Life span of a subfloor?

Proulx06

I own a split level that was build in 1967. Both upstairs bedrooms, the upstairs hallway, and the living room are old, beat-up hardwood. The hardwood is very loud, and every step either squeaks or cracks throughout the surface. The floor also flexes in several areas, particularly in my toddler son's room (it also squeaks in a 3'x3' area near the door...tough to sneak out after he's fallen asleep).

I'm curious what the lifespan of a subfloor is. Could I just be exceeding it? My wife would like carpet in the bedrooms anyways, so part of me wants to tear up the hardwood, replace the subfloor, and put carpet on top of that. Is that overkill? I think the room may have had carpet at one point, as there is about a 1.5" gap to the bottom of the door.

We've been in this house for about 8 months now, and we're discovering one hack job after another. We've resigned ourselves to just redoing most of the house, and the flooring is part of that. Unfortunately, money is an object, else I'd hire this whole thing out.

Jackofall1

If you decide on carpet, and you pull up the old hardwood, you can do a couple of things, firstly, try screwing the old subfloor down to the joists every 8", this should quiet things down.

If the sub floor is in bad condition, ie, was left in the weather when they initially built, water stains and delaminating are signs if its plywood, you may choose to pull that up to and replace with 3/4" T&G sub flooring, again screwed every 8"-12".

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Proulx06

Thanks, that makes sense. If the subfloor is damaged (and I'm assuming parts of it are, since it flexes heavily under my 190lbs), can I just replace the damaged parts with the same thickness? Or is it required that I replace the entire room? This is a corner room on the second floor of a split, so if I replace the whole room, do I somehow need to join the new subfloor to the outside frame at all? Does the subfloor extend under the outside walls typically?

I've done lots of DIY projects (including tile and laminate installs), but subfloor replacement is brand new to me.

rusty baker

Subfloor typically extends under the outside walls and can be tricky to replace. ON very old houses sometimes the floor was put down after the walls, but I have only seen a couple like that.

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Proulx06

That's what I seem to be reading. I guess I won't know on my house until I remove the hardwood. Assuming it does extend under the outside walls, what is the protocol for replacing it? I'm assuming it has a role in keeping the building structurally sound.

As an aside...I believe there may have been carpeting in the bedrooms at some point due to the door having almost a 1.5" gap underneath it. Since I have a bit of room to play with, would it be an option to re-do the entire room with 3/4" T&G OVER the existing subfloor? Please tell me if that's a ridiculous idea and I'll never mention it again.

Jackofall1

Just replace the parts that you have to replace, with the same material thickness, sometimes the problems with flexing are just limited to sub-floor, you may have a bad joist, they are much more difficult to replace, especially on the second floor with finished ceiling below.

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AllanJ

Subfloors do not wear out. Either they rot or they are abused.

Meanwhile it is not unusual for nails to work loose leading to squeaks. While you are replacing carpet or finish flooring and the subfloor is exposed, you can screw it to the joists to minimize squeaks. Drill a pilot hole through the subfloor so the screw slides easily (but of course not that big down into the joist). You can leave the old hardwood there and screw down through it if its thickness is not going to interfere with the next flooring you put down.

Putting a new smooth layer of thin plywood over the subfloor is extremely common prior to putting down vinyl but is not necessary when putting down new laminate or hardwood or carpet.

Nothing wrong with putting down a new subfloor on top of the existing subfloor and then adding carpet, etc.

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Gary in WA

If you have forced air heat registers, remove one and check if you have real plywood or particleboard (glued sawdust) which may not be T&G. Early '70's I installed that in new houses for tract homes (for General Contractors) which was the norm. Great when new, later weak and sagging from years of moisture. They don't use it today...... This will help you decide.

Gary

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cep89

I'm replacing a subfloor now and it is a very hard job. I had to do the whole area due to previous hack jobs. All of the ideas others have posted are good. What bothers me is the heavy flexing you mentioned, it's possible that one of the previous hack jobs did some damage to the structure. Like cutting a notch in the joists.