What is the best way to insulate a new roof from the exterior?

What is the best way to insulate a new roof from the exterior? #construction #green

The best way (and really the only way) to insulate the exterior of the roof is to install rigid foam on the top of the existing roof decking . Check what your local code minimum R-Value is and determine the foam thickness based from that. For a high performance home, it is recommended to increase the foam thickness to exceed the code minimum. Your builder or green rater can help you with this decision. A simple cost analysis can be run on different thicknesses and calculate a payback on each option. For more information : Read our tips "Three Ways to Make Your Roof More Energy Efficient ."

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