Subfloor slopes downward from exterior wall for 2-3ft then levels off...

Hi Folks,

I recently removed all carpets, laminate, etc. in my 35 year old house to expose the subfloor and prepare the house to install hardwood flooring. Along one of my exterior walls, there is a noticeable downward slope away from the wall that extends 2-3 feet (i.e. the width of one sheet of the plywood subfloor). This slope extends across the entire wall of the house. I went to the basement to investigate, and it looks like the main support beam, which is completely level across the entire house, that sits on top of the foundation has settled over time. The reason I assume it has settled is that there is a small gap above the main beam in the concrete foundation where the beam rests. The supporting beam is perpendicular and to the wall in question, and directly in the middle. It seems like the floor joist that is sitting on the foundation has stayed in the same place over time while the rest of the house sunk. It looks, from looking below, like the last two floor joists from the wall have been pulled off the main support beam and are still connected to the subfloor. There is a small gap between the last two floor joists and the main support beam (not including the joist sitting on the foundation). The gap is approximately 1/4" under the first joist off the foundation wall, and 1/8" under the second joist, which explains the slope above. Can I fix this issue without having the raise the main support beam across the entire house? My first reaction was to pull the last sheet of subfloor from the wall and shave the joists to level them, but the gap between the joists and the main beam leaves me to wonder if this is the most important issue that needs to be addressed instead.

Thanks in advance!

Welcome Andersp:
I would need some pictures of this one to give you any sound advice. It sounds like some posts in the basement didn't have any footer under them, which allowed them to sink. Is the basement floor cracked? You may need to cut square holes in the basemet floor, dig down to bearing soil with post hole diggers and place some new concrete to hold the house up. Then jack it and wedge or space it up until the whole floor is level.
Please post some pictures to give us a more detailed look.
Glenn

I read this earlier but really had a hard time piecing it together. Definately some pics woud be helpful. If you have a hard time uploading them here, you may want to try PhotoBucket.com, then provide us a link or use the image button when you write your post. Sorry I can't be of much help. What Glenn says about the posts sinking makes the most sense, but then it seems like it would be a gradual slope to the center of the house. However, this you describe seems like something is catching the subfloor at the outside edge, preventing it from sinking with the rest. Some photos of the floor, the basement, and even the outside of the house, may help us spot the problem.

Thanks a lot for taking the time to read my post. I did some research, and I am very confident that I have the same problem as the attached picture/article. If I were to cut the subfloor in the middle of the first joist (the joist that has a 1/4" gap underneath it between the joist and the main beam) from the foundation wall, I would be making a cut approximately 2-3" from the wall upstairs. So, if this is the solution, and the floor drops back down, I will also need advice on how to address the final 2-3" of subfloor that will end up being higher than the rest of the floor once the joist drops back onto the main beam. I assume I would just cut it out and install a new subfloor using braces since it's only a few inches, an no one would really ever walk along the edge of that wall.

Thanks again!

Way to Go, Andersp!

If that's not the issue, then it's got to be something along that track. As for cutting it, I'd get up close to the wall with a reciprocating saw (SawZall) and just cut enough to let it drop back down to the joist. The nails will probably still hold it up, but a whack with the hammer will fix that. Then I'd put in a few more nails or screws, seeing how the original nails have now been disturbed. Wouldn't want to get a squeeky floor.

If you have to cut it 2 or 3 inches away, you can fill the remaining space with 1x lumber (which is actually 3/4" thick), as it would be more ridgid than a narrow strip of plywood.

Thanks Tool Guy! I'm pretty sure that is the issue as the main beam is perfectly level across the house. What happens if the joist doesn't drop after cutting it? For example, could the joist "warp" into that permanent position over time? If it doesn't drop, how could I pull the joist back down to the main beam and keep it there?

Thanks again!

The joist?

Okay, we really need some pictures.

I see the joist is down to the 'settled' level, while the plywood subfloor is lifted away from it because of being snagged on the sill plate. Is there a gap between the joist and the subfloor, as shown in the drawing? Just trying to get a clear picture here.

Sorry, my camera is out of commission However, the gap is not between the plywood and the joist, it is between the joist and the main beam that would normally support its weight. The subfloor is screwed to the joist, so the subfloor still rests on the joist nice and flush with no gap. Therefore, it looks as if the subfloor pulled the joist off the main beam.

Does this make sense? I could draw a picture with Paint if you still need a better understanding.

Thanks.

I get it now. So, the joist is bent. To be honest, I don't know if it will unbend. It might drop and leave a dip in the floor.

What I'm wonder is why the joists bent. I mean, since the joists are to span the distance between the foundation wall and the main beam, it seems it would be an even slope the whole distance.

Well, you are close in your drawing, but the joists run parallel with the wall in question. So, you have the main beam that runs directly into the middle, perpendicular to this wall, and the joist running parallel with this wall and sitting on the main beam. Where the two joists (one for each side of the wall) meet in the middle over the main beam, there is a 1/4" gap under each one.

Does that make sense?

Another catch is that I have a bedroom wall upstairs that runs directly over the beam. So, I'm not sure how to make the cut in the floor so that it releases from the wall and drops because I assume the wall goes over the foundation since it might be a load bearing wall? I'm going to another computer to upload a picture that I took with someone elses camera. Wait until the next post...

