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

Sealing around vents

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.
We are wanting to put a metal roof over our existing asphalt shingle roof. One outstanding question is the best way to seal the various vents that poke through the roof. Is silicon caulk the preferred sealant? Also, we are wondering if it would be better to pull the asphalt shingles off, put new 30# felt down, and then put the metal roof on top of that, rather than over the old asphalt shingles. Seems like that over asphalt there could be problems of bending the metal when walking on it. Thanks, Rod
Guest User

5/4/2003
Share
Or copy this URL: https://www.metalroofing.com/spirit/comment/1833/find/
For pipe penetrations, there are a variety of flashings available which can be used with most stles of metal roofing. These flashings typically have a rubber boot which seals around the pipe and then a metal frame of some sort which is flashed into the roofing. It is also possible to custom make pipe flashings from metal which matches the roof. It is always best to follow the manufacturer's instructions as to handle penetrations and other flashings. As for attic vents, most styles of those can also be used. Again, the exact installation method depends upon the profile of roofing you choose. Make sure you have full instructions from the roofing manufacturer as well as available phone support before emnarking on this, or use a qualified and experienced professional installer. Many metal roofs are designed for going over existing shingles. This is due to the low weight of metal roofing and also due to the design of the products. Some styles of metal roofing can also be installed on top of lathe which would be installed over the old shingles. Again, different metal roof profiles have different requirements. Once you choose the metal roof you're going to install, verify proper installation methods with the manufacturer of the roofing. Good luck. Contact us if additional questions come up. Todd Miller
Todd Miller
Isaiah Industries, Inc.

5/4/2003
Share
Or copy this URL: https://www.metalroofing.com/spirit/comment/1834/find/
  • 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