Screw condensation

Byron Peterson
7/8/2015
I have been told that if your screws penetrate the roof sheeting, they will condensate and drip. This seems like it would only be a problem for places with severe temperature changes or attics without enough ventilation. Can somebody shed a little more light on the subject for me?
Dick Bus
7/8/2015
I have not heard of that. But you are right condensation will occur on most surfaces if there is not enough ventilation.
Todd Miller
Classic Products, Inc.
7/9/2015
Yes, I have seen this happen on screws and nails if there is inadequate ventilation in the attic space. The metal of the fasteners will conduct cold quickly, making it the coldest surface in the attic. If there is warm moist air in the attic that is not being vented out, it will condense on the fasteners.
Info @windowsonwashington.net
An informed customer is our best customer.
7/9/2015
We see it on nails in improperly vented attic as well. It isn't the screw/nail's fault. If you are getting condensation, the attic isn't vented sufficiently as Todd says.
Byron Peterson
7/10/2015
Will this happen if I attach the metal roof directly to the sheeting and have spray on foam under the sheeting with no air space?
Info @windowsonwashington.net
An informed customer is our best customer.
7/10/2015
If the spray foam is applied properly and in the proper thickness, it should not. The screws will be covered by the foam and therefore not exposed to the warm, moist air.

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