Ok, here's some real life pictures. First one is a shot from the basement, and you can see the gap underneath the last joist before the wall, and there's even a tiny gap under the 2nd last joist. The 3rd joist from the wall is sitting on the beam. The second picture if from upstairs in the same spot right above where I took the first picture. You can see the bedroom wall on the right that I mentioned above, and if you look in the bottom right corner of the picture, you can see the gap underneath the drywall, and it gradually disappears as you move along the wall towards the green wall. This indicates the slope.

Hope this clears it up...

Hello Andersp:
I think I am seeing a double 2 X 12 beam with floor joists crossing over it and meeting joists coming from the other way. Perhaps the joist coming from the other side is on the beam and the ones on this side are held up to make them match on the top. The crack under the drywall is normal; you'll see that in a lot of houses.
Let's give the floor a marble test; got a marble? Lay it down by the green wall and see if it moves and in which direction. As an appraiser, I used to drop a pencil and see if it would roll. That was in a strong coal mining community and many houses sunk a foot on one end or on the backside as the old works under them fell in. Lay the marble in several places, stretch a string from wall to wall and measure under the string to the flooor.
Sorry, I just don't see that much of a problem here.
Glenn

You are right, there is a joist for one half of the wall, and another joist for the other half, both meeting up in the middle over top of the main support beam. Both joists are completely lifted up off the main support beam, and still attached to the subfloor. The slope is steep enough to the point that I could not install hardwood over it. The pencil would probably beat the marble in a race The slope isn't too bad in the corners of the house along that wall, but a foot or two from the corner is when the slope really kicks in and consistently gets worse toward the middle of the wall (i.e. directly over the main support beam). I assume the corners are unaffected because the joists are embedded in the concrete foundation.

Your thoughts?

Thanks again!

Your problem is typical of most homes. The wood shrinks and we end up with settled floors, cracked tape joints and gaps everywhere.
What to do? You could go around and jack things up here and there, then fix all the sheetrock cracks and such. Or leave it be and call it character in the home.
The nails are still holding the joists up at the beam, they wont move without some serious banging of the floor. The wood joists which have bends will also most likely stay bent. This is called "wood creap"( what did you call me)
This to me looks like my house when I purchaced it. I went around and jacked things and shimmed them where it was possible. I broke some sheetrock and replaced it and painted. Now I have floors which do not bend to the center as much. It takes alot of work ,but doing it gradually is OK too.
Just make sure you do not change any pipe drains so they are going the wrong way.
I used a lazer level in the basement to check my hieghts. The problem was my foundation was a half inch out of level, so I split the difference.
Have fun.

Well, I would love to be able to leave it, but the slope is so steep for 2-3 feet from the wall that I will have to do something with it because I can't install the hardwoods with huge gaps underneath.

I have one other issue that I discovered at the other end of the house. There is one joist that seems to be pushing up where two subfloor sheets meet. Looking from below, all looks normal. So, I'm assuming that I can remove/replace area with new subfloor and shave joist a bit if required to level it off?

Thanks again.

I would start with jacking things slowly and se where it goes from there. You may also be able to cut the nails at that joist and bring it down with jsut a few jumps or hits with a large hammer.
If that does not work then remove subfloor and have a straightedge to see how much to remove.
Just jacking that beam in the pocket looks like it will help. Just do not use wood to support underneath, it will just compress again. Use steel.
Good luck, we love more pictures too.

Well, for my hump at the other side of the house, I read that I could just take a floor grinder/sander to it to level things off and make sure the nails/screws are below the surface enough so that they do not interfere.

As for the slope along the exterior wall, I'm thinking that I want to make a cut in the middle of the last joist before the foundation to start. See if I'm able to lower the joist back onto the main support beam once the floor is "released". If the joist is stubborn and won't lower, than I guess I can shim it underneath to fill in the gap to support it, and just shave the last two joists a bit and replace the subfloor at a level position.

Any reason why this should not work?

Thanks again.

Well, It is like I stated before. I would jack things up to the highest point possible in the areas which need it. Things settle down, they hardly ever lift up. The one joist which has lifted may look that way because everything else has fallen. I just hate to cut things when you have other alternatives. I know it is easier to just cut a joist but that is your call You could end up chasing this issue around when all you had to do was a little extra work to begin with. Don't forget in the areas you can not get perfect you can also use a self leveling floor mastic, kind of like concrete. Now these are only my opinions from what I can see and what you have explained. More pictures with levels on the floor or a straight object with contrasting color can help to understand more. Also you can call in a contractor to get their opinion and see if there is something we are all missing.
Let us know...

Thanks everyone for your help. After hearing what everyone has been saying, and talking to a guy who's been building houses for over 30 years, I have determined to make the adjustments at the beam. The main beam below the sloped area has definitely settled at the point where it rests on the foundation because there's a small gap above it. I will try to jack it back to it's original height and shim it underneath with metal shims. This should bring the beam back up to the joists so that the joists can lay on the beam once again. If other adjustments are required afterwards with the teleposts across the house, so be it.

Thanks again.

Sounds like you found someone who will help you out. That's great. Let us know what else we can help with and keep us in the loop. We would love to know how it turns out and any pointers you can give to others.