I have a customer that we dense packed the attic floor of their house and airsealed around the masonry chimney.  The problem is the red brick chimney condenses in the attic. This has caused the floor around the chimney to heave and the ceiling below to stain.  The attic is 1260 square feet and is pretty leaky to the outside.  The customer states the problem has only occurred since we did the work.  Can any one give me some ideas what would cause this issue?

Views: 1658

Attachments:

Reply to This

Replies to This Discussion

It seems to me the chimney is probably cold, being connected to the outdoors.  So the moisture is coming from the surrounding air.  If keeping moisture out of the surrounding air is not practical, I'd suggest insulating the chimney with fiberglass batts with a vapor barrier on the outside.  Does that sound reasonable?
Is the chimney lined? It could be from flue gases from an unlined chimney. Any problem with condensation on the roof sheathing?

The condensation is from the flue gasses condensing inside the chimney.  This will be increase  as the attic temp drops. ths cools down the brick which allows the flue gasses to condense out at a greater rate.  If there is no clay liner or a flexible chimney liner in the chinmey one will neeed to be installed.  

This has been happeneing before but because the attic was kept warmer do to the heat loss through the ceiling it would only have shown up when it got colder outside.  Now that the attis is seperated from the house there is not enought heat to keep the bricks warm so more condensate from flue gasses is present.  

The condensate is mildly accitic (like lemon juice)  It will turn any paper products a dark chocloate brown after a while.  This is one way to tell the difference between a roof leak and condensate.     

 

All gas furnaces produce water vapor as a by product of combustion adn need to be addressed when furnace, water heaters and such are changed out-   You will need to recommend a chimney liner.

http://oee.nrcan.gc.ca/residential/personal/chimneys.cfm?attr=4  the link will give you a explanation, even though it is canadian, they expriance the problems much more than warmer climates

RSS

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

Jenn Saunders replied to Jenn Saunders's discussion iEnergyApp: Quickly generate professional reports for homeowners and get more contracts!
"Hey Tom, You are most welcome.  iEnergyApp is not free, but it is reasonable and pays for…"
14 minutes ago
Jenn Saunders posted a photo

Automatically Generate Clean Simple Reports for Homeowners

Stop spending hours cropping and resizing images, formatting and reformatting a Word document to…
22 minutes ago
Eric Sperline added a discussion to the group Energy Auditing Equipment for Sale, Trade or to Purchase
Thumbnail

Beware ebay seller "supermomofps"

I bought a blower door system on Ebay from "supermomofps"  The item was never sent and…See More
52 minutes ago
Larry Nissman replied to John Shillito's discussion Fixing a water heater?
"I have to agree with Kurt. 2000 ppm is exceedingly high. I have tested hundreds of hot water heater…"
54 minutes ago
Tom White's video was featured

Passive House Revolution - Film Trailer

Looking for energy-efficiency in buildings? There's no need to wait for new technology - Passive House buildings use 80-90% less heating and cooling energy.
1 hour ago
Diane Chojnowski joined Hal Skinner's group
Thumbnail

Radiant Control Coatings

A group where people who work with radiant barrier coatings can let others know all of their uses.See More
1 hour ago
Richard Beyer replied to Shawna Henderson's discussion High Density Foam -- Any Incidents of Cracking in Frame Walls as Studs Dry/Twist?
"Shawna foam pulling away from the studs due to over application will cause spontaneous…"
1 hour ago
Hal Skinner posted a group
Thumbnail

Radiant Control Coatings and their many uses.

A group where people who work with radiant barrier coatings can let others know all of their uses.See More
2 hours ago
Profile IconAlex Burnham and Annika Brink joined Home Energy Pros
2 hours ago
Kurt Shafer replied to Tom Conlon's discussion Whole House Fans - Love 'Em or Not?
"Reading the Invisco description you will find that it is designed to be surrounded by cellulose to…"
yesterday
Glen Gallo replied to Tom Conlon's discussion Whole House Fans - Love 'Em or Not?
"Kurt, I think cost of operation is always a factor but I am not sure I would leave it just cfm.…"
yesterday

Paul DelVaglio just added their location.
(via Member Map)

yesterday

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service