# metal roofing over existing osb decking...please help



## peteb (Nov 23, 2014)

Wondering if anyone can advise on bad situation. My girlfriend has 1600 square 12 pitch roof. As old wood shake is being torn off im realizing big problem. Some sort of spray in foam was sprayed in by prior owners ....its sprayed in very thick(4 plus inches) and sealed at eaves running up to ridge. Plan was to repair any existing osb decking any go with a quality architectural shingle....with intake and ridge ventilattion. Problem is this foam is not easy to remove. My questions are. 1) Can i just strip to decking and go over it with some type of lighter metal roofing....concern is weight....it appears this foam crap has contributed to decay due to not allowing airflow. 2) Her budget is minimal.....thats why im doing it....if its not a bad idea to go with metal over existing osb decking with some airflow under metal will this help air out decking underneath. Any advice or words of wisdom here would be greatly appreciated.


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## roofermann (Jul 7, 2012)

Moved this to get it more visibility.:thumbup:


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## shazapple (Dec 3, 2010)

Any reasons why you are concerned with weight? If the roof structure is rafters, check if they are undersized. If it is trusses, typically they can handle it unless they have been altered. 

Depending on the condition of the OSB I would leave it. You will most likely have trouble getting it off due to the spray foam. I would install a breathable underlay over the existing OSB, then install wood strapping and your metal roofing.


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## vitone (Sep 27, 2014)

*Photos?*

How about some photos?


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