# Insulating a Flat Roof



## Gremlyn (Dec 5, 2011)

My home was built in 1950 and has a flat roof. I am redoing part of the garage conversion, namely the laundry closet which was quite stupidly constructed, to provide a lot more storage and efficient use of the room we have. I decided I would also be able to put better lighting in and run some ethernet cabling through the house while I am at it, so I pulled down part of the ceiling as well. 

The previous DIYer used fiberglass sheets, and from what I read this is not a good choice for this application. BUT I am unsure what would be best... I have only opened up half the ceiling, but it would not be much work to open the rest if that would allow me to properly insulate this area.

Another point of confusion is if I should have any kind of moisture barrier in there as well?? I attached some pics, please ignore the obvious electrical code violations. I will be remedying those as well!


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## nealtw (Dec 6, 2011)

I don't see a lot wrong here. There should be a space between the insulation and the roof sheeting, I would use this batt insulation and add vapour barrier before the drywall and make sure there is venting on each side so air can freely move in and out under the sheeting.


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## Gremlyn (Dec 7, 2011)

Each of the spaces is sealed from the otherswhen the roof sheeting is in place, and there no vents to the outside either. From what I have been reading, with sealed spaces like that you want to take up as much room as possible with insulation.

I'm planning to paint the roof top with an elastomeric white paint as well for extra sun reflection after this remodel is done too. Just trying to make sure I am keeping the temperature inside what I want and not what the elements want!


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## nealtw (Dec 7, 2011)

CBD-176. Venting of Flat Roofs - IRC - NRC-CNRC

This write up explains it


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