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

Flooring my attic

George94 | Posted in General Discussion on August 1, 2020 02:27pm

I’m thinking of putting some plywood in my attic to add a bit of storage space and for the kids to use from time to time, I was wondering if I could get your input on the best way to do this. I live in the SF bay area, the house was built in 1940 and has plaster ceilings. The space I’m thinking of is on top of their current bedroom and looks like this:

https://drive.google.com/file/d/1aNHWkm8no80NHlN-gTNMtPMFLKdw1WZj/view?usp=sharing

The space is about 16′ by 13′. The joists are 2×4″ with 16″ centers, and there is a 2×4″ sistered to a 1×8″ running perpendicular to the joists for support. The edges of this space are roughly aligned with the walls of the bedroom. The insulation is about 10-12″ thick. There is a pull down ladder in the hallway just to the left of this picture. I was thinking of screwing down some 2x8s perpendicular to the joists on 16″ centers and then laying 1/2″ plywood on top of that. Though getting 16′ long 2x8s into the attic would be a challenge… What do you think?

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

Replies

  1. Frankie | Aug 01, 2020 04:16pm | #1

    Pic didn't come though.

    "Screwing down 2x8s perpendicular to the joists..." - you mean on top of the joists, so they run the length of the attic? ABSOLUTELY NOT !!!!! (assuming existing 2x4 joists run the width).

    Do the 2x4s run full width of the attic or do they butt/ overlap at a center supporting wall below? Is that where the 1xx8 is?

    If just for light storage, sister existing 2x4s using 2x6s or 2x8s, face to face of the 2x4s. Use lots of Simpson screws/ nails and construction adhesive. Nails/ screws need to be protrude opposite side of joists by 1/2" minimum so use min 3 1/2" screws.

    https://www.strongtie.com/strongdrive_exteriorwoodscrews/sds_screw/p/strong-drive-sds-heavy-duty-connector-screw

    Sistering may have to alternate sides of each 2x4 joist, depending on existing framing conditions.

    Glue and screw sheathing also.

    http://www.grabberman.com/Media/TechnicalData/Product282.pdf

    Frankie

    1. George94 | Aug 01, 2020 04:45pm | #2

      Thanks for the info. Here's a link to the photo:
      https://drive.google.com/file/d/1aNHWkm8no80NHlN-gTNMtPMFLKdw1WZj/view?usp=sharing

      The 2x4s run from one wall to the other. The supporting 2x4 & 1x8 is in the middle of the supporting walls, lying on top and perpendicular to the 2x4s with no supporting wall underneath it. Sistering the existing 2x4s is tricky because of the 2x4 and 1x8 lying across the middle of the joists.

  2. User avater
    unclemike42 | Aug 02, 2020 06:48am | #3

    The 2x4 ceiling joists are not sized to support lots of load.

    but if you want to put in a floor, and keep the insulation below, I would make up some open top plywood boxes, and sit them upside down on the joists. You can make each one a couple feet on a side, and a foot deep. glue and screw or nail them together.

    you can cut half inch deep slots in the box sides where they sit on the joists to keep the orientation and then tack a 1x around the perimeter to keep it all together.

    Will have to cut a slot in the insulation to let the sides of the boxes reach the top of the existing joists.

    these will be fairly easy to take up that folding stairway.

    but you do have to think about what this will do in the next earthquake.

    If it was me, I would leave this space as it is and get a shed for the back yard.

  3. mcmatthelake | Aug 02, 2020 07:59am | #4

    Are you sure those are 2x4’s? I am not understanding how the insulation could be “10-12 inches thick” if it is only a single 2x4? Could they have added the 2x4 on top of the joist in order to increase the thickness of the insulation? If in fact there is more structure - joists large enough to accommodate 10 to 12” of insulation, then I think you could do the attic easily. As far as plywood, I would steer clear of it. I would recommend 1x 6’s or 8’s and space them apart 3/16 to 1/4 inch. You can precut them and assemble with screws in the attic- wrestling plywood up to the second floor and then up to the attic via a drop down ladder will wear you out. If you use spruce 1x6’s you will have a nice splinter free floor. Be sure to identify any NM wire run and make sure that you mark it’s location so you do not injure it, but also if you ever need to come back and access it.

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

FHB Podcast Segment: Patching Drywall Near a Shower

Learn how to patch drywall above a fiberglass shower without totally redoing everything.

Featured Video

Micro-Adjust Deck-Baluster Spacing for an Eye-Deceiving Layout

No math, no measuring—just a simple jig made from an elastic band is all you need to lay out a good-looking deck railing.

Related Stories

  • A Summer Retreat Preserved in the Catskill Mountains
  • Fine Homebuilding Issue #332 Online Highlights
  • The Trump Administration Wants to Eliminate the Energy Star Program
  • Podcast Episode 685: Patching Drywall, Adding Air Barriers, and Rotted Walls

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