FHB Logo Facebook LinkedIn Email Pinterest Twitter X Instagram Tiktok YouTube Plus Icon Close Icon Navigation Search Icon Navigation Search Icon Arrow Down Icon Video Guide Icon Article Guide Icon Modal Close Icon Guide Search Icon Skip to content
Subscribe
Log In
  • How-To
  • Design
  • Tools & Materials
  • Restoration
  • Videos
  • Blogs
  • Forum
  • Magazine
  • Members
  • FHB House
  • Podcast
Log In

Fine Homebuilding Project Guides

Roofing

Guide Home
  • Tools and Materials
  • Roof Replacement and Reroofing
  • Roof Ventilation
  • Waterproofing
  • Installing Asphalt Shingles
  • Installing Other Types of Roofs
  • Roof Maintenance and Repair
Ask the Experts

Best Deck for a Steel Roof

For a metal roof, install solid decking such as OSB or plywood.

By Todd E. Miller Issue 315 - June 2023
  • X
  • facebook
  • linkedin
  • pinterest
  • email
  • add to favorites Log in or Sign up to save your favorite articles

I’m in the process of building a 30×40, stick-framed, two-story shop. The roof will be made of engineered trusses installed 24 in. on center and have a 4:12 pitch. My question has to do with the roof decking. I’m going to install a ribbed steel roof but haven’t decided whether to use hidden or exposed fasteners. To add strength and reduce the noise caused by the rain, I would like to install the steel over 7/16-in. OSB decking instead of purlins. However, I’ve been told that installing steel over OSB could cause oil-canning and might even void the warranty on the steel. Is this true? Also, what type of underlayment works best with steel?

—Curtis Eriksen, Eden Prairie, Minn.

Todd E. Miller, president of Isaiah Industries, replies: For both exposed-fastener panels and hidden-fastener standing-seam panels, I prefer installations over solid decking such as OSB or plywood. This is a best practice generally followed by industry leaders. Metal-roof installations over solid decking are easier to walk and generally more friendly to the roof installer. They also tend to be more wind resistant and less prone to condensation.

Metal roofs installed on purlins over smaller conditioned spaces are likely to develop condensation unless the structure is extremely well vented and includes a vapor barrier built into the ceiling and walls. Without a vapor barrier, warm moist air trying to drive out of the structure hits the cool back surface of the metal and condenses quickly. I have seen many disappointed homeowners and builders dealing with this situation.

As to your question about oil-canning—or ripples in the installed metal roof panels— this can develop when the substrate beneath the panels is not flat. It can happen with installations over both purlins and solid decking. The key is to have a flat surface for the metal panels to be installed over. Oil-canning can also be caused by improper fastening, and sometimes it can be integral to the metal panels themselves.

I am unaware of any metal roof products that would have their warranties voided for installation over solid decking, but always check with your manufacturer and follow their specifications as well as applicable local building codes. In fact, most manufacturers prefer, if not require, solid decking. Metal shingles, another option in the wide world of metal roofing, typically all require solid decking.

When it comes to underlayment, depending upon your location you may be required to have a peel-and-stick membrane around the building perimeter. Beyond that, though, most manufacturers are partial to the use of “premium grade” synthetic underlayments. The premium products can best be identified by a weight of 35 lb. or more per 1000-sq.-ft. roll. Most manufacturers of peel-and-stick advise against installing their products on the entire roof surface. Doing so will seal the structure up like a terrarium and substantially increase the need for good ventilation.

From Fine Homebuilding #315


RELATED STORIES

  • Snap-Lock Standing-Seam Metal Roof Installation
  • Oil-Canning Deck Fascia
  • Adding a Vented Roof Deck

Fine Homebuilding Recommended Products

Fine Homebuilding receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

Roofing Gun

This lightweight, pneumatic roofing nailer is capable of driving ¾-in to 1¾-in coil roofing nails and has a depth adjustment wheel to dial in nailing depth on the various shingle types you're likely to encounter.
Buy at Amazon

Metal Connector Nailer

This time-saving tool is the fastest way to install hardware. The tip is designed to locate the hole in the hardware, then all you have to do is pull the trigger.
Buy at Amazon

Ladder Stand Off

Stability is key when working off a ladder or accessing the roof, and this lightweight aluminum stand-off makes any extension ladder safer and more comfortable to use.
Buy at Amazon
Previous: How to Craft a Copper Roof Next: Guide to Low-Slope Roofing

Guide

Roofing

Chapter

Installing Other Types of Roofs

Sign up for eletters today and get the latest how-to from Fine Homebuilding, plus special offers.

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

View Comments

  1. user-4435907 | May 03, 2023 09:02pm | #1

    I would bump the thickness of the OSB to 5/8" thick minimum. Hard to get a bite in 7/16" OSB without stripping out in the OSB.

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Roofing

Roofing

A complete resource that includes the best materials and the right techniques to build a sturdy, leak-free, attractive roof on any house

View Project Guide

View All Project Guides »

Become a member and get unlimited site access, including the Roofing Project Guide.

