Floor Joist Raising

[Del]

Hi, I'm new here, but a search didn't seem to turn up my exact problem. It is similar to the RN having the releveling question, perhaps, but not the same.

The mobile home in question is a 1997 double-wide. Tampa, FL. My step-daughter lives there, and last week she told me there is a bulge in the floor in the bathroom. I went and looked, and it appears that the floor joist is trying to push through the floor. This is running perpendicular to the marriage line, so it's not the beam, but rather a joist on top of the beam, I guess.

There doesn't seem to be any moisture leaking, that I can detect anyway. The floor is not soft, it is just raising in this spot. About 3 feet from the "marriage line". It has raised far enough that the laminate floor in the hall outside the bathroom is lifting too.

I crawled underneath, expecting to perhaps find that a pier had sunk or something like that, but everything underneath appears to be okay as far as I can tell. Nothing obvious.

At this point I'm contemplating either taking a skilsaw and cut a hole in the floor, or a knife and cut a hole in the bottom membrane, to see what's really happening. But getting at the bottom is really tough as there are A/C ducts under there pretty much right in the way. Plus holes in the membrane might be harder to fix than holes in the floor.

Suggestions?

[altasnowman]

Hi Del and welcome to the site.
From what you are describing it sounds like the floor is de-laminating and if that is the case it may be a pinhole water leak problem.if you can, check to see if the water lines run in relation to the swelling. if you find that water lines do run in that area check to see if you have a pinhole leak (to do this you will need a bright light , shine light down the water lines and look from behind the light if it is a pinhole leak it will look like steam in the light beam.) Hope this helps.

[Del]

Thanks, I'm not sure if I described it accurately. I don't think the MDF or plywood is delaminating, you can physically see the outline of the joist (2x6 or 2x4) pushing up on the linoleum.

I'm guessing that the joists are not continuous, but rather two 2 x 6s may have been laid side by side and nailed or fastened together. I'm theorizing that the two portions of joist have become separated from each other.

I guess a pinhole leak is possible, but if so it would be inside the floor, so either way I would still need to open the floor either from above or below. I did push on the membrane below the area and was unable to detect any standing water there.

[altasnowman]

Hi again Del
If possiable check from underside of trailer. doing it this way you don't create further damage inside and tho it will be cramped and a tight area to work in going from underside is better. let us know what you find.

[Yanita]

Just a thought, seen this many times as well....by chance is there a ac/heat duct running in the same area. Sometimes these will condensate and cause floor swelling? Just a thought. What type of duct work does this home have, flexible duct or metal. Ductwork is typically up between the joist, except for cross over pieces on multisectional homes.

Oh yeah, welcome to the site...

Yanita

[Del]

Thanks, Yanita. I believe it has mainly flexible ducting, there are some large flexible tubes (14" - 16") laying on the ground under the mobile home wrapped in insulation. However, there could still be non-flexible ducting up inside the floor joists as well ...

I don't recall if there is a cooling duct in the immediate vicinity of the swelling, but that's a good possibility. A couple of years ago the A/C unit had sunk on one side and a began draining into the ducts. A large quantity of water got into the ducts. We jacked the A/C unit back level and drained the water out of the flexible ducts, but there could be more in there by now, I'm not sure.

[Robert]

Hi,

Those flex ducts need to be up off the ground. If they are crossover ducts (most likely), it is best to either have hard metal across between two 90* elbows.

Or, have the two 90* ells and stretch the flex duct tight between them.


This keeps off the ground and stops kinks and blockages, plus better protects the flex from rodents and ground rot.


If your main trunkline(s) are having excessive condensation, you most likely have openings in the belly wrap.

Be sure the underbelly is sealed tight with good insulation to prevent the condensation problems.


Take care and best wishes,
Robert

[Greg]

Del, The bottom line is that you need to get a good look at what is really going on, either from the top or the bottom. You may be able to peek in through a heat duct by removing the staples and dropping the duct down if you ge really lucky. I also would suspect a moisture problem if you have partical board subfloors is is very likely that they have swollen. If so replace with plywood. Greg

[Del]

Thanks for all your suggestions ... you guys are great.

It appears after taking your advice and cutting the belly wrap to look , the joists are unaffected (thank goodness). However what I now theorize is that the leak is behind the wall in the shower. The water pipes under the floor leading to the shower are not wet to the touch, so that leads me to believe the leak is in the wall.

The floor is visibly wet under the tub and therefore the floor which is MDF has swollen and lifted. What looked like the edge of a joist I guess was just the edge of a sheet of MDF.

Next step? I guess pull the surround off the tub and open the wall, see if I can spot the leak and then fix it. Then ... repair the floor ... and the wall.

As I said, this shower hasn't been used in more than 2 years so it isn't a dirty water leak.

Any suggestions from those who have been there? I'm planning to buy Mark's book before I tackle it. How concerned do I need to be about mold getting into the living quarters (beyond what is already there of course).

[Harry]

Hi

I'm about 100 miles north of Tampa.

Looks like you have the beginnings of a bathroom remodel.

I would remove the surround and all wall panels, fix the leak and dry it all out good with a large fan. If you see mold spray it with 50/50 bleach and water then wipe it off. A lot a mold is not good but if you live in Florida mold is a reality.

Upgrades include plywood flooring, pex water pipe, install water cutoffs, better plumbing fixtures, an access panel.

Good Luck

Harry

[Greg]

It looks to me like you will be learning all about subfloor replacement. Not a hard job, but it is time consuming. Greg

[altasnowman]

Hi Del,
Boy do those pics look familiar LOL cause my neighbours floor and underside look like that too. only difference is yours has black mold. guess you are going to learn how to do a sub floor and bathroom. Best of luck to you and keep pics coming. OH ya to keep mold from entering rest of home take a sheet of plastic and tape it over doorway after you enter the bathroom.