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gmmeyer 10-02-2010 01:45 PM

Is brick a decent insulator?
I have a fireplace in the middle of my ranch house in a brick wall that sections off the living room and kitchen/dining room. Currently I am insulating the attic in attempt to at least double the r value. On either side of the fireplace there are large air spaces in between the brick. maybe 3 by 5 foot and opens into the attic. Like two more chimneys going into the attic. Am I loosing large amount of heat through the brick wall into the attic? The floor of the attic is insulated, the roof is not.
I would rather not cover up the opening for fear that I will not do a proper job so that 10 years down the road some poor owner will walk on that covering and fall through and break a pair of legs if not worse. I will if I am loosing heat.

mudmixer 10-02-2010 02:19 PM

I really don't total understand the details of your layout.

Based on your statement that the attic floor is insulated,it sounds like your attic is intentionally not insulated. If you stop the circulation and the attic is warm, you can have ice dams. I assume you have roof vents, a vented ridge or gable vents.


GBR 10-03-2010 02:23 PM

Did the builder run the walls close to the fireplace chimney? Code requires 2" air space to the framing. Then use metal for air/fire stopping against the brick or block fastened on top the ceiling joists. Similar to page 2, sealing ducts: How to Seal Attic Air Leaks | The Family Handyman


mudmixer 10-03-2010 07:34 PM

A sealed attic without ventilation and air flow is asking for problem here (Minnesota).


GBR 10-06-2010 06:08 PM

Is the attic vented? It sounds like the chimney has a void area on a side of it that is a direct route for cold air from the crawl space?


Perry525 10-07-2010 04:57 AM

insulate to save on heating costs.
Brick is an OK insulator, as long as it is dry.
However, you need to look at this another way.
For a fire to burn well on tick over, you need a warm chimney, from this point of view you should encase the chimneys in at least 2 inches of polystyrene to keep the heat in the chimney.

At the same time you want to reduce your heating costs.
Again by keeping the heat in the rooms/chimneys you reduce costs.
Several inches of closed cell insulation will pay for themselves in a year or two of saving on heating costs.

Five inches of polystyrene will reduce your heat loss by about 80%

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