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Community and Q&A

Can we drywall over an interior chimney?

Becky Gaston | Posted in Interior Design on

We had a new roof installed and it leaked around the chimney, into our attic then seeped down into our hallway. Plaster covers the interior chimney. We have no fireplace, just a gas furnace and water heater. We plan on replacing all of the walls (which are plaster, also), with drywall. We’re just not certain about the chimney. The chimney is new also and has no liner. The company the built the new chimney said we didn’t need a liner since there is no fireplace. Any suggestions would be appreciated. Thank you.

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Replies

  1. GBA Editor
    Martin Holladay | | #1

    Becky,
    There are several issues here. One is the roof leak -- probably associated with inadequate or missing chimney flashing. Unfortunately, many roofers are unaware that, at a minimum, every chimney needs both flashing and counterflashing, and often requires through-chimney flashing. If your mason and roofer didn't understand these flashing issues, you can end up with years of problems.

    Second, there is the issue of why any mason would build a new chimney without including a liner. This is baffling. What appliances are vented through this chimney?

    The third issue is the one you asked about. If you want to install drywall around your chimney, you will have to build a stud wall to support the drywall. Building codes require 2 inches of clearance between masonry chimneys and combustible materials; this applies to wood studs, but it may not apply to steel studs. Talk to your local building inspector to confirm local requirements.

    Finally, plaster isn't combustible, so (as far as I know) you are free to install plaster directly against your masonry chimney if you want.

  2. Becky Gaston | | #2

    Martin;
    All of the above you mentioned regarding the chimney flashing, counterflashing etc. were done when the roof was put on. But it continued to leak. The roofers came out several times and replaced the flashing and finally found the leaks. As of now, there has been no more leakage. Regarding the issue of why the masonry guy didn't install a liner when they built the chimney, he said we didn't need it because the only appliances vented were the HOT WATER HEATER and the GAS FURNACE. Just for notation: the new chimney was only built from the roof up. Now my question is this; should we have a liner put into the chimney? Thanks on the advice of how to put the drywall over the interior chimney. By the way, we just had a new FLAMELESS GAS FURNANCE installed in August of 2013.

  3. GBA Editor
    Martin Holladay | | #3

    Becky,
    I am unfamiliar with the term "flameless gas furnace."

    Unlined masonry chimneys can work, especially if (a) the chimney is used only for gas appliances, (b) the chimney is located in the center of the house (rather than on the exterior of the house) or the house is in a warm climate, and (c) the appliances that are vented to the chimney have a high BTU/h rating.

    If the chimney is cold, and there is only one appliance connected to it, the "orphaned water heater" problem can arise; the usual solution is to install a metal lining. But it doesn't appear as if you have that problem.

    For more information on orphaned water heaters, see When a Flue is Too Big.

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