Sinking floor and wall

[jay156]

Hi, I looked at this masonry garage yesterday and the back door was way out of square. Looking at the garage floor, one side has settled approximately 3/4". The pavement outside the door is the same. Looking at the masonry above the door, I saw two parallel diagonal cracks, which looked to indicate that the one side of the door has settled while the other one hasn't.

My first thought was that the wall to the right of the door was settling, but the house is about 70 years old, and when I went to the basement, I did see a little diagonal cracking at one end of the wall, indicating some settlement, but it didn't look like enough to cause such a big movement upstairs.

The lady who owns the home told me she had the garage floor replaced about 5 years ago, and a drain pipe put in below it, and that's when the problem started. Could the settlement of the floor cause the wall to go like that, even though it's not really tied into the wall? Could there be another cause? I suspected that the wall next to the floor was settling and causing the floor movement, but it doesn't look like it, and there was no problem until the floor was replaced.

I attached a picture of the door. You can see that the floor has settled on the right and caused a crack between the doorjambs. More pictures coming.

Thanks

 

[BAretired]

Can't say that, Mike but sunshine on my shoulders makes me happy...sunshine almost always makes me high.

BA

 

[jay156]

I don't think this is due to heaving, only for the reason that at the front of the garage (north on my plan), the top of the garage slab and the top of the driveway are flush on the east side of the garage. On the west, near the wall we think is settling, the garage floor slopes down leaving the driveway sticking up about 3/4". (See attached sketch). So I'm pretty sure it's settling (though I suppose the driveway could have heaved exactly the same amount at the east end, but it's not cracked). The only unknown is whether it's just the floor settling, or the entire foundation wall.

It doesn't seem likely that just the floor settling would cause the door to be that out of square. I think it pretty much has to be the foundation, though I don't know what could have caused it to suddenly start settling, unless that pipe they put in, (probably 6 feet higher than the footer), somehow caused the earth 6 feet below it to weaken. That doesn't seem likely either, so I'm kinda lost.

Any ideas?

 

[Ron]

At first glance, I agreed with JAE's premise, but then started looking further. I still think JAE is correct; however, I think the door issue has a different source. Also, the gutter slope does not follow the brick slope, so that's a bit of an optical influence supporting the settlement on the far right looking from the exterior.

If you look at the inside picture of the door, you see a masonry header that has been installed since the original masonry was done. This header is much newer.

The right end of the header corresponds to the exterior cracking. There is also sealant installed in the joint here that seems to match the sealant from the exterior.

The door is binding on the latch side, just below the header. If you look at the crack on the outside, it would appear that the brick over the door on the crack side is lifting upward as JAE described the fulcrum effect. That's not consistent with what's happening on the inside. If the fulcrum were in action, the right side of the door, looking from the inside, would have a gap, not a binding condition.

Looking at the slab crack, it appears to be relatively minor and likely a restraint condition, not settlement.

I suspect that the installed head is not properly supported and bears on the door frame. Notice the other side of the header has a half-block support, while on the cracked side, it appears to bear on brick and the door frame.

 

[JAE]

I don't know if I'm correct or not - really would need to study the horizontal elevations of the foundation walls, brick course lines, etc. to know what went up and what went down.

 

[jay156]

Thanks Ron, I think though that more than just the header is moving, because while there is a binding condition at the top of the door, there's also a gap through which you can see daylight at the bottom of the door on the latch side. It appears that entire end of the wall is moving.

 

[msquared48]

Jay:

You really need to see what the top plate is doing elevation-wise. Can you make a plan of the garage and take a few shots on the top plate elevation and post the results?

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask