New Chimney

[Rotro]

I need direction or reassurance about my recent chimney build.

The original chimney was cantilevered off the main room, wood frame and vinyl siding. We could plant stuff below it in the flower bed area. Well it rotted after 25 years.

The company I hired was to replace all this with full brick on wood frame, so I take that as brick veneer. We picked out the brick from a local company and it was just regular brick I guess you could say.

Including the basement wall and the attic, it's almost 3 stories of brick.

I didn't know anything about anything concerning chimneys but as they were leaving, I could see underneath the slab on the downward side of the slope. I could stick my finger under it.

(My questions below in my thinking process are rhetorical until the end)

That's when I wondered what in the heck is supporting this thing? I found out there is no footing but rather they supposedly attached to my foundation – cantilevered – and a slab on that flower bed. They say they drilled into the foundation and attached those three all-threads in the photo.

I hired a structural engineering firm to check it out. They looked at the pictures the company sent them, and I included with this post, and determined it's fine. They said it's cantilevered off the foundation.

"It is our opinion, based on a visual inspection, that the new chimney is constructed adequately. The connection between the new chimney slab and the main foundation can withstand the anticipated loads, however, the south end of the slab could settle over time as a result of not having a proper footing."

This is simply hard for me to swallow...

I asked how they could calculate that from these photos? No one inspected the wall, no one knows the stresses already on the wall or it's integrity or how it was made. Freeze level? In fact that's a finished basement wall and no one ever went inside the house. There was no brick chimney before, nothing on the foundation, so how can a builder just assume that the foundational wall can handle 3 tons of bricks or more hanging off of it on one side - by three all-threads?

The NFPA describes the foundation for a masonry chimney, but apparently that doesn't apply. Isn't it the weight what the homeowner is worried about, so three stories of brick veneer is about the same weight as a one story masonry chimney?

I have looked and looked and looked. I see where it was discussed here 12 years ago, https://www.hearth.com/talk/threads/building-a-chase-questions.109954/page-2 but that doesn't really say this install is actually wrong…

How do I find out? Hire another structural engineering firm or just believe the first one? Maybe you guys will say it's acceptable. I don't know what to do.

Thank you, James

 

[Rotro]

By the way, they responded with the same opinion. They even added I didn't even need the supporting soil.

Come on... I don't believe it.

"I do believe the potential for any movement is negligent if not zero. The connection of the slab below the bricks to the foundation was done well and is considered a fixed connection and gives the slab the ability to cantilever from the foundation without the support of the grade below. Of course, there is soil supporting below, so it only help in your situation. I just want to comfort you knowing the the physics and mechanics of the structure as is, is quality."

 

[Rotro]

But they also said, and it is an engineering company, that I need to add backfill in this photo, marked by the red line, and tamp it down.

"Moving forward, at a minimum, I would recommend backfilling the soil around the slab so there is not cavities as shown below. I would tamp the backfill, and I believe that would mitigate any concern."

Is this how everyone adds a brick chimney? That J-Channel for siding even is after I had some guy stick that in because they put the brick and frame up to the siding. I don't know how to get an answer I believe, because an engineering report on this cost me 900 bucks the first time.

 

[Dieselhead]

I imagine a lot of the frame is nailed to the studs in the wall as well? If so it would absorb a lot of weight. That being said I’d of poured a true footing if it were my house.

 

[Eman85]

Don't know what you're looking for. Since it's already there it is what it is. Your choice to pour some concrete, backfill, or do nothing. Other alternative is tear it down and dig footers, pour concrete and rebuild. I'm guessing there's a class A chimney inside of a wood framed chase that they laid brick over. Did they tar paper the wood and use wall ties? What's at the top to stop water?

 

[Geezer77]

I don't suppose you pulled a building permit. The building inspector (at least here they do) would have made sure the construction met codes.

 

[Rotro]

No building permit required for my area since they're considering it a repair to an existing chimney. We're in the country so there's minimal requirements anyway.

I hired a different engineering firm to inspect. Required footing scheduled to be installed.

 

[Whitenuckler]

I would have thought they'd put 4 inches of rigid foam down before pouring concrete. You get below zero C there, and the ground may freeze and heaveup. Here they built real a real masonry chimney (1972ish) and it's sitting on it's own part of the footing/wall. These chase ones are different in that they have a wooden frame attached to the house.

 

[bholler]

No building permit required for my area since they're considering it a repair to an existing chimney. We're in the country so there's minimal requirements anyway.

I hired a different engineering firm to inspect. Required footing scheduled to be installed.

Very good. No way that was going to hold up long term.

 

[bholler]

I would have thought they'd put 4 inches of rigid foam down before pouring concrete. You get below zero C there, and the ground may freeze and heaveup. Here they built real a real masonry chimney (1972ish) and it's sitting on it's own part of the footing/wall. These chase ones are different in that they have a wooden frame attached to the house.

4" of rigid foam isn't going to change anything for a chimney footer.

 

[Whitenuckler]

4" of rigid foam isn't going to change anything for a chimney footer.

I'm not 100% sure I understand what the contractor did. Before it was a wood chase with siding, and now I see brick. Is that just veneer or is it real brick? Even if it's veneer I guess that would have more weight than before. Yes you are right, the foam would do nothing really as the new concrete is attached to the house foundation with rebar, and the ground has nothing really to do with it beside looking like a real footing and wall.

 

[bholler]

I'm not 100% sure I understand what the contractor did. Before it was a wood chase with siding, and now I see brick. Is that just veneer or is it real brick? Even if it's veneer I guess that would have more weight than before. Yes you are right, the foam would do nothing really as the new concrete is attached to the house foundation with rebar, and the ground has nothing really to do with it beside looking like a real footing and wall.

It looks like a full masonry structure to me. And no that cantilevered structure is not adequate.

 

[Whitenuckler]

It looks like a full masonry structure to me. And no that cantilevered structure is not adequate.

I reviewed it all and I would not really call it a full masonry ie it is still the wood frame with brick instead of vinyl siding
as an exterior. Correct me if I'm wrong, but a "full" masonry is built with brick and clay liners (at least in my house) and no wood.
I 100% agree that contractor should have had the footings ect. To go to that effort, and not start correctly is a shame.

 

[bholler]

I reviewed it all and I would not really call it a full masonry ie it is still the wood frame with brick instead of vinyl siding
as an exterior. Correct me if I'm wrong, but a "full" masonry is built with brick and clay liners (at least in my house) and no wood.
I 100% agree that contractor should have had the footings ect. To go to that effort, and not start correctly is a shame.

Yes but he said full brick. That is 2 to 2.5 cubes of brick depending if they are cored brick or not the brick alone is 3 to 4 tons. Add another ton of mortar and yes it needs an actual footer. A cantilever could work fine if the foundation was designed for that force. But I pretty much guarantee that it is not. Its just designed for compressive force. So even if they attached the cantilever correctly I doubt the foundation will hold it

 

[Whitenuckler]

I'm glad the OP is on top of it, and it's going to be fixed up. That's a lot of brickwork.