Want to replace wood floors but don't have a subfloor. Do I need one?

HI group,
I bought a house built in 1925 which has oak floors. They are not in the best shape, with cracks and weak spots (funny the home inspection didnt really call it out as a problem). Additionally, it has been refinished as many times as it can take so we are going to replace it. There is no subfloor, however. My question is: could you have the new floor installed right on top of the old floor (making it become the subfloor) or would you just have both installed brand new? Or just a new floor without a subfloor?
This is for two rooms on the ground floor that is over a basement. Currently we hear the boiler and see through cracks, so I'd like something very sound and as sealed as possible. Not married to any particular type of wood so if one type is better I'd love to hear about that too.
Thanks in advance to this very generous group!
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On 2/9/2009 5:21 PM Dairy Godmother spake thus:

What do you mean, "as many timea as it can take"? Are the floorboards too thin? Sounds as if you just don't want that old floor anymore. Floorboards can "take" an arbitrary number of refinishings. They don't wear out.

Are you sure? You say you can see through cracks in the floor, so this may be the case, but it sounds weird. Houses have been built with subfloors since forever.

If the existing floor is structurally sound and reasonably flat, then you can use it as a subfloor.

Nope.
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My house was built in 1916 and there is no subfloors.
We got to the point where we thought another sanding and we'd be in the basement. Probably wouldn't happen, but that floor had way too many bad spots. I would never be able to run and skate across in my socks.
We just put a new wood floor on top of it and all's been well so far.
BR
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Thanks, BR. My situation exactly. There is definitely no subfloor, and it visually does not need refinishing -- we'd love to keep it but seemes silly to try and reinforce it and fill it from below. And would love to go sock skating too -- have a new baby and just cant imagine the little guy cruising around the old floor with splinters, ets.
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sounds good
mk5000
"you can be all you want in front of me you can pout you can smile you don't have to be perfect "--robin thicke, you;re my baby
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Dairy Godmother wrote:

Consider laminate flooring with a sound dampening underlayment. It can be easily installed over your existing floor. Squeaks and "mushiness" should, of course, be dealt with while you can access both sides of the floor.
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HeyBub wrote:

Laminate is UGLY, doubly so in an older house- it just looks WRONG. Can't say for sure without seeing it, but old floor would probably work fine as a subfloor. Fix the squeaks and any mushy spots, and shop around for a deal on real hardwood, preferably something narrow to fit with the age of the house. I find it hard to believe there is NO subfloor, unless the place had an abandoned remodel. House of that vintage would usually have 1x4 or 1x6 plank, nailed at 45 degrees to the joists. OP, where are you? There were different practices in different areas.
-- aem sends...
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Most old houses with oak floors have subfloors; usually 1x4 at 45 deg.........
but all vintages of houses were built w/o subfloors.
My house (1930) has oak flooring & 1x4 subfloor but my next door neighbor's house (1952) has oak flooring and NO subfloor. It is currently owned by the son of the original owner...so no remodel.
One issue with using the old floor as the subfloor.....not at 45 to the joists (which is a minor nit)
OP- depends on your budget.....
either use the old floor as a subfloor or
remove old floor, add new subfloor (plywood not OSB) and install a real wood floor.....laminate sucks.
A thicker (3/4") solid wood floor would most likely be way cheaper than the second option of adding a subfloor.
You bought a period, "charm" home, don't put in laminate and ruin the look.
A new floor w/o a subfloor would be a bad idea, why tear up the old would floor & not replace it...either use it as a subfloor or tear up and install a proper subfloor.
I wonder how the floor installer handled the wall / floor interface condition? Wood floor goes under wall sills?
cheers Bob
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The builder laid down the floor boards over the open joists, then built the walls on top just like any other construction of the time.
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On Feb 10, 6:02am, snipped-for-privacy@rochester.rr.com wrote:

