Join the MRA | Member Login
Find a Professional
  • Why Metal Roofing?
    • Benefits of Metal Roofing
    • Compare Roofing Materials
    • Homeowner Testimonials
    • Inspiring Metal Roofing Projects
  • Homeowner Resources
    • MRA Roofing Buyer’s Guide
    • Resilient Housing Guide
    • Metal Roof Sustainability Guide
    • Metal Roofing News
    • Member Resources and News
    • Industry Partners
    • Frequently Asked Questions
    • Preparing for Hurricane Season
    • Regional Considerations
  • 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: Installation

Proper Installation of metal roof

Return to Installation

Return to Forum

I am having to replace my roof. I currently have a 20 yr old composition roof. It is made up of 30 yr composition over felt. The decking is tongue and groove and is in good shape. I am considering installing a metal roof over the current roof. I have been told that the metal can be installed directly over the old shingles with no underlayment or vapor barrier. What would be the proper way to do this. I am having a contractor do the installation. Thanks for any help you can give me.
Richard Phillips

10/1/2013
Share
Or copy this URL: https://www.metalroofing.com/spirit/comment/18861/find/
As long as you have good attic ventilation, you do not need a vapor barrier. However, I feel that you do need underlayment even for re-roofing. This is to separate between the rough surfaced old shingles and the back of the new metal roof. Also, I feel that it is required by International Building Code (though not all may interpret the IBC that way). Todd Miller
Todd Miller
Isaiah Industries, Inc.

10/1/2013
Share
Or copy this URL: https://www.metalroofing.com/spirit/comment/18862/find/
Is the attic ventilated to begin with or is it an insulated roof deck? Gotta have a slip layer at a minimum and I can't imagine why anyone wouldn't recommend one given the fractional cost. Eric Novotny
Eric Novotny
An informed customer is the Best Customer!

10/2/2013
Share
Or copy this URL: https://www.metalroofing.com/spirit/comment/18863/find/

If you would like to reply to this thread, please log in. If you do not have an Ask the Experts forum user account, create one here.

  • About the MRA
    • Member Companies
    • Leadership
    • MRA News
  • For Professionals
    • Join the MRA
    • Industry Resources
  • Contact
  • Subscribe
©2023 Metal Roofing Alliance. All Rights Reserved. Privacy Policy Terms and Conditions