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Mono slab pour suggestions - Chimney/fireplace

Usafexplorer

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We are getting ready to order a cold formed steel building for a residential build and I'm trying to plan for the foundation requirements in the 2018 IBC for thickness and footing requirements for a chimney & fireplace. When pouring this slab, does the entire slab get poured in one singular pour or should the wraparound porch slab by poured at later time? Not sure if it matters but figured I would get the pro opinions here before I start calling around for bids. Thanks!
 

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ConCretin

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There is no right or wrong answer. It's definitely more cost effective to place it all at once but it depends on the details. Is there a lip between the main slab and the porch as d300 suggests? That would require a suspended edge form, which isn't all that difficult but often leads to problems. The chimney footing could be constructed integrally with the slab by thickening it and possibly adding some rebar. If it were my project, I'd definitely be looking to place it all at once.

Take a look at my Guide to Floor Slabs in the link below for some additional thoughts on placing a slab on grade. If you can provide some additional details, we might be able to offer some more responsive comments.
 

readhead

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If the building is an ACT product and you shared your requirements with the sales person the foundation design should be included with the building purchase.
 
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Usafexplorer

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If the building is an ACT product and you shared your requirements with the sales person the foundation design should be included with the building purchase.

Well that is actually why I'm here......

It is an ACT product and I brought this question up with the salesman and he said not to worry about the chimney/fireplace in the foundation plan. Which is not correct according to 2018 IBC I need to account for a 12" footing at least 12" outside of the fireplace perimeter.
 
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Usafexplorer

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If it's just wood heat you are after, a wood stove doesn't need a stone/masonry chimney.

Agreed it's not required but I'm quite sure my wife won't go for an exposed stainless chimney pipe so I might as well factor in the chimney weight now.

**Edit
Although you bring up a good point, I could do a framed out chimney chase and add stone veneer to give it the look she is after. Thanks!
 

chinboys

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Watch the Bondo channel on YouTube.
He pours monolithic slabs with perimeter footings in upstate NY. The footings seem not at the frost level and he uses several inches of closed cell foam to prevent the forst from heaving the pad.
You have to also check with your local codes too.
 
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Usafexplorer

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Is this a dwelling? If so did you mean IRC, not IBC?

It is a dwelling, but everything the county references is to the IBC 2015.


Which Residential Building Code does North Carolina use?

As of March 22, 2025, Jones County, North Carolina, is under the 2018 North Carolina State Building Code, which is based on the 2015 International Building Code (IBC 2015), and will remain in effect until June 30, 2025

The North Carolina Building Code 2018 is based on the International Building Code 2015 (IBC 2015) with amendments and additions.
 
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readhead

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Press the issue with the salesman. Either he is inexperienced or didn’t want to deal with it. They have to run it through engineering and it is an extra cost. He could have rolled it into the price. Now he is going to look like an idiot. If you don’t get any help go over his head. Is this by any chance through Metal Sales?
I have sold and erected metal buildings for over twenty five years. I recently retired but I have had mostly good experiences with ACT. Metal Sales should not be in the building business.
 

billconner

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It is a dwelling, but everything the county references is to the IBC 2015.


Which Residential Building Code does North Carolina use?

As of March 22, 2025, Jones County, North Carolina, is under the 2018 North Carolina State Building Code, which is based on the 2015 International Building Code (IBC 2015), and will remain in effect until June 30, 2025

The North Carolina Building Code 2018 is based on the International Building Code 2015 (IBC 2015) with amendments and additions.
OK. I think the NC Building Code references the International Residential Code for dwellings but maybe not. The international Code Council and UpCodes also points to the IRC.
 

BurtEggley

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sort of along the same lines but just thought I would share since we have had recent fires out here. Insurance now prefers, besides the normal no plants within 5' or more of the house, that the bottom of any flammable material is at least 6" above finished grade. Finished grade includes sidewalks. The reason being that wind blown ash and embers pile up against the house. They give a discount when the home is built this way, as well as some other things one can do to minimize fire risk. That is something that might be taken into consideration when planning the foundation and slab of a new home. After the Santa Rosa fire, it became obvious that all homes can be at risk, even in well groomed tracts. Looking at other states, one can consider the 10.000 acre 2016 fire in Eastern TN near Gatlinburg, where being on the east coast was not a guarantee of safety. I am only bringing this up because if I was planning a new home, I would want to minimize the cost of home owners fire insurance, and some of these standards may end up being adopted nationally within a few years. It would be best to plan the foundation and slab to incorporate some of these standards that might save money over time.
 

mike93lx

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where being on the east coast was not a guarantee of safety
The amount of fuel on the ground in all the forests surrounding houses on the east coast is terrifying. I've always tried to keep the areas around my house cleaned up but it probably doesn't matter when damn near no one else does it. When fires do get going, they'll be big
 

NUTTSGT

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You 'could' cast the slab in one piece but...you really should cast the porch slab as a separate item and drop it down an inch against the building slab to help control water.
I can tell you what will happen if you pour the entire slab at one time.

You'll be coming back starting a thread about water coming in under the walls..
 
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