1. ATTENTION returning members. If you are coming here from the old forum for the first time, you will need to reset you password. However, we had an email problem getting password reset links set out to a lot of the email addresses. That problem is temporarily rectified but IF you still have an issue, email me direct at info@thebuildingcodeforum.com and I will give you a temporary password.
    Dismiss Notice
  2. Welcome to the new and improved Building Code Forum. We appreciate you being here and hope that you are getting the information that you need concerning all codes of the building trades. This is a free forum to the public due to the generosity of the Sawhorses, Corporate Supporters and Supporters who have upgraded their accounts. If you would like to have improved access to the forum please upgrade to Sawhorse by clicking here: Upgrades
    Dismiss Notice

All-masonry fireplace hearth bears on wood floor structure

Discussion in 'Residential Structural Codes' started by Willin, Nov 10, 2018.

  1. Willin

    Willin Registered User

    Joined:
    Nov 10, 2018
    Messages:
    3
    Likes Received:
    0
    New construction, a large freestanding fireplace with CMU core and fieldstone facing comes up through the wood-framed floor structure of the main floor. It goes through the basement floor where it bears on a suitably-sized pad.

    The fireplace opening is 16 inches above the floor, and the hearth extension, 100 percent masonry, sits atop the floor structure. It is not connected to the fireplace structure other than with mortar along the joint. No cantilevered concrete shelf will be built. This hearth extension has CMU core with fieldstone facing and its top is paved with bluestone.

    Code-perfect?
     
  2. cda

    cda Sawhorse

    Joined:
    Oct 19, 2009
    Messages:
    14,903
    Likes Received:
    869
    welcome
     
  3. cda

    cda Sawhorse

    Joined:
    Oct 19, 2009
    Messages:
    14,903
    Likes Received:
    869
    If you can convert the plans or draw a simple plan,

    Make it into a web link

    Post it would help.

    I am not in to structural, but seems like a structural engineer, might should be involved.


    So what does the fireplace set on?? a concrete basement floor, or wood basement floor???
     
  4. Willin

    Willin Registered User

    Joined:
    Nov 10, 2018
    Messages:
    3
    Likes Received:
    0
    Don't know what it takes to be able to include an image. So here is more detail.

    A large pier pad is directly beneath the 4" floor slab in the unfinished basement. Atop this is built, with CMU walls, the fireplace foundation, which rises up and through the wood-framed structural main floor about 8 feet above. A framed opening in that floor structure is for this fireplace, and the opening comes to all sides of the fireplace foundation, with about 1" clearance.

    Above this floor, the CMU is stepped in a distance for the fieldstone cladding thickness. The fireplace stack rises 16 inches, where the fireplace opening begins with its firebrick floor. The fireplace opening is thus 16" above the wood-framed floor.

    Sitting atop this wood-framed floor and abutting the front of the fireplace is the hearth extension, all-masonry, CMU core, rock faced, 2" bluestone slab atop it, the bluestone slab top elevation same as the fireplace floor which it tightly abuts.

    Note we've not built this masonry fireplace with a cantilevered slab below the hearth level, for supporting not just ht the hearth, but any hearth extension. We have built the extension as a separate masonry mass, sitting atop the wood-framed floor structure.

    Code?
     
  5. Willin

    Willin Registered User

    Joined:
    Nov 10, 2018
    Messages:
    3
    Likes Received:
    0
  6. cda

    cda Sawhorse

    Joined:
    Oct 19, 2009
    Messages:
    14,903
    Likes Received:
    869
    Give it a few days and there are plenty of people that speak structural that can reply
     
  7. TheCommish

    TheCommish Sawhorse

    Joined:
    Sep 27, 2011
    Messages:
    721
    Likes Received:
    54
  8. ADAguy

    ADAguy Sawhorse

    Joined:
    Sep 11, 2013
    Messages:
    2,577
    Likes Received:
    218
    He already said what it sat on, the hearth is on wood and the FP sits on a footing, a crawl space install.
    The concern here is the grout intersection between the hearth and the face of the FP. Hot coals can collect sometimes at this intersection and over time can char the hearth support members.
     
    cda likes this.
  9. jpranch

    jpranch Platinum Member

    Joined:
    Oct 17, 2009
    Messages:
    1,881
    Likes Received:
    68
    The living room floor at code minimum would have to have the capacity to support a 40 pound live load and a 10 pound dead load. I would be hard pressed to approve something like this and would require an analysis by a structural engineer. Been inspecting buildings for about 29 years and have never seen anything like this. The hearth extensions that I have seen have always been supported by cantilevered concrete.
     
  10. RJJ

    RJJ Platinum Member

    Joined:
    Oct 17, 2009
    Messages:
    2,889
    Likes Received:
    41
    I agree with Commish & jpranch.
     
  11. jar546

    jar546 *****istrator

    Joined:
    Oct 16, 2009
    Messages:
    5,671
    Likes Received:
    246
    The framing that supports your hearth needs to be of sufficient design for the loads imposed. The framing requirements are above and beyond the scope of the prescriptive tables in the IRC, therefore you would need a structural engineer as code inspectors, plan reviewers, etc are limited to enforcing prescriptive methods in the code books.
     

Share This Page