Friday, September 30, 2011

What up with the insulation on the roof decking??

The south side of my garage is in bad shape.  The north side is fine. Why is this?  I think I found out what is going on. The previous owner went insulation crazy on the inside of the garage. About half of the interior is sheetrocked with insulation. The other half is open studs.  The space between the rafters is insulated as well, but it may be causing some issues.  Most builders will agree that in order to insulate open rafter spaces, a styrofoam spacer should be used.  This allows air to flow from the soffit area, up the channel created by the spacer, then out the roof vents or ridge vents.  This garage has two issues.  First, it has insulation installed in the rafter spaces that is attached right to the bottom of the roof decking.  No air can flow and it's a great way to quickly ruin the roof. It get's extremely hot with the sun baking it and no air flow underneath. 
 In addition, there are not any soffit vents!  It's old, so that may explain it.  There are no roof or ridge vents either. The prior owner(s) chose to mount two powered fans in each gable end to pull the air out. This seems like a waste on energy to me and I'm not thrilled with the noise created.  So, bring on the plans!  I am ripping down the insulation and will install some soffit vents.  I will then reroof the structure and add some rectangular roof vents to let that air flow.  For insulation, I will put up a ceiling and insulate on top of that.  This will give me the airflow I need AND keep the space cool in the summer and warm in the winter. 

Do you have any ideas for this situation?  Any comments? If so, let me know.  I would be happy to discuss this with you.

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