Proper way to re-roof?

Hi folks, I would like some opinions on this.
Shingles are old and need replacing, they want to go with steel, some say go right over shingles(I don’t think so):twisted:
some say strapping horizontal, I have heard that is wrong too. I have also heard remove shingles and go right over the sheeting no strapping needed. This is a friend of mine that asked my opinion so b4 I answer, I would like some others.
Thanks, Chuck

There are different schools of thought when installing metal shingles.

However, the manufacturer’s specs trump everything. Whatever they say goes.

Bill Mullen

I have yet to see a metal roof that wasn’t installed with purlins over existing shingles, but have never seen a metal roof installed directly on the deck as heat can be trapped. With purlins it breaths and remains cooler and allows for some expansion and contraction. I believe the use of purlins also dampens noise transmission during a rain storm. Some people do not like metal roofs because they are noisy during rains, however some find the sound soothing. As Bill mentioned the manufactures specs should be sought and followed.

For manufactures specs look at VICWEST SITE:


Those specs are only valid with VicWest products. Every manufacturer seems to put their unique spin on the requirements.

Bill Mullen

Yep! When all else fails, read the instructions.