Start Free Trial

Tools and Materials
  • Roof Coverings
  • Roofing Materials
  • Power Tools
  • Handy Helpers
  • Staging and Ladders
  • Safety Equipment
Roof Replacement and Reroofing
  • Preparing the Old Roof
  • Sheathing
  • Installing the New Roof
Roof Ventilation
  • Venting Basics
  • Installation
Waterproofing
  • Underlayment
  • Drip Edge
  • Flashing Adjoining Walls
  • Dormer and Skylight Flashing
  • Chimney Flashing
  • Vent Flashing
  • Gutters
Installing Asphalt Shingles
  • Calculating Shingles
  • Layout
  • Installation
  • Valleys
Installing Other Types of Roofs
  • Cedar Shingles
  • Metal
  • Low-Slope Roofs
  • Slate and Tile
Roof Maintenance and Repair
  • Assessing the Problem
  • Repairing Asphalt-Shingle Roofs
  • Other Roofing Repairs

Fine Home Building

Newsletter Sign-up

  • Fine Homebuilding

    Home building tips, offers, and expert advice in your inbox.

  • Green Building Advisor

    Building science and energy efficiency advice, plus special offers, in your inbox.

  • Old House Journal

    Repair, renovation, and restoration tips, plus special offers, in your inbox.

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters

Follow

  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X
  • Fine Homebuilding

    Dig into cutting-edge approaches and decades of proven solutions with total access to our experts and tradespeople.

    Start Free Trial Now
    • Facebook
    • Instagram
    • X
    • LinkedIn
  • GBA Prime

    Get instant access to the latest developments in green building, research, and reports from the field.

    Start Free Trial Now
    • Facebook
    • YouTube
  • Old House Journal

    Learn how to restore, repair, update, and decorate your home.

    Subscribe Now
    • Facebook
    • Instagram
    • X

Membership & Magazine

  • Online Archive
  • Start Free Trial
  • Magazine Subscription
  • Magazine Renewal
  • Gift a Subscription
  • Customer Support
  • Privacy Preferences
  • About
  • Contact
  • Advertise
  • Careers
  • Terms of Use
  • Site Map
  • Do not sell or share my information
  • Privacy Policy
  • Accessibility
  • California Privacy Rights

© 2025 Active Interest Media. All rights reserved.

Fine Homebuilding receives a commission for items purchased through links on this site, including Amazon Associates and other affiliate advertising programs.

  • Home Group
  • Antique Trader
  • Arts & Crafts Homes
  • Bank Note Reporter
  • Cabin Life
  • Cuisine at Home
  • Fine Gardening
  • Fine Woodworking
  • Green Building Advisor
  • Garden Gate
  • Horticulture
  • Keep Craft Alive
  • Log Home Living
  • Military Trader/Vehicles
  • Numismatic News
  • Numismaster
  • Old Cars Weekly
  • Old House Journal
  • Period Homes
  • Popular Woodworking
  • Script
  • ShopNotes
  • Sports Collectors Digest
  • Threads
  • Timber Home Living
  • Traditional Building
  • Woodsmith
  • World Coin News
  • Writer's Digest
Active Interest Media logo
X
X
This is a dialog window which overlays the main content of the page. The modal window is a 'site map' of the most critical areas of the site. Pressing the Escape (ESC) button will close the modal and bring you back to where you were on the page.

Main Menu

  • How-To
  • Design
  • Tools & Materials
  • Video
  • Blogs
  • Forum
  • Project Guides
  • Reader Projects
  • Magazine
  • Members
  • FHB House

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Podcasts

  • FHB Podcast
  • ProTalk

Webinars

  • Upcoming and On-Demand

Popular Topics

  • Kitchens
  • Business
  • Bedrooms
  • Roofs
  • Architecture and Design
  • Green Building
  • Decks
  • Framing
  • Safety
  • Remodeling
  • Bathrooms
  • Windows
  • Tilework
  • Ceilings
  • HVAC

Magazine

  • Current Issue
  • Past Issues
  • Magazine Index
  • Subscribe
  • Online Archive
  • Author Guidelines

All Access

  • Member Home
  • Start Free Trial
  • Gift Membership

Online Learning

  • Courses
  • Project Guides
  • Reader Projects
  • Podcast

More

  • FHB Ambassadors
  • FHB House
  • Customer Support

Account

  • Log In
  • Join

Newsletter

Get home building tips, offers, and expert advice in your inbox

Signing you up...

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
See all newsletters
See all newsletters

Follow

  • X
  • YouTube
  • instagram
  • facebook
  • pinterest
  • Tiktok

Join All Access

Become a member and get instant access to thousands of videos, how-tos, tool reviews, and design features.

Start Your Free Trial

Subscribe

FHB Magazine

Start your subscription today and save up to 81%

Subscribe

This is your last free article.

Don't miss another expert tip or technique from building pros. Start your free trial today.

Start your FREE trial

Already a member? Log in

We hope you’ve enjoyed your free articles. To keep reading, become a member today.

Get complete site access to expert advice, how-to videos, Code Check, and more, plus the print magazine.

Start your FREE trial

Already a member? Log in

Privacy Policy Update

We use cookies, pixels, script and other tracking technologies to analyze and improve our service, to improve and personalize content, and for advertising to you. We also share information about your use of our site with third-party social media, advertising and analytics partners. You can view our Privacy Policy here and our Terms of Use here.

Cookies

Analytics

These cookies help us track site metrics to improve our sites and provide a better user experience.

Advertising/Social Media

These cookies are used to serve advertisements aligned with your interests.

Essential

These cookies are required to provide basic functions like page navigation and access to secure areas of the website.

Delete My Data

Delete all cookies and associated data