Cold basement, insulation question

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  #1  
Old 09-09-13, 02:26 PM
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Cold basement, insulation question

Hi - I purchased my 30ish year old split level house approximately two years ago. It has a fully finished basement, however I've found for the past two winters that it gets very cold in my basement rec room.

First off, I'm located in Nova Scotia, Canada. Thanks to our location on the ocean we don't tend to get that cold, usually no colder than -15 celsius (5 fahrenheit) in winter. My house has electric baseboard heat, and with it running constantly I'll be lucky if I can get the temperature in that room to around 19 C (66 F) on cold days.

So I decided to cut a few holes in my walls to see what sort of insulation I've got and here's what I've found:

My basement is partly underground, with the concrete foundation wall extending up around 4 feet or so. There is 2x6 framing on top of the concrete, with fibreglass batts. In front of the concrete is a 2x4 wall (floor to ceiling), which forms the interior wall. There is approximately a half inch gap between the 2x4s and the concrete (wood is not touching concrete), and there are fibreglass batts in the 2x4 wall, but only going up as high as the top of the concrete, at which point there are additional fibreglass batts cut and laid horizontally across the top. The vapour barrier and drywall are attached to the 2x4 wall. I'm attaching a picture so you can see what I'm talking about.

There's a gap of about 11 inches between the fibreglass insulation in the 2x6 framing (top half of the wall) and the vapour barrier. Is this normal practice? Shouldn't the entire wall cavity be filled with insulation right up to the plastic vapour barrier? This wall by the way usually feels cold to the touch during the winter.
Would it be worth while to fill this void with additional insulation or should I continue looking elsewhere for the cause of my problem?

Thanks
 
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  #2  
Old 09-09-13, 06:47 PM
Join Date: Mar 2005
Location: USA
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If you have split level home with a open stair case you will never get the basement really warm because you have uncontrolled air flow and the natural convection of the heat is the basement will cause the warm air to rise and the cooler air to settle.

If this is your case you might be able to put a door in to separate the living areas and minimize the conduction. Then all you have to do is find a way to insulate the lower living space from the soil that may be 55F, or the average annual temperature. This is even a common problem on homes forced air, but they can usually maintain a 1 or 2 degree difference between levels with a open stairway and uninsulated floors even in a colder winter climate (MN) than yours.

Just a thought -

Dick
 
  #3  
Old 09-10-13, 08:09 AM
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Thanks for the response - I should have mentioned that the rec room does have doors I keep closed that separate it from the stairwell, and the laundry room/rest of the basement areas.
 
  #4  
Old 09-11-13, 01:48 PM
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With any gap between insulation/drywall = convective loops; https://docs.google.com/viewer?a=v&q...fHFsk1RrK9G2HQ

Fig. 22; http://www.buildingscience.com/docum...-climate-zones Block the void to stop the heat loss, up to 40% of the R-value.

Gary
 
  #5  
Old 09-11-13, 04:18 PM
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Thanks Gary, good information. I'll probably just fill that gap with additional insulation and hopefully that will help out this winter!
 
  #6  
Old 09-11-13, 07:06 PM
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Short-term/inexpensive; caulk/canned foam around outlet boxes, gap at drywall/slab against air movement. Info-401: Air Barriers

Roxul is better at stopping air movement than say- fiberglass (think furnace filters), lol.

Gary
 

Last edited by Gary in WA; 09-11-13 at 07:07 PM. Reason: sp
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