Flash and batt closed cell with initial flash of open cell
Ok. I'm building an addition. This is in Cape Ann MA. North of Boston. North facing roof 4 pitch that ends in a sidewall. It is a hot roof. it was flashed with 3" of closed cell foam this past october. The foam failed and is now being removed. It pulled away from the roof sheathing and at the rafter tails. Not everywhere, but there Is no Pattern to where it shrank. Some places it shrank 1/8" others 3/4". The installers want to now flash the rafter tails with open cell because they think the sheathing is cold and the open cell will adhere. They will then go over the open cell with closed cell. They just want to do this at the rafter tail and no where else. I attempted air sealing at the outside with caulking and vycor on the sheathing to rafter tails. Is flashing with open cell and then covering with closed cell ok? Just seems weird to me. The owner claimed this is common practice with cold surfaces. Thanks, Nick.
Posted Fri, 02/22/2013 - 14:15
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