To Parge or not to Parge

by | Jul 17, 2017 | Fireplace, Maintenance | 12 comments

Fireplace smoke chambers have recently become a hot topic among homeowners (no pun intended)! Working on a minimum of four chimneys a day for the past seven years has given me plenty of time to think about and discuss the topic. First, we need to understand a little more about smoke chambers…

What is a smoke chamber?
A smoke chamber is the area above the fireplace firebox (where you see the fire) and below the flue (in most cases the flue is constructed of terracotta tiles), used to allow smoke to mix and rise into the flue.

What does the code state? 
The National Fire Protection Association (NFPA)-211 Code Book (2006) addresses smoke chambers in section 11.2.1.13, stating: “The inner surfaces of the smoke chamber shall be parge coated smooth, with an insulating refractory mortar…”
Likewise, the 2006 International Residential Code (IRC) states: “When the inside surface of the smoke chamber is formed by corbeled masonry, the inside surface shall be parged smooth.” (R1001.8)

Why does the code state this?
Parging, when done with the correct material, offers several benefits:

  1. Improves safety of the chimney
  2. Increases structural integrity of the smoke chamber area
  3. Typically improves draft and performance of the fireplace, thus lowering creosote buildup within the chimney system
  4. Returns smoke chamber to code compliant
  5. Makes it much easier to service the chimney properly


When can a smoke chamber be parged? 

A smoke chamber should be parged during construction of a chimney because this is, of course, the most thorough and cost-effective time to do so. A smoke chamber can also be parged after construction, any time of year, although it is much more difficult and expensive to do so.

Are most smoke chambers in our area parged?
It is tough to put a percentage on parged vs. un-parged but I would say less than half of the fireplace chimneys that I have seen were parged.

What does Paul Bianco of Chimney Savers think about parging? 
Well that’s a tough one… If your smoke chamber is not parged, technically this means that your chimney is not to code, and as a Certified Chimney Sweep by the Chimney Safety Institute of America, I am supposed to enforce the codes (IRC and NFPA 211).
But in my mind it really comes down to two factors: construction and maintenance.
By construction I am referring to how close combustible wood is in proximity to the fireplace smoke chamber. For example, is the chimney exposed above your mantel? Is it brick all the way to the ceiling? Or is there sheetrock covering the chimney where the smoke chamber is located? If, for example, your chimney is mostly exposed brick up to the cathedral ceiling in your house, that means that there is not really any wood touching the chimney in the smoke chamber area, and so it would concern me less. However if your chimney is completely enclosed (e.g, sheetrock or wood) it becomes more of a concern.
Now on to the second factor, maintenance. The largest concern with an unparged smoke chamber in my mind is that it leads to more creosote buildup and its irregular design that creosote is harder to remove. Yearly maintenance by a certified chimney sweep can obviously lower the risk of a chimney fire and thus alleviate some concerns of an unparged smoke chamber.

One more tidbit of info that I would like to add is that you should all be aware that parging a smoke chamber after the original construction is not a foolproof method. The construction of the chimney has a lot to do with how thorough and complete job can be done. There are many techniques and methods of doing this, which range from pressurized sprays to hand trowling. In most cases, after a chimney technician parges a smoke chamber it is still not perfectly smooth.

I cannot say that you do or do not have to have your smoke chamber parged. I am only trying to make you aware of the facts and let you decide for yourselves.

Thanks for your time and I look forward to working with you on a yearly basis.

Paul Bianco
Chimney Safety Institute of America Certified Chimney Sweep

URL Redirect – https://www.chimneysaversvt.com/parge

12 Comments

  1. Craig

    Do I need to parge my smoke chamber if it’s an out door fireplace with nothing combustible whatsoever?

    Reply
    • Rod Sarmardin

      Good day.

      I have an outdoor fireplace that needs parging to smooth out the corbelled bricks in the smoke chamber. I seen your you tube video and would like to ask if you have the mixture ratio for the refractory cement, type of sand etc.

      It looks like CSIA have done their own mixture in the video and any information will be greatly appreciated.

      I have searched Australian suppliers for Chamber Tech 2000 and Chamber coat and can’t find any and have decided to mix my own because they will have to be sent from the USA.
      I am using ISTRA 40 CALUCEM Refractory Cement.

      https://www.calucem.com/products/istra-types/istra-40.html
      Can you recommend ratio mixture advice to insulate the normal clay bricks I intend to use for the smoke chamber. I will be using ISTRA 40 CALUCEM between the bricks.

      Kindest regards

      Rod Sarmardin

      rodsarmardin1970@outlook.com

      romardin2806@gmail.com

      Reply
      • Paul Bianco

        Hi Rod,
        Unfortunately you may be confusing some info. We don’t have any videos on parging smoke chambers, I think you may be confusing us with the company Chimney Saver who makes chimney products.
        We always buy products that are premixed like Chamber Tech so unfortunately I don’t have any information on creating such a product from scratch. Best of luck sorry I couldn’t be more helpful.
        -Paul

        Reply
  2. Paul Bianco

    Hi Craig,
    Without seeing the fireplae i cant give you a definative answer. If its an outdoor firepalce I wouldnt think parging would be neccesary unless you found that the firepalce was not drafting correctly.

    Reply
  3. Brian Maples

    Hello, I have an old masonry chimney that is not parged and we recently had the firebox rebuilt for vent-free gas logs. There no damper but we we have a steel rain cap closing it off from the top, there was never a damper originally installed as far as we know. Now I’m being told that I need a plate or bottom style dampener to move forward with the gas logs. I would like to install a Cast-Iron Fireplace Damper and trim it within reason to fit and allow for expansion space an refractory mortar it in place and also parge upwards as much as I can reach into the smoke chamber. Since I’m going with vent-free I feel that it would work and look authentic. The fireplace was built around 1920 in rural Texas and below the firebox a foundation was never located just a fine dust or brick dust. If you could provide some guidance that would be greatly appreciated, since we are at a stand still due to not having any bottom damper

    Reply
  4. Benjamin Alicea

    Thanks for the valuable information! You guys are great!

    Reply
    • Paul Bianco

      Thanks for reading!

      Reply
  5. James Lewis

    If I am installing a stainless steel liner after a chimney fire am I required to parge the chimney under the IRC and/or NFPA 211 guidelines?

    Reply
    • Paul Bianco

      Hi James,
      You would have to check the local codes in your area but I would strongly recommend doing so if you are relining the chimney.

      Reply
  6. Heather

    Good morning. I have a question about my chimney that I hope you can answer. I have two fireplaces in two different levels of my house. They share a chimney, but two different flues. When I lit a fire in the upstairs fireplace, a small amount of smoke was drawn down the other flue to the basement fireplace. Enough to make it smell like smoke down there. Any ideas how to fix this?

    Reply
    • Paul Bianco

      Hi Heather,
      Feel free to email me and I will set up time to discuss this over the phone. I will need some more information to get a full picture. My email is Paul@chimneysaversvt.com

      Reply
  7. Stephanie

    I have a masonry fireplace that I converted from a wood burning unit to a gas unit. Is parging of the smoke chamber required?

    Reply

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