Double wythe brick/block walls...veneer???

[_Conky]

Not a lot of experience with older brick/block walls. Existing 2 storey 40+ yr old house all walls as 4" brick exterior with 4" block backup, with bond bricks turned every 7th course. I believe that this is considered as an 8" masonry bearing wall...not 4" load bearing block with 4" veneer. The building depts around are extremely quick to call out 'brick veneer' can't be used for connecting or supporting any load whatsoever, no matter how miniscule. I don't think I am off my rocker in coming back at them that this is NOT brick veneer, but in fact 8" solid masonry bearing wall. Opinions or experience with this? Thx.

 

[Greenalleycat]

Can you provide a sketch? I want to make sure I've interpreted this correctly
Do you have brick stuck directly against masonry block?
Is there any reinforcement in anything?

 

[_Conky]

I only have this from existing house plans.

 

[Greenalleycat]

Neat, that's a very helpful sketch
My thoughts are a bit academic here as this construction is not at all typical here
If your beam or whatever can reliably socket into the wall onto both wythes I would consider it as an 8" wall
If it's just landing on the masonry block side then I would be a bit more hesitant
I guess the turned bricks will give you some composite action but I'm just not a fan of bricks over blocks!

 

[_Conky]

Yes we have 1000s of older 50-80 yr old houses around here like this...even more that are double brick, no block. And foundation walls in double and triple brick.

 

[Greenalleycat]

I've worked on a few double brick houses over the years, we have some here too
But the earthquake took care of most of the ones in my city before I entered practice so they're not so common day to day!
I've never seen the double brick-block structure like your place though

If it was double brick I would definitely be taking it as an 8" width with the 7th course transverse blocks, so taking off my conservative hat, it seems appropriate to do the same here

What's the actual context for this one? What upgrades are you trying to do?

 

[RPGs]

Here on the US east coast these things are everywhere in every configuration of unreinforced masonry you can imagine. I've inspected hundreds in Philly, Baltimore, Wilmington (DE), and everywhere in between. There are a huge amount of them just rotting away in lower income neighborhoods and you can buy one for $500 (no exaggeration).

Looks like the roof rafters land onto the top of the brick coursing. Not a veneer in my opinion.

 

[_Conky]

Adding a 2nd storey over the garage portion which is currently 1 storey. And upping the height of that existing garage wall from 8' to 11'...that's where I started worrying about width of wall for the slenderness check of t>h/20. Clearly single wythe wouldn't cut it, or even work for existing 8' height for that matter.

 

[_Conky]

RPGs...that is my thinking as well. However I will likely end up with a few significant point loads here and there from beams that I may ask them to slot in a steel post for, especially if they land near existing openings. And sides of existing garage door I don't like the idea of large concentrated loads either that could end up loading one wythe more than the other, so I'm thinking steel posts there as well slotted into the block wythe.

 

[Greenalleycat]

God the thought of doing that gives me the heebie jeebies
Hope you don't have earthquakes...

I think I would be adding in additional reliable structure regardless, but I have very limited experience in this so maybe that's not standard practice in these situations

 

[_Conky]

Greenalleycat...pretty much a zero EQ zone, not even a thought around here for most buildings, wind always governs unless it's something like elevated tanks, silos, etc.