That's what I figured but he "forgot" the 45 deg 1x4 subfloor, an important feature in raised foundation homes....I wonder what else he skimped on?
cheers Bob
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wrote:

What does the 45 degree mean? (I understand 1x4). Inquiring but ignorant mind wants to know...<g>
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On 2/11/2009 1:28 AM snipped-for-privacy@nospam.com spake thus:

>

Subfloors are often (not always) laid diagonally with respect to the joists, at a 45 angle.
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On Wed, 11 Feb 2009 11:01:02 -0800, David Nebenzahl

Oh! (hits self on head) I was thinking 45 degrees VERTICAL! Isn't that pitiful <g>
Thanks. Now I can sleep o'nights.
Amiga
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i dont like laminate either - though it technicaaly would solve the problem. there is definitely no subfloor. we are in stamford, ct and its a 2-story bungalow-type (thats what we would have called it in california - i assume same here). it seems bizarre to me to be walking on hardwood floor planks with cracks to the basement. i think in summer when we bought it the cracks werent as apparent due to more moistue. and like i said the inspector didnt call out any structural problem i just dont trust it long-term now that i've lived here for 8 months and have a baby jusy jonesing to crawl in 3-4 months.
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You have a miriad of choices if your floor joists are sturdy. if they aren't, you MUST shore them up to the point they ARE sturdy by either adding more joists nest to them, or a beam under them.
Assuming your floor joists are sturdy, you can replace the boards that are weak and mushy if you can get the proper height (thickness). Then you can decide what floor covering you want.
Once you decide whether it is going to be carpet, laminate, tile or whatever, then you can decide what is best for a sub-floor. When deciding, take in consideration of the height of the thresholds and the transitions you'll need to make.
Hank
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I'm pretty sure the OP is considering a new wood floor...tile, laminate & carpet doesn't seem like what she would choose considering the type of house she bought.
cheers Bob
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Get a pro out to tell you if it has been resanded to many times a bid a fix of issues. But it probably hasnt been sanded to thin. If joists are weak, sister on another one, if a few planks are week I braced mine underneath with plywood. Old floors were thick, mine are 3/4 oak with no subfloor and can take many sandings. You can go over the old one but you will save thousands by keeping what you have. A weak plank may have a hidden knot underneath, so support it from underneath. A good sanding and 3-6 coats, a few repairs, and it will be great.
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a contractor i trust said they are too thin, and though i obviosly dont know about these things, my gut agrees.
If joists are weak, sister on another one, if a few planks are week I braced

thats what DH has been doing - i think the joists are fine.
Old floors were thick, mine are 3/4 oak

I dont think these were 3/4 - i'm almost sure thinner.
You can go over the old

definitely a thought - we'd rather save money obviously and put it toward the heating system. if we could *confidently* reinforce the planks *and* fill and smooth all cracks i'd be happy keeping old floor. Sounds like not having a subfloor is not a huge deal on its own
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Filling the cracks is problematic for the same reason that they appear/ disappear in winter/summer - the wood expands and contracts with temperature and humidity, which would tend to loosen the crack filler and then it looks worse than when you started. It sounds like the quality solution would be to install a new layer of hardwood over the old. The things I would worry about with that are (1) having to re-do doors, doorjambs, baseboard, etc. because of the new thickness being added, (2) whether there is a problem driving the flooring nails through that old oak - I assume a pro would just be able to set his airgun up a notch or two for that (3) whether flaws in the old flooring would telegraph through to the new - if there is any unevenness. Especially since you would be installing the new floorboards parallel to the old (perpendicular to the joists). You might want to discuss these with prospective installers and ask for references from past customers that had the exact same situation. (I've never seen a place with no subfloor except in a beach house, but it may be more common in your area.) It won't be cheap but it will be permanent and will add value to the home. Some people do install hardwood flooring as a DIY project to save money, but it's pretty ambitious. -- H
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That'd work... Just stretch the carpet across the open joists. It'll be fine.
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