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

Discussion Forum

Discussion Forum

Aluminum or Trex over flat roof

tomski | Posted in Tools for Home Building on April 7, 2004 05:12am

Hi All,

 Just finished tearing out an 8 year old rotted redwood roof deck that was laid on 2×4 redwood sleepers (laid flat) over a nearly flat rubber membrane roof. Of course the sleepers were toast but the 2×6 redwood deck also had a lot of mold between the 2x’s which I assume came from limited air circulation. I was thinking I would just replace the sleepers with pressure treated 2×4’s and cover it with Trex but I just found out that Trex will mold as well and  that Trex recommends sleeper heights of 3 and 1/2″ minimum for air circulation. Door and stairway threshold heights limit my options to put the sleepers on edge as recommended. The deck has only the slightest slope so there is standing water in spots after a rain.

I was wondering if anybody had experience with vinyl or aluminum deck boards laid right on a rubber membrane. I live in northern California where the summer temp can get over 100 degrees for days on end and  worry about the integrity of the membrane. Thanks in advance for any input.

Reply
  • X
  • facebook
  • linkedin
  • pinterest
  • email
  • add to favorites Log in or Sign up to save your favorite articles

Replies

  1. Stuart | Apr 07, 2004 05:47am | #1

    I have a similar situation at my house and I've been thinking about using a fiberglass grating product made by Strongwell.  It's a series of T-shaped fiberglass slats assembled into flat panels of various sizes; originally they were built for use in animal pens, to keep the animals up off the concrete floor, but they're now also used for a variety of industrial applications, like catwalks in factories and such.  I think it would be great for a boat dock as well.  They also have another product that is a series of flat planks that snap together that looks interesting.

    You can see what I'm talking about at http://www.strongwell.com/ProductsMenu.html.  Look under the Pultruded Fiberglass Products menu, at Grating and Flooring, and Decking Systems.

    I first saw this stuff back in the 1970s when I worked at one of their manufacturing plants one summer during college, so it's been around for a while, but I don't know if it's been used much if at all in residential applications.

    1. tomski | Apr 07, 2004 07:01pm | #2

      Thanks Stuart. I'll check it out.

      1. User avater
        Homewright | Apr 07, 2004 09:24pm | #3

        A partner and I once did a deck over roof situation where we built the deck in removable segments for cleaning purposes.  The sections were about 6' x 6' and weighed enough not to blow away in a heavy wind but not prohibitively heavy to lift and set against something for a good hose down.  You might also consider using Gacodeck to finish the deck area.  It's a paint on product with ground up walnut shells for traction.  It comes in numerous colors and from what I've seen, might be around when the cockroaches are running things.  Just a couple thoughts on options....

  2. csnow | Apr 07, 2004 09:51pm | #4

    I wonder if the mold on the deckboards came from water wicking up through the sleepers.  You would think an open deck with sun exposure would dry between soakings, and keep the mold away.

    It would be better to use a less absorbant material than wood for the sleepers.

    Trex is less absorbant than wood, but several other plastic decking products are even better in this regard.

  3. BMan | Apr 07, 2004 10:31pm | #5

    How about stone or concrete pavers? If the joists can support an extra 10psf or so, check out precast concrete pavers, specifically made for roof decks and plazas. Some manufacturers include Hanover or Wausau. The pavers are typically 24" square, with dimples on the bottom to maintain drainage below the paver. Install over a slip sheet to prevent wear on the rubber membrane. There are also pedestal systems available to raise the pavers up off the roof deck.

    1. tomski | Apr 08, 2004 04:55am | #6

      Thanks for the input. I checked out their web site and unfortunately I don't think my joists are beefy enough. Any idea if there a "fake" lightweight concrete that might work? Maybe even something that can be "stamped" to give a more custom look?

      1. BMan | Apr 08, 2004 02:43pm | #7

        Tom,

        I don't know of any fake or stamped products. I think anything thinner than 1-1/2"-2" would just snap. What size joists, span, spacing do you have? Typically the joist is deeper than needed to accommodate the required depth of insulation, not the structural condition.

        There are also finished membranes, like Deck rite or something. They advertise in Fine Homebuilding. I have never used them. If redwood rotted, I would look for a more durable material than wood.

        Good luck.

        Brian

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Video Shorts

Categories

  • Business
  • Code Questions
  • Construction Techniques
  • Energy, Heating & Insulation
  • General Discussion
  • Help/Work Wanted
  • Photo Gallery
  • Reader Classified
  • Tools for Home Building

Discussion Forum

Recent Posts and Replies

  • |
  • |
  • |
  • |
  • |
  • |
View More Create Post

Up Next

Video Shorts

Featured Story

Affordable Scans, Accurate Plans

Hover's smartphone app offers an easier way to get precise 3D scans.

Featured Video

Video: Build a Fireplace, Brick by Brick

Watch mason Mike Mehaffey construct a traditional-style fireplace that burns well and meets current building codes.

Related Stories

  • Podcast Episode 686: Brick Steps, Ground-Source Heat Pumps, and Greenhouses in Nova Scotia
  • FHB Podcast Segment: Efficient HVAC for a New Build
  • Affordable Scans, Accurate Plans
  • FHB Summit 2025 — Design, Build, Business

Highlights

Fine Homebuilding All Access
Fine Homebuilding Podcast
Tool Tech
Plus, get an extra 20% off with code GIFT20

"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.

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

Fine Homebuilding Magazine

  • Issue 331 - June 2025
    • A More Resilient Roof
    • Tool Test: You Need a Drywall Sander
    • Ducted vs. Ductless Heat Pumps
  • Issue 330 - April/May 2025
    • Deck Details for Durability
    • FAQs on HPWHs
    • 10 Tips for a Long-Lasting Paint Job
  • Issue 329 - Feb/Mar 2025
    • Smart Foundation for a Small Addition
    • A Kominka Comes West
    • Making Small Kitchens Work
  • Issue 328 - Dec/Jan 2024
    • How a Pro Replaces Columns
    • Passive House 3.0
    • Tool Test: Compact Line Lasers
  • Issue 327 - November 2024
    • Repairing Damaged Walls and Ceilings
    • Plumbing Protection
    • Talking Shop

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 70%

Subscribe

Enjoy unlimited access to Fine Homebuilding. Join Now

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