Deck cantilevered fireplace

Inspected a house with a stand-alone deck that had a fireplace at the end of a screened in section. I’m not familiar with fireplace construction on decks. The fireplace was on a cantilevered portion with only side supports to the cantilever. I’m used to seeing chimney chases that are cantilevered, however, in this instance the fireplace hearth is sitting on unsupported portions of the cantilever assembly. I’m considering suggesting a SE look at it since it appears to me to be very questionable.

The exterior of the chimney chase

The supporting structure. Only the two outside joists are supported at the cantilever. NOTE: the wiring on the left side that goes up to a receptacle at the hearth.

This shows the location of the hearth above with the receptacle as a reference point.

Am I correct to call this or is this a normal fireplace installation?

I would call it out, Anthony…the cantilever looks less than professionally built, to me too.


Hey Larry, Thanks for the confirmation. Appreciate you being here on the weekend brother.

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The two outer joist are supported by the notched beams. No inner support is visible, however, are the notched beams support sufficient to hold the weight of the wood framing and siding of the chimney? Not sure, but I would defer to a framing/deck contractor before a SE. A few additional supports could be all it needs and a contractor could tell you that. An SE will charge you $800 to come out to say the same thing a contractor will. It needs to a little more support.

Btw, I do see outdoor deck fireplaces often.

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Hey Thomas, I threw in the receptacle as a reference to show that the fireplace hearth the is also sitting on the unsupported joists. It’s hard to tell in the photo, but like you said, only the two outside joists are supported. If the structure was only supporting the chimney chase I wouldn’t have a problem with it. But since it’s also supporting the weight of the hearth then I have cause for concern. There’s also stacked stone above the hearth. I’ll upload another photo.

those outer two joists are supported by the notched posts at one area and with hangers at the perpendicular joist.

The center 3 cantilevered joists are the problem. They are supported on one end at the hangers on that perpendicular joist. The other end they are supported by the rim joist that is nailed to the ends of the outer two cantilevered joists…dunno who thought that was a good idea

Calling for a Structural Engineer for further evaluation IMO is the right call.


It is of concern for the inner joist. My point was that a good decking contractor would most likely identify and make the necessary corrections. I would start there before elevating it straight to a SE.

We can agree to disagree… :stuck_out_tongue: :upside_down_face:

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Is it possible to do both, e.g., “Recommend further evaluation by a qualified deck contractor or structural engineer.” or would this open me up to liability?

That’s how I would word it. Let them decide and no, it lessens your liability. They choose, but you offered both options.

That’s what make this MB what it is Thomas, different opinions and solutions. :grinning:

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Personally I wouldn’t recommend both, I’m always telling my clients, would you want the same guy back to fix what he should have done right in the first place?

If you have an SE draw up a fix, the fix should be done IAW those drawings.

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I agree. For the cost of the engineer, additional supports could be installed. If I was the seller and the buyer had concerns, I’d just go ahead and hire a contractor to add some additional support. Engineers are for more complicated issues.


IMO, depending on the dead weight of the hearth and the stone work combined, not sure about the roof structure or possible snow-loads, that may require more than just adding a couple of posts.

I had a similar situation back in April. What are your thoughts on this set-up? - Misc. Discussion - InterNACHI®️ Forum

I agree that it would take more than a couple of support posts. As info, B’ham Alabama is the location so snows not an issue.


Damn Yankees and their “snow loads”… :stuck_out_tongue: :stuck_out_tongue: :shushing_face:

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Not necessarily. Depends on the size of the posts and the footings. It is not grossly under-supported as evidenced by the fact it is still there. There won’t be any additional live load added with no snow and no people standing in the fireplace. A person could also make a perimeter footing and use CMUs’ to build a foundation. The total cost of that would probably not be much more than the cost of an engineer to tell you to do that, lol.

I don’t suggest “fix” recommendations, but a proper footing, 6x6" post, 2x6" cut between the notched post on top of the support beam traversing the ‘hanging’ joist… :thinking: Don’t think I would call it out…

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Thanks for the info, Ryan. That’s what I love about this forum; always an opportunity to learn.