have gaps on either side of the lump between the flooring and subfloor and it will always squeek. It's not physically possible to have a wavy subfloor and a good quality hardwood install that looks correct and I don't care how many flooring guys disagree - they can blow that smoke up someone else's rear end. It's sad to say.