Sub Floor

Tim M · Thu Mar 13, 2008 1:44 pm

It's been awhile since I came to all of you for help. But this has me perplexed. I noticed a crack forming in the floor in front of my front door, running across the room. The crack over time has gotten wider. The vynyl has cracked. Looking into the crack it is where one sheet of subfloor meets the other. The problem is the floor joist isnt under the edge of bloth sheets. One panel, sits right to the edge of the joist and the other sheet seems to have another joist about 1 inch in. Not sure why there are 2 seperate joists here, but they seem to be pulling away from each other. There is a heat register in the vicinity also. Any ideas of whats going on? Thanks for your help in the past.

Greg · Thu Mar 13, 2008 4:34 pm

Tim, It sounds like you may need to do some "exploritory surgery" to find out what is going on. Have you checked under the home for any problems? You may need to sister up the joist to give the edge of the plywood support. Greg

Tim M · Fri Mar 14, 2008 9:50 am

Thanks Greg...I'm not able to see anything from the underside with out tearing open the belly wrap. There is another 'squeek' on the same floor. I have been toying with the idea of pulling the floor up to see whats going on down there. I'd also like to check the duct work at the same time. Make sure thing are together. Do you think attaching another joist to the existing would be a propper fix ?

Brenda (OH) · Fri Mar 14, 2008 1:02 pm

Hi Tim,

I understand that tendency to want to do the repair from above if possible, if the belly is in good shape. It can be easier to go from below the MH, so it is a coin toss on whether you want to cut your floors, or your belly wrap. it is warmer and more light from above though, LOL!

I found in repairing old floors, that if I could not get the patch edges to end on a joist, I could make it more sturdy by cutting out the bad spot, installing a 2 x4 section onto the underside of the flooring that remained. the 2x4 was attached, by screwing down from the subfloor above.

So the 2 x4 is attached to the floor, and 1/2 of its width extends into the empty space, the oher half is under the remaining subfloor. the floor patch then catches/lays on the 2x4, instead of being free moving. and of course, you can screw into the 2/4 to prevent it moving side to side or up and down as much as it is doing now.

So basically, the entire space I was replacing the flooring in is outlined by a square either by having part of the floor joist as the rim, or by putting pieces of 2 x4 between the joists, or by putting a piece onto the edge of the remaining floor if the patch ends between the joists.

i can say that I am having some success doing this, the floors go from bouncing to solid in the areas I fixed. Of course, some of the improvement is going from 3/4 inch particle board to 3/4 inch plywood, much less flex!

hope this helps. I am a visual person, trying to write this clearly is a stretch of my composing skills.....

Brenda (OH)

Greg · Fri Mar 14, 2008 3:50 pm

Brenda is correct. it is a coin toss unless you know for sure the subfloor is bad. You can screw a 2x into the joist as I said to give support to the edge. you can also add a 2x between 2 joists for support if needed. I have found it is much easier to use screws unless you have a framing nailer. Greg

JD · Fri Mar 14, 2008 6:12 pm

I have suffered through a lot of floor repairs. Trying to get blocking in real tight under part of a floor can be a pain. You are trying to hold things tight with one hand and drive a screw or nail with the other, all while standing on your head or in some contorted position. I have used Passlode airless, pneumatics, cordless drills and hammers. Many times none of the power tools will get in there. But I recently bought a Bostitch Palm Nailer. OH! I am sooo mad when I think of all the black thumbs, slipped screws where I run the screw gun into my hand, holding some heavy nail gun for five minutes trying to find just the right angle and push to get the dang thing to fire.

The palm nailer is a dream. You just load a nail into the tip (magnetic) and push it against the board you are nailing and rat tat tat, nail is in there right now. Lightweight, small and cheap as nail guns go. It comes with attachments for finish nails and hangers, though I doubt that I will use it for anything else. I have nail guns for subflooring, framing, fences etc., so I would use those guns when I can.

JD

Brenda (OH) · Fri Mar 14, 2008 9:34 pm

Ooh... I see one of the next tools/toys I'll be pricing!

Brenda (OH)

Tim M · Sat Mar 15, 2008 12:29 am

You all have excellant tips. My subfloor is in good shape, other than pulling away from each other. Its not rotten or anything. And I have seen the palm nailers advertised somewhere. Sounds like a great Fathers Day gift! hmmm... I'm not as agile as I use to be. Crawling on the ground under my mobile home has no apeal to me at all.

I'm kind of comfort driven these days. I think I will still try pulling the floor up and see whats going on. Does anyone have any idea what would have caused this? You think it might be a manufacturing flaw? I did notice a staple thru the crack. I assume the floor was maybe glued and stapled. Not exactly quality work. Thank you all for your help and advice.