Flashing tape for roof decking
We build houses for a Habitat for Humanity affiliate in a hurricane prone area along the Texas Gulf coast.
At a program on the FORTIFIED building certification, we saw something that intrigued us. They suggested taping the seams of the roof decking. This would prevent water damage in the event that the shingles were blown off in a wind storm. We started using such materials on the last few houses.
We finished decking and taping our latest house on Tuesday evening, but still can’t get our roofers here to “paper” the roof. On Wednesday, we had a small shower and the roof leaked rather badly. That evening, we received more rain and we had significant puddles in the house. We were not impressed.
So, we were using MFM flashing tape (Window Wrap PSX-20) – 6″ wide everywhere, except 9″ on the hips and valleys. We rolled it into place. The decking is foil-backed OSB, with the rough side up. I am thinking that is our problem. The tape does not stick well to the rough side (Same with the Dow Weathermate that we use around the windows. We get around that issue by making sure that we put the smooth side of the OSB sheathing outward).
Any suggestions on a different tape, technique, or material? At first, I thought about liquid applied flashing, but the horizontal joints on the decking between rafters are too squishy for that, I believe.
Steve Young, Lake Jackson, TX
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