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Old 03-07-2012, 09:12 PM   #16
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Canada has it's own Codes without ignition barriers as our "I" Codes have:
"Effervescent paints have been used to meet USA Code requirements as an ignition barrier. The Canadian 1995 National Building Code does not require an ignition barrier over foamed plastics." From:

burnt03, you need to check locally if you need a thermal barrier over the foamboard, or not:
" Protection of Foamed Plastics
1) Foamed plastics which form part of a wall or ceiling assembly in combustible construction shall be protected from adjacent spaces in the building, other than adjacent concealed spaces within attic or roof spaces, crawl spaces, and wall assemblies
a) by one of the interior finishes described in Subsections 9.29.4 to 9.29.9
b) provided the building does not contain a Group B or Group C major occupancy, by sheet metal
i) mechanically fastened to the supporting assembly independent of the insulation,
ii) not less than 0.38mm thick, and
iii) with a melting point not below 650C, or
c) any thermal barrier that meets the requirements of Sentence (2) (See Appendix A.)From:

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17,000 dryer fires a year, when did you last clean the inside of the dryer near motor or the exhaust ducting?
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Old 03-07-2012, 09:54 PM   #17
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They don't have anything out newer than 1995....?

Come on guys. Stop making great hockey players for a hot second and update your code books...
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Old 03-16-2012, 09:08 PM   #18
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Wanted to check over a calculation from ( to see if it's correct...

Did a rough measurement from the living area to get an idea of the square footage of the attic.

Get about 25' x 27' = 675 sq ft.

Divided by 150 to get 4.5 sq ft (the total net free ventilation area)

Converted to inches = 650 sq in

With intake/exhaust ratio of 60/40, get

soffit = 390 sq in
ridge vent = 260 sq in

Does that sound correct?
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Old 08-31-2013, 08:41 AM   #19
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Looking through some old posts and have some new issues.

Early last year (after this post), I went up and cut out the 1x4 sections that were blocking the ridge vent. I also air sealed wherever I could reach. I didn't get a chance to clear out the soffits though.

Last winter was first year with a woodstove so kept the house quite a bit warmer all winter.

Up into the attic today to make sure the soffit venting was far enough past the insulation and there are more mold spots on the underside of the sheeting.

I wasn't in the attic during the winter but I'm sort of thinking that the warmer air in the house was making it into the attic but not vented out (since I hadn't done the soffits yet). So, had more condensation formed. With the soffits cleared and vented, I'm hoping that'll fix the issue.

Does that sound reasonable?

Last edited by burnt03; 08-31-2013 at 08:56 AM.
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Old 09-02-2013, 12:13 PM   #20
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If you have a well vented attic with the proper amount of insulation then the attic temperature should be closer to the outside temperature than the inside temperature. If that is not the case you are lacking one or both.


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