I purchased a home built in 78 that has homasote subfloor. I had an inspection and this was not caught. The subfloor is sagging in between the joists but the joists are pretty much level.
My question is would it be an option to put 3/4 plywood or OSB on top of the Homasote? Essentially creating a new subfloor?
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Replies
When you say "on top" do you mean under the Homosote? If so you could certainly do so but the problem is only cosmetic. The Homosote never provided any structure to the floor and was probably installed to reduce sound transmission.
I mean the homasote is used as the subfloor. There is nothing under. I am asking if I could put a new subfloor on top without ripping the homasote up
Are you sure you mean there’s Homasote as a subfloor directly fastened to the joists?
100% that’s what I mean... unfortunately
What is the benefit of going over the Homasote? Why wouldn't you just remove it before adding the new?
Time. Removing the subfloor is a lot more work than just laying subfloor thickness plywood on top gluing and screwing it and moving on.
Gluing? You're going to glue it to the homasote? What's that accomplish?
What's on top of the Homosote? You've got Homosote, then what, then flooring of some sort?
Homasote then just the flooring.
What kind of flooring?
If you have full 3/4" wood flooring you aren't going to fall through but I agree that is inadequate. I think I would be cutting 3/4" plywood and nailing it between the joist from the bottom. I'd use 1 X 2" s on the edges to push it up tight. I've done this to rooms but never a whole house. Worked fine and years later the tile on top is still not cracked.
I am just as confused as everyone else here. I have seen homasote used on walls but never as a subfloor.
What type of flooring is on top of this? It seems you are removing this flooring and keeping the subfloor to save time?? Sounds like a long-cut to me.
How do you plan on removing that flooring without disturbing the homasote?
Pictures please.
So the layers of my floor are from top down.
Laminate(run parallel with joists), padded underlayment, patches of linoleum, then Homasote attaches to the floor joists.
My thought was to remove everything off the homasote and put 3/4 ply on top of it secured to the floor joists through the This would save me the time of ripping up the homasote while giving me the strength of the 3/4 ply
I think you already know the right answer but you are looking for the forum to allow you the shortcut. You aren't really saving much time trying to put the subfloor ontop. The Homasote will be just as easy to remove as the laminate and linoleum. Take it down to the floor joists then glue and screw plywood down.
If you werent removing the flooring I would go with what Florida suggested but it's a ton of work.
Yes Florida sure for a patch around someone else’s butcher job with the 1x2. But doing and entire room with tile! Or an entire house!?!?
Maybe I should define “long-cut” for you. When you approach a task and know the right job but choose a cheaper/easier method you know is wrong.
Isn’t this your house?
Maybe I should have been more clear for inexperienced users.
What I said was to cut plywood to fit between the joist, run 1 x 2"s down the edges to force the plywood to the Homosote and nail them in place. That's a very acceptable repair in some situations. It is a big job but not nearly as big as removing all the house flooring, trim, cabinets, etc and installing plywood from the top.
Now that we have more information about this floor I might do things differently and go from the top down. I might also consider just going over what's there but I'd want to see the conditions first.
Whether you remove the homasote or not, you still need blocking at the edges of the walls that sit on the subfloor. You are probably going to need to remove some homasote to do that. If your plywood is not T&G you will need to block all the edges.
Mike
Florida I see by your response you didn’t realize the flooring was being changed. In that situation sure stiffening the floor is a good idea.
I thought you were saying to remove all the finished flooring, save the homasote, and stiffen the floor from the bottom. That my friend is a long-cut. Again I realize that’s not what you were saying.
To get back to the question. If your committed to removing all the finished flooring I am not sure how saving the homasote is saving any work. In fact I would say it’s easier to cut everything out at once. No peeling, sticky mess.
Florida his original question was to add a subfloor on top. Which then needs a finished flooring of some kind. That means all base moulding, cabinets etc. are changing in some way. I have seen you post often and I don’t disagree with anything I have seen before. But this time you just misunderstood the question so I miss understood your answer.
Seriously ”deefening” is this a pop quiz hot shot. Yes it has been used in bathrooms for quite a while to get the tile flush with the rest of the floors after the mud job. Yes this has its advantages. It also has its disadvantages. In this case it’s way more time and material.
Just because you post often doesn’t make you and expert. Just because I don’t post often doesn’t mean I am not.
I am open to another pop quiz.
Sorry to write a book and to steal the thread.
I think tearing it out and putting a new 1 1/8" plywood / OSB sub-floor in is the way to go. When in doubt, remove the substandard materials.
I have no clue what your last 2 paragraphs mean but I certainly agree that posting a lot doesn't make me anything. It's my 50 years of experience that makes me an expert.