sagging outside brick wall 6

[lubos1984]

hello everyone,

I recently did an inspection of a old victorian home in Toronto. While doing the inspection i noticed that the outside brick wall has sagged around the archway windows and in some areas of the wall. Upon closer examination there were no lintels installed in the window arches and I think that contributed to some of the settlement you can see on the pics.
The brick settlement seems to extend above the lintel as well however as you can see from the brickline above the window.

The house is constructed with two rows of brick on the outside wall. I didn't see any settlement at the foundation level although the outside wall seems to have concrete parging.

The client wants to know what the best recommendation is to repair this issue and if there are any underlying structural problems. They are considering a re-work of the outside brick veneer but wanted to know if there are any foundation issues. Any opinion on what some of the causes of the brick settlement may be and what other clues I can look for ?

Thank you!

 

[Tomfh]

r13,

The header courses do not align. The left side is 1 course lower than the right side:

The left side has to have settled, breaking the brickwork between the windows in the process.

 

[r13]

Tomfh,

You could be right. Which will be a nice finding to put on the report. The OP shall check level of the wall.

 

[gte447f]

Tomfh is definitely right about the fact that the left side of the wall has settled 1 course relative to the right side of the wall. It is obvious, because you can see that the header courses on the left and right do not align, and are instead off by 1 course. For those having difficulty following this, I think some may not be familiar with multi-wythe brick construction and what a header course is. The courses of "half" bricks that you see every 10th course are the header courses. They are not half bricks, but regular bricks turned 90 degrees so that the long dimension is perpendicular to the plane of the wall. Thus, the bricks in the header courses are embedded in both wythes of the brick wall and therefore tie the two wythes of the brick wall together. Look at the header course that crosses the repaired area (the middle green line on Tomfh's picture above). There is a clear step/dogleg in the header course that had to accounted for in the repair by using a wedge shaped repair to transition one course into two courses.

The question is why/how has the left side of the wall settled relative to the right? I agree with LittleInch that the basement stairwell/entry area seems a bit suspect. I would suggest that the OP investigate that area a bit more for any previous repairs/modifications.

 

[Tomfh]

I agree it's important to understand the history, and what action (if any) was taken to underpin or otherwise stabilise the wall. If someone did remedial footing works there should be direct evidence of it. The owners can surely provide some information too, even if only the date they acquired the property.

I'd also recommend using a laser level around the whole perimeter to get a clearer understanding of the extent of the settlement. They are so useful for seeing how a building has moved.

 

[phamENG]

hardbutmild - I'm not so sure it's stopped. Check out the sill of the second floor window, just above the bay window roof. On the right side, the joints are opening even more despite almost a full course of mortar being packed in there. It may well be the result of a recent change in the area. I think a geotechnical engineer would be a worthy investment here.

 

[kipfoot]

I'm convinced. The coincidental alignment of the bed joint tricked my eyes, but there's too much contrary evidence:
1) header course sift;
2) foundation work done where you would expect the shift;
3) facade work done where you would expect the gargantuan crack to have been;
4) the bed joint shifts up at the gable above the top window;
5) there are certainly other issues/evidence inside this building where they fudged sloping floors, skewed windows, etc.;
6) in the photo with the broom and rake, it looks like the neighboring building may be a candidate for a similar thread.

 

[hardbutmild]

It may well be the result of a recent change in the area. I think a geotechnical engineer would be a worthy investment here.

I'd expect this to be the case. Maybe I didn't explain well. I meant to say that if the settlement is still active after a 100 years, it's almost certainly because of some recent change in the soil near a structure.

 

[lubos1984]

I'm considering making recommendations to the client to retain a Geotechnical Engineer to investigate what underlying foundation issues may have contributed to this differential settlement. The owner's just purchased this home and have no knowledge of what kind of repair work has been completed in the past. The foundation parging does look recent but doesn't seem to show any issues ?
There also doesn't appear any evidence of any previous underpinning or remedial works to the foundation.

There are some great forensics here! I've attached a few more pics if it helps in any way. Thank you all for taking the time to analyze this in detail!

 

[phamENG]

The foundation parging does look recent but doesn't seem to show any issues ?

Exactly. There's no telling what that parge coat is covering up.

 

[r13]

Thanks for gte447f's explanation on the multi-wythe wall construction. It is odd to lay the header in offset layers, but I doubt it is due to settlement. Are you guys suggesting the settlement has occurred as shown in the sketch below? Where is the vertical shear plane though?

 

[bones206]

Not sure about real estate laws in Canada, but I feel like this condition should have been disclosed by the seller or at least flagged by an inspector. The buyer should have some kind of legal recourse.

 

[phamENG]

At the bay window. There's no picture at the foundation on the right side (based on the new pictures I'd say the back side) of the bay window. More than likely there won't be a visible break - there's probably a header over the bay window. I'm curious - any slope in the floor inside?

 

[hardbutmild]

@r13
I don't think that the vertical shear plane would even develop, it's easier for masonry to have some sort of staggered cracking pattern, rather than a straight one. If the part on the right is stiffer it would cause diagonal cracking (at about 45° clockwise from the horizontal) as the left part was lowering because the bricks are interlaced.
Also, some masonry structures can deform with less cracking, an extreme example would be the ancient byzantine masonry that's famous for having very thick bed joints to allow for significant displacement.

 

[dauwerda]

There were already a few posts depicting the shear plane, but here is another:

Also note the angle of the sill in the above image.

 

[gte447f]

@r13, Look at Tomfh's first annotated picture post (5th post in thread on 2 Dec 20 23:04). The "vertical" shear plane is sketched in red. Most of the shear plane occurs through the 3 window openings at the 1st, 2nd and 3rd story levels. The only real resistance through the masonry is between the top of the 2nd story window and bottom of 3rd story window, and between the top of the 3rd story window and the roof line, and it just so happens that those two areas are where the brickwork has been previously repaired.

 

[r13]

I don't think that the vertical shear plane would even develop, it's easier for masonry to have some sort of staggered cracking pattern, rather than a straight one.

I agree that there may not have visible vertical crack, for a smaller amount of settlement over considerable distance. However, the vertical offset is nether small, nor far apart (over a window). There should be at least a vertical strip of bricks exhibit distortion. Other than the damaged and badly repaired area, I don't see such indication.

 

[gte447f]

dauwerda beat me to it. Excellent depiction, dauwerda.

 

[r13]

dauwerda,

It is culpable, but I reserve my doubt.

 

[phamENG]

r13 - the bricks did crack apart and shift. That's why somebody ripped it out and put that abomination of "masonry repair" in between the second and third floor windows.

 

[phamENG]

r13 - if you have doubts, where are they coming from? What is your theory that doesn't involve foundation movement?