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Ask the Experts!

23 July 2008
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“How do we cool off the attic in a finished upstairs bedroom? We have a ridge vent and vents at both ends of the house and under the eves, they are not one long strip but individual vents and we installed other attic vents on one side, which helped a little. We have no shade on most of the roof and no place to plant any trees. The neighbors had trees but cut them down and now we can really feel the difference in the summer. We need to gut that room and would like to know what to do with the storage space. There is insulation on the floor and the knee walls.”

It sounds like the attic is adequately vented.  If the shingles are getting old and need replacing, switching to a light color will help keep the attic cooler.  If you are gutting the upper level it is better to not use the side attic spaces as storage.  Ideally the floors should have an R50 or 14″ of cellulose insulation, so this would not allow for storage.  The kneewalls should have an R11 + R19 batts.  The space between the joists below the kneewall should be sealed airtight so air will not flow into the attic space through the insulation.  The slanted section is the part that is the part that is overlooked the most often.  It should have an R11 batt and at least 2″ of foam board added to the bottom of the rafters before adding sheetrock.

Answer provided by Paul Morin, Senior Building Analyst at the Center for Energy and Environment.

One Comment leave one →
  1. bob permalink
    15 February 2009 10:48 am

    We need more attic ventilation, can you help us to figure out what type etc. mold (black, in color) is showing up on the underside of the roof sheating / what do we need to do once mold is treated? the house is a two story colonial built in 1994, attic square footage is 875feet, house is about 35 feet long and 25 feet wide with soffit vents 2″ wide x full length of soffit as well as a ridge vent full length of house, fiberglass mesh type under asphalt shingles/ no gable end venting?

    Do we add a power vent or just gable end vents and what size?

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