In really old homes, why are the fireplaces sometimes sealed off?

1. 83

   Efficient Adminposted 10 years ago

   In really old homes, why are the fireplaces sometimes sealed off?
   
   I noticed on the MLS listing a few really old homes built back in the early 1900s that have several fireplaces, but they are all sealed in with concrete. Why is that?

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2. 52

   grillrepairposted 10 years ago

   Fireplaces are actually a lot more inefficient than most people imagine.  The way the flue works atmospheric pressure creates a "pull" that sucks air and smoke and fumes out of the fireplace.  When I need to test someone's fireplace I sit in front of the fireplace, light a match and blow it out.  If the flue is pulling properly the smoke coming off the match will be sucked into the fireplace because the flue is pulling.   When the fireplace is not being used (like summer) the air conditioning in the room gets sucked out of the house.  In winter the central heater air gets sucked out.  If the fireplace is not being used it can cause a lot of loss of climate control.  Many of our clients will  seal the fireplace at the termination and then install a vent-free gas fireplace in the future.
   
   Second reason is damage.  Here in Florida we get hurricanes and very strong storms.  If a strong wind rips-off a termination cap it is likely the tension of ripping off the cap will cause damage inside the flue where the pipes are joined to one another.  Then the flue leaks which is very dangerous and very expensive to repair.  It is usually less expensive and easier to seal the chimney and run a gas line for a ventless gas fireplace.
   
   Non-Use efficiency problems and flue pipe damage are the 2 reasons I have seen most often and I have been working on fireplaces for about 14 years.

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   1. 83

      Efficient Adminposted 10 years agoin reply to this

      I have a wood burning fireplace and sealed it with a sheet of painter's plastic because of the strong draft and wasps getting in. I haven't used this fireplace in 7 years. The flue is closed though.

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   2. 52

      grillrepairposted 10 years agoin reply to this

      Plastic is not going to stop a persistent wasp. Is flue sealed by your plastic or is damper simply closed? Seal the flue by sealing (welding) the damper or removing the termination and cover the hole with flashing.

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   3. 83

      Efficient Adminposted 10 years agoin reply to this

      Damper is closed. I guess I was confusing the damper and the flue. The damper is the thingy you open for ventilation of the smoke to the outside? If so, what is the flue?

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3. 60

   duffsmomposted 10 years ago

   Fireplaces, while very nice to look at, are notorious for creating a draft and cold spots.  They don't heat effectively and are more for looks these days unless you have a fireplace insert or a wood stove.

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   1. 83

      Efficient Adminposted 10 years agoin reply to this

      Quite frankly I do not like fireplaces especially the wood burning kind because they are very inefficient. On the other hand I love the smell of burning wood. I would not have a fireplace at all if it were my choice. They take up too much wall space.

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