Vapor Barrier Question

[ekartal6]

[Brian A. MacNeish]

Originally Posted by rcooke

I think the have very high humidity needs an automatic Dehumidifier self draining even if it has to be put up on a table hose to sink.
...Cookie

Dehumidifiers will only bring the RH down to between 50& 60% , which may be OK for a humid basement in the summer (since mould will grow when ambient air RH's are 65-70% and higher.) In the winter, interior air RH's need to be as low as 30% in the coldest weather (below -10 to -15*C or 14 to 5*F) to keep severe running condensation off regular sealed pane glass. This facility probably should be looking into a high efficiency HRV both for moisture control and general air quality.

In homes with higher RH's, sometimes placement of furniture along outside walls can cause dead air spaces behind/ under the pieces or in corners. No convecting air with heat gets into these areas and the inner wall surfaces get cold enough to cause condensation and maybe eventually frost.

[Mario A. Kyriacou, CHI]

Check out this site guys.

http://irc.nrc-cnrc.gc.ca/pubs/bsi/83-2_e.html

[Roy D. Cooke, Sr]

Originally Posted by mkyriacou

Check out this site guys.

http://irc.nrc-cnrc.gc.ca/pubs/bsi/83-2_e.html

Great Thanks Mario now if I can just remember all of what I read be good.

...Cookie

[Brian A. MacNeish]

Originally Posted by mkyriacou

Check out this site guys.

http://irc.nrc-cnrc.gc.ca/pubs/bsi/83-2_e.html

Hi Mario:

In Moncton (1983), I attended the day long series of seminars by NRC researchers and others that this article was taken from. Back then the cost was about $125-$150 plus the day of missed work if you were private sector. It's funny how poorly attended these sessions were even though they addressed the issues of the day and are still very relevent today ( you just recommended one!!)

If my memory serves me, there were only 9-10 attendees at the Moncton
session- 5-6 were gov't employees from inspectors to architects and the rest were private- myself, a gent from a manufactured home company, and a couple of private architects. The small attendance made for a good session with lots of discussion and questions, not usually available with large audiences.

In dealing with interior moisture from new construction with HRV's/ERV's, a new paradigm has evolved- houses dry out very quickly in cool/cold climates with dry winter air. It was understood before air exhangers, that a house did not come to equilibrium (dry out) with the ambient conditions for about 18 months (e.g. some concrete is usually still not at equilibrium until 800-900 days).

In the 1980's, when were we installing HRV's/ERV's in new regular and R2000 homes, some homeowner's would call as we moved into the late Dec to Feb period and say the air was too dry. One owner, whose large home (it had hand plastered walls- thin coat veneer) was built during a wet fall from Sept to occupancy in mid-December, called with this complaint in late January. I told him to go to the unit and turn it onto "low" speed ( the manufacurer, Van Ee, had already added this extra low speed feature because of overdrying). He balked as he didn't want to go below the current air exchange rate because of concern for family health. I convinced him to do this and and call me if any problems developed.......no calls came later due health issues!!

[Mario A. Kyriacou, CHI]

Brian,

The cost has gone up for these seminars, I believe they are $400 or so but well worth it!!