What is a proper chimney crown?

Discussion in 'Bricks, Masonry and Concrete' started by travelover, Jun 4, 2009.

  1. Jun 4, 2009 #1

    travelover

    travelover

    travelover

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    My 43 year old chimney (in Michigan) has loose bricks and spalling in the top 10 rows for bricks. Looking at it closely, I can see that it never had much of a crown - just mortar spread from the tile liner to the edges of the top brick layer. I just installed a high efficiency furnace (PVC vent through wall) and an aluminum liner for the water heater, so there will not be much condensation, as in the past.

    I have 4 estimates with a price range of $1000.

    The highest bidder wants to rebuild the top 10 rows then spread some kind of synthetic material over the top that is "better than concrete".

    Mid bidder would rebuild 9 rows then cast a cement crown with 2" overhang.

    Low bidder would rebuild 9 rows, add a 2 1/2" thick limestone cap that over hangs, then use sloped fiber filled concrete from liner to edges.

    Since the old one lasted 43 years and in another 43 years, I'll be dead, how good is good enough?
     
  2. Jun 4, 2009 #2

    glennjanie

    glennjanie

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    Hello Travelover:
    I vote for the mid range bidder.
    Glenn
     
  3. Jun 5, 2009 #3

    travelover

    travelover

    travelover

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    Thanks, Glen. What tipped your vote?
     
  4. Jun 23, 2009 #4

    slownsteady

    slownsteady

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    Logic says if it lasted 45 yrs you could rebuild it exactly as it was. You probably want a drip-edge, but maybe two inches is more than necessary. i would also like to know what "better than concrete" is before the guy (any guy) uses it.
     
    Last edited: Jun 23, 2009
  5. Jun 25, 2009 #5

    travelover

    travelover

    travelover

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    I ended up going with the low bidder, but I'm entirely happy with the job. They crowned it with limestone which overhangs and topped that with a sloped fiber filled concrete cap. Once it was torn down I could see that whoever built it was a little short on flue tile so there was a 6" gap in the tile. No doubt this accelerated the decay of the chimney. They fixed the tile issue plus with my new furnace a few months back, an aluminum liner was added. So, I anticipate the chimney will out last me.
     

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