Cool roof on a rigid foam retrofit
I have been doing extensive research prior to begining my remodel on my new home. I would like to get some advice on how to aproach my remodel.
The home is a 2600 sq ft contemporary style house. The majoroty of the roof is an unvented catherdral roof assembly. It is a simpole gable roof, although the North face is much steeper. It currently has an aging asphalt roof that will need replacing soon. I am planning a PV array instalation and need advice on what sort of assembly would be the best combination.
Based on research I know that a metal roof is most likely my best option for longevity and performance with the PV array. I saw a few rigid foam retrofit roof details on GBA. These were hot roof assemblies. However, I was curious if anyone had run across a cool roof assembly with a rigid foam retrofit? See the attached image for specifics. The rigid foam has 1×3 battens installed over the top with a pre-galvinized continuous vent installed at the eave.Over this goes the new sheathing, then the ice and water shield. Finally the standing metal seam would go on. There would be a ridge vent installed along the top.
I would like to know if there are any benifits to this type of assembly. I realize that the venting would certainly aid in cooling the metal, however, in seaching for a cost effective solution, I am unsure if any benifits would be marginal and not worth the extra expense. I look foward to any insite on this.
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