We have an 100 year old home. The main level floor has no sub-floor. It is in good shape and stable, but there are a couple slightly flexible areas, and a gap or 2 in the boards. I have pretty good access to the underside from the basement. Any suggestions on how to reinforce this floor from below? Also thinking of insulating, so ideas also welcomed for that. Thanks!
Old house, no subfloor; how to reinforce?
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Thanks! I should have been clearer. The joists are in excellent shape - the originals have been reinforced with new (daughter?) joists bolted alongside by the prior owner, so the structure is strong. However, a few of the floorboards edges have split off, leading to some slits of daylight, and a slight "give" in a couple of floor sections. It's the old floorboards themselves that have the slight flex. I was thinking of cutting strips of plywood to fit from underneath those sections for support, mounted with a cleat on each joist. There's a full basement below, with an open but low ceiling, maybe 6 1/2 feet, so plenty of room to work.
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For the floor to "give" on strong joist the flooring lumber evidently isn't touching the joist. From below shim those areas with cedar shingle material as you would a door jamb during installation.
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37,499 Posts
How about a picture so we can see what your seeing?
So far we have no idea what's there?
Hardwood, 1 X 6's ?
What's the plan for the finished flooring?
Going over the whole floor with 1/2" sub flooring rated plywood will cover all those air gaps and strengthen the whole floor.
So far we have no idea what's there?
Hardwood, 1 X 6's ?
What's the plan for the finished flooring?
Going over the whole floor with 1/2" sub flooring rated plywood will cover all those air gaps and strengthen the whole floor.
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17,847 Posts
I'm in the process of putting back down some oak flooring that originally came with the house.
Originally the oak was nailed to 1x6 planks (sub floor)
In those places where I am putting it back down, I put 3/4" T&G plywood down on top of the existing sub floor...and then the oak.
No squeaks...nice and solid....quieter (you don't hear the thumping as you walk).
Overkill? Maybe...but I'm happy
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2,467 Posts
If you don't have a subfloor, then I expect the walls in your house were installed directly over top of floor boards. That pretty much rules out the possibility of removing the existing boards and relaying them over plywood. That's because there are likely to be nails under the walls holding your floor boards down to your joists. How you can remove those boards under those conditions without dismantling your walls is something I don't know.
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15,055 Posts
Pretty easy. Cut the boards along the wall with a toe kick saw.
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Fine, but then what do you nail your plywood and wood flooring down to along those walls when it comes time to put everything back together?
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15,055 Posts
Depending on the construction, you sister a 2x to the existing joist or install blocking every 16 inches.
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I read the poster as saying the boards are the finish flooring.
Some of the older homes had the finished floor as the only thing across the joists. It was cheaper and a lot of the homes were built with "Barge board". They basically took the barges and dismantled them when they arrived somewhere, then used the lumber to build homes and buildings.
In the OP case, they would have to treat that old floor as a Sub Floor, if they wish to make it not having to deal with using rope for closing the joints.
There are some that love the old floors and the look that they give. But if you have a crawl space or earth directly beneath, you know that you are best to use Tar Paper or plywood to help place the new flooring over. You would still have to seal the gaps before placing the new sub-floor material over the old flooring.
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10,531 Posts
Ayuh,.... My rental house is a 100 year old cottage,....
I ripped up all the junk floorin', 'n refinished the sub-floor boards as the new floor,....
Been 10 years now, still lookin' Good,...
twsager could do as I've done,....
Go below, 'n find the reason ya got a soft spot, if the board is missin' the joist, block it up with whatever ya got,...
I spent a couple of weeks cleanin' the cracks, seams, 'n knotholes, fillin' 'em all with black caulkin',...
4 cases I think,...
Then I rented a floor sander, 'n sanded it out, followed that with a few coats of floor poly,....
It's been hand sanded, cleaned, 'n re-varnished once in 10 years,...
'bout 5 or 6 years ago, I did staple up hydronic radiant heat under it,...
Because of the in-floor heat, it needs re-caulkin' again, 'n of course resandin', 'n varnishin',....
A small price to pay for the joy of in-floor hydronic heat,...
Nice heat transfer too,....
Thinkin' 'bout tryin' a clear epoxy, rather than poly,......
just scared of what long term sunlight is gonna do to it,...
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