Join the MRA | Member Login
Find a Professional
  • Why Metal Roofing?
    • About MRA
    • Benefits of Metal Roofing
    • Compare Roofing Materials
    • Homeowner Testimonials
    • Inspiring Metal Roofing Projects
  • Homeowner Resources
    • Metal Roofing Buyers Guide
    • Resilient Housing Guide
    • Metal Roof Sustainability Guide
    • Above All Else You Need a New Roof eBook
    • MRA News
    • Member Provided Resources
    • 3rd Party Articles
    • Frequently Asked Questions
    • Preparing for Hurricane Season
  • Gallery
  • Visualizer
  • Ask The Experts
    • Energy Efficiency
    • Existing Metal Roof Questions
    • Installation
    • Is A Metal Roof Right For My House
    • Metal Roofing Benefits
    • Product Selection
    • Other
    • Archive
  • Find a Professional
Join the MRA Member Login
Sign Up Log In Add New Topic

TOPIC: Roofing over existing roof

adding a metal roof over existing asphalt

Return to Roofing over existing roof

Return to Archive

Return to Forum

This topic has been closed by the administrator. Comments are no longer accepted.
I'm putting Master-rib metal roofing over an existing asphalt shingle roof. What should the screw spacing be on both the edges and in the field.
Guest User

5/28/2004
Share
Or copy this URL: https://www.metalroofing.com/spirit/comment/2738/find/
30-pound felt is considered a moisture barrier rather than a vapor barrier. Vapor barriers, when installed, are usually behind the drywall in walls and ceilings for the purpose of keeping moisture from migrating into walls and attics. Felt, a moisture barrier, acts to protect the substrate beneath a roof from condensation. It can also help guard against roof leaks to some degree. In your case, the old shingles are in place to protect the decking. I personally am not fond of installing over asphalt shingles without an underlayment in between because expansion and contraction of the metal can cause abrasion to the metal as it rubs against the rough granular surface. In your case, though, your roof system is not designed to have a lot of movement so it is less of an issue. Just the same, my recommendation is to always have underlayment between the metal roofing and old shingles. I would look into what the installation procedures put out by the metal roofing manufacturer call for. Todd Miller
Todd Miller
Isaiah Industries, Inc.

5/29/2004
Share
Or copy this URL: https://www.metalroofing.com/spirit/comment/2739/find/
Screw spacing is based upon numerous things including the roofing profile and the metal thickness. This information must come from the manufacturer of your roofing material and will be based upon load tables which have been established through physical testing and engineering studies done on the roofing. Todd Miller
Todd Miller
Isaiah Industries, Inc.

5/29/2004
Share
Or copy this URL: https://www.metalroofing.com/spirit/comment/2740/find/
What should the spacing between the 1X4s be?
Guest User

5/29/2004
Share
Or copy this URL: https://www.metalroofing.com/spirit/comment/2741/find/
All information concerning fastening, spacing, etc. must come from the roofing manufacturer. These specifications vary from product to product based upon physical testing and engineering studies.
Guest User

5/29/2004
Share
Or copy this URL: https://www.metalroofing.com/spirit/comment/2742/find/
  • Previous
  • 1 -20
  • 21 -25
  • Next
  • About the MRA
    • Member Companies
    • Leadership
    • MRA News
  • For Professionals
    • Join the MRA
    • Industry Resources
    • Upcoming Events
  • Contact
  • Subscribe
©2018 Metal Roofing Alliance. All Rights Reserved. Privacy Policy Terms and Conditions