Existing Mortar Joint Cracks at Joint Reinforcement 1

That ladder "reinforcement" is useless stuff. I think your simple diagnosis is correct.

Hokie, Thank you for your response! Greatly appreciated.

Any one else have other thoughts?

And is it bad that my first thought on existing building projects is "How am I going to get sued for this"?

Yes, I think that type thinking is not good for you. You are there to solve problems, not fear them.

What kind of joint reinforcement and what gauge? - One piece ladder for the block and extended tabs for the brick or eye and pintel for the veneer?

Is the wall a true cavity wall or is there filled collar?

Usually, the problems with joint reinforcement corrosion come from poor placement and lack of external cover. - At least, raked joints were not used for "architectural" effect.

It is scary to see those photos and imagine what may happen in the future.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

Dick,

It's a 4" brick, 8" block, 12" total wall thickness. My guess is it's just ladder reinforcing, no tabs based on the wall section I have (see below). And it's not typical everywhere on the wall, just a few places here and there. There are some isolated areas where it's a problem, but overall the building facade has held up well. My guess is the original masons put these couple too close to the edge.

Thoughts?

It may be that, over time, the concrete continues to shrink and the brick continues to grow. The joint reinforcement doesn't know what to do and is being stressed in the process. This might be imparting stresses in the brick mortar, causing it to pop and let water in.

I believe pintels are the much preferred detail as they allow the brick and block to do their separate things.

Njlutzwe:
Is there any chance that moisture is getting into the wall in some way, from above, and exacerbating the corrosion problem. Are these locations up near a wall cap of some sort or up near a parapet or under a leaking window sill? Check these for any water intrusion possibilities. Because, otherwise the tooled mortar joints look very good. What do those same joints look like on the conc. blk. side of the wall? How deep is the wire in that mortar joint? Maybe open up a small portion of the wall on the brick side and see how deep the corrosion goes. Since, for the most part, the wall seems to be performing well, is there any chance of opening us those brick joints several feet past the point where the reinf’g. wire is in good condition again and bonding a couple new wires into the joint as it is tuck pointed back up? In terms of ties btwn. the brick and conc. blk. there are several screw type (spiral twisted, but can’t think of the names) which are screwed into a pre-drilled holes through the brick mortar joints and into the conc. blk.

If you are a licensed professional engineer, there is inherent liability in everything you do. hokie66 said it well. You can be sued whether you do a good job or a bad job. Solve the problem first.

I agree with your assessment. Water intrusion has likely caused exfoliation and expansion of the wire in the ladder "reinforcement" (agree again with hokie66 on this stuff). You also have other issues working on this.

Notice that the mortar is cleanly pushed out from the joint. This indicates the mortar was not bonded to the brick. There is not enough exfoliation volume in the wire to push the mortar out that far. It is likely that wet/dry cycling and/or thermal cycling contributed to this additional movement.

Keep in mind in the repair that you have to be cognizant that you have a waterproofing layer on the substrate wall that you do not want to compromise in your repair method. Further, check the condition of the thru-wall flashing at the base of the wall to make sure that it still works. Otherwise it should be repaired as well.

When you decide on a mortar mix for repointing, make sure it is compatible with the existing mortar or repoint the entire wall.

Good luck.

Ron, thank you.

DHengr, thank you too. To respond to your ?'s:

I don't see any efflorescence anywhere on the wall so I don't think there are any major water issues as I would expect to see them some if there were. The locations are sporadic, but at least a few feet away from parapets and sills. I can't see the joints on the concrete block side of the wall. I don't know how deep the wire is into the joint, but I think it likely varies. To my knowledge they aren't experiencing any other issues besides this and haven't for the past 35 years. As of now I'm going to go recommend having a contractor expose some of the mortar joints I didn't have access to prior to the work. Then I'll get a better look. Then, assuming no other issues I'm going to recommend tuckpointing and installing new retrofit brick ties at 16" o/c where the existing ladder reinforcing is corroded.

While I want to be thorough, I also don't want to conduct a witch hunt. What I mean by that is, that I don't want to open up the wall and find 10 other things that are potential problems. I think in any building you could do that, and where do you stop. If I see something glaring other than what I have seen I'll address it, but I also don't want to go exploring until I find something either when the problem seems simple enough. Especially when they haven't informed me of any other issues and I see no evidence of water damage other than at these joints.

Any thoughts on that?

nj.....just be sure that you meet the standard of care of your area for such an investigation and repair. I agree that a "witch hunt" is not warranted, but if you open a few joints, you have an obligation to look into the cavity as best you can to determine conditions there. Make your recommendations and let those with the checkbook decide.

Ron, thanks and well put. I plan to when they get a contractor on board to complete the work.

Thanks to all!