Garage settlement?

[Ralph Schade]

Todays house was 20 yr old rural property. The attached garage faced north and the SW corner of the floor had sunken. Also there was a severe vertical crack in the SW corner. Two minor vertical cracks in the west wall and two moderate cracks in the floor. I didn't see any issues with the framing. Although it's been raining for a week here, the water table appeared to be relatively high. I'd just like to pick everyone's brains for comments. In my report I recommended that a structural engineer look at it.

[Nick Ostrowski]

Pics are really small. Hard to make out anything.

[Ralph Schade]

I know, I'm not sure how to make them bigger.:confused:

[Garry Sorrells]

Was the foundation walls precast or pored?

Was the SW crack a straight vertical crack?
How far from the SW outside corner was it

Was the West wall 2 cracks also straight vertical cracks?

How much had the floor sunken?

[Ralph Schade]

The walls were poured, the cracks and the west wall were vertical, the SW crack was vertical directly in the corner and floor has sunken 3-4"

[Ralph Schade]

Sorry, "at" the west wall.....

[Bob Knauff]

Using the camper trailer for scale in the photo, the garage floor must be at least 4' above grade at that corner. Improper back fill behind that tall of a poured wall can cause problems. Lack of proper re-bar or re-bar placement can be a problem with a wall that high too. Also, some places require the footings to be beefed up if the wall extends more than a certain distance above grade.

There appears to be a downspout on the garage wall in the same photo. Where does it empty to? Could the roof runoff be causing earth settlement at that point? How about freeze/thaw problems?

[John Kogel]

I know, I'm not sure how to make them bigger.640X480 is a good size to use.

What Bob said, poor prep before they poured the concrete. Usually, the floor is poured later, so the floor will move independently of the perimeter wall. So I don't worry about floor cracks if the building is straight. The floor can be leveled after settling stops.
Whenever I see foundation movement around here, it is usually related to poor prep and/or poor drainage. You have the added problem of frost heave in Ontario, foundations too shallow. Cracks in the corner shouldn't happen if the builders laid a proper footing. OTOH, it is just a garage in the country.

[Ralph Schade]

Actually, I was more concerned about the possiblility of water washing out the soil under that corner. The driveway and the NW side had depressions as well. I'm not sure where the downspout drains to either.

[Ralph Schade]

Just to follow up, a structural engineer went out to house and examined the settlement. The vendor (not present during my inspection) indicated that indeed water had washed out the soil in that corner under the garage. They redirected the water (I'm assuming the downspout) to a swale. This happened 10 yrs ago. The PEng did not anticipate any further movement and suggested crack maintenance only and if desired, to raise the floor to eliminate the drop.
Thanks for your comments guys!:)

[Garry Sorrells]

I would wonder if the wall was a continuous pour, since the stress fracture showed up at the corners and vertical. The size of gap of the crack, level and plumb of the walls is key to concern of wall and footer.

Wild thought is that one wall footer was not poured on undisturbed earth allowing the wall to settle (stress) evenly at the corner.

Floor drop of 3 to 4 inches begs the question of how fast does it drop over what portion of the floor. I would agree on lack of compaction prior to poring floor. Solution may be as simple as concrete jacking to raise corner. Unless the floor was just not screated and floated out correctly. Then its a pour to fill followed by a floor leveling pour to level it out. Fist much more costly than latter.