Replacing existing metal roof with new metal roof

Paul Kimball
I have a 7 year old metal roof installed straight over lath that has experienced many problems with rain leaks, particularly around dormers. After numerous fix attempts, the main culprits seem to be the incorrect flashing around the dormers. A well respected metal roofing installer has quoted me a tear off and installing roof grade OSB, felt, correct flashing, and new metal. He said he can save me some money by not removing the lath down to the rafters, but would leave it on and install the OSB directly over it. As long as he hits the rafters with the screws does this matter? The lath is really stout so I see where he can save a lot of labor time doing this. My rafters are what hey call stick built with the horizontal lath being 1 x 4s on 12 inch centers. In our area residential specs require metal to be installed on decking, but my main question is if it is ok to leave the lath on and deck over it.
Todd Miller
Isaiah Industries, Inc.
Actually, there's some pretty good energy efficiency achieved with this. If he can secure the new decking well and as long as he does not run into any permitting issues (I don't think he will), I think this is a good plan.
Eric Novotny
An informed customer is the Best Customer!
Curtiss, No reason the metal can't be put back on the purlins as long as it is permitted by the manufacturer. The decking does make it more walkable but there aren't a bunch more benefits to the decking.

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