I am planning to extend a half floor to become a complete floor, however this will cause it to encompass a double wall chimney pipe that is currently connected through the roof. To build this second floor I must construct a post on which will sit a primary beam, and from which two secondary beams will branch out on either side of the pipe. See diagrams below. These beams and post will be 5 1/4 x 7 1/8, and the post will reach 6 1/2' high. On average these beams have a space of 18" between them, but I have some leeway to place them differently. All members are to be from pine, including the 2x6 floor boards to be added eventually.

So, how far must everything be from these new members? I can only move the woodstove so far from the post because of a nearby door (is there shielding I can use if it is too close?), but the chimney pipe can be adjusted more freely in both directions. In the diagram I did not include the S-curve, but you can see it represented by the two pipes adjacent to each other. I live in Massachusetts in case that makes a difference.

I assume I will place some sort of apron or guard around the pipe where it goes through the 1.5" floor boards - I suppose there will be a minimum distance required here as well?

Chimney View #1

Chimney View #2

Chimney View #3

Current Setup

  • 1
    What? Jotul F3 - or a knockoff? Pretty sure it's already too close to the wood wall and railing as-is. Manual here if it's the real thing - see section 4 for clearances. jotul.com/sites/usa/files/products/…
    – Ecnerwal
    Commented May 16, 2023 at 18:17
  • It is a Jotul and someone else mentioned it was too close but I think this house was built to code so I'm not sure why it would be too close. I know it has a sort of plate on the back that could provide some shielding. I'll check out the manual, thanks! Commented May 17, 2023 at 0:08
  • 1
    Houses get built to code, and woodstoves get added later and sometimes are not done correctly or checked or inspected, until the house burns down and your insurance company laughs all the way to the bank while not paying you a cent. The rear heat shield on the stove is standard, and unless my sense of scale is WAY off, it's definitely too close to bare wood without at least additional shielding on the wall and railing (unless that's not part of the house and is just there for the chicks or whatever the heatlamp is for), and perhaps not even then.
    – Ecnerwal
    Commented May 17, 2023 at 1:43
  • It does look like it should be 25" where in fact it is 16" - do insurance companies really deny claims over something like this? Commented May 18, 2023 at 2:10
  • Absolutely. Does your insurance company even know you have a woodstove? Most charge more if you do, and want proper installation documented before they will cover the house at all with one; thus, denying a claim for one they didn't know about or that was improperly installed is all profit for them. That's how they remain profitable enough to fund all those nice commercials that make you think they'll cover your losses. Actually covering your losses is what you think they are for, but they have a very different view, in real life.
    – Ecnerwal
    Commented May 18, 2023 at 16:23

1 Answer 1


All pieces in a heating system have minimum distance from flammable surfaces.

Double wall chimney pipe will be a few inches, wood stoves more. If you lost/do not have the installation instructions or the labels are missing, your local fire/building department will know them.

The pipe will probably need an air gap housing/fitting for the floor.

  • 2
    Typical clearances to combustibles are 36" from a woodstove, 18" from single-wall stovepipe, and whatever the label says (2" on the last type I used) for multi-wall insulated chimney. Use of heat shields can reduce the stove and single-wall pipe clearances. Manuals for stoves and insulated chimney giving the required installation clearances can be found on the web, usually.
    – Ecnerwal
    Commented May 16, 2023 at 16:14

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