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
How-To

Is There a Chance For Condensation in Double-Stud Walls?

By Scott Gibson Issue 236 - June/July 2013
  • X
  • facebook
  • linkedin
  • pinterest
  • email
  • add to favorites Log in or Sign up to save your favorite articles
Dan Thornton

Q:

Michael Roland is designing a new house and is trying to choose the right wall assembly. It’s down to a choice between a double-stud wall with either batt or loose-fill insulation, or a more conventional stud wall wrapped in a layer of rigid-foam insulation.

“Using exterior rigid foam solves thermal bridging and prevents condensation within the batts in the wall cavity,” he writes in a post at the Green Building Advisor Q&A forum. “Double-wall construction also solves thermal bridging, but what about the dew point within the batts? Won’t there be a condensation problem?”

A:

Don’t worry about condensation in batts, writes Dana Dorsett, because it won’t occur. “Condensation doesn’t happen in batts,” he says. “Because batts are extremely vapor permeable, and because low- to mid-density batts are so air permeable, whenever the coldest surface of the cavity framing reaches the dew point of the entrained air in the cavity, the moisture condenses on that surface, not in the fiber itself.” While the condensing surface is picking up moisture, Dorsett adds, “at any other point within the batts, the fiber temperature is above that temperature, so no condensation occurs.”

“If [the condensing surface] is a hygroscopic material such as OSB sheathing, moisture also doesn’t condense, but instead absorbs into the material, never achieving a true liquid state unless there is so much moisture entering the cavity from air leaks that the OSB saturates,” Dorsett writes.

The real risk is that OSB sheathing will rot. According to Jesse Thompson, an architect in Portland, Maine, “A double-stud wall with any type of batt insulation is a high-risk wall system in a cold climate, due to the cold-sheathing issue.”

There are ways of reducing the risk of decay in sheathing, as several contributors point out. One is to use a hygroscopic insulation such as cotton batting or cellulose, which can absorb moisture. “The insulation in contact with the cold surface will absorb moisture, which results in lower moisture accumulation in the sheathing,” Dorsett writes. “Cellulose can take on quite a bit of moisture before saturating and losing R-value, and can store, then rerelease, the moisture as conditions change.”

Thompson seconds the advice. With double-stud wall construction, he suggests careful air-sealing and aiming for blower-door results of less than 1.5 air changes per hour at 50 pascals of pressure.

Another strategy is to use plywood or diagonal-board sheathing instead of OSB, along with a ventilated rain-screen gap between the siding and the sheathing, Fine Homebuilding senior editor Martin Holladay says. Both boards and plywood are less susceptible to mold and rot than OSB. That’s because OSB is made from fast-growing plantation-raised lumber that has a comparatively high proportion of sapwood. Sapwood’s high sugar content causes Joe Lstiburek of Building Science Corp. to refer to OSB as “the Spam of mold food.”

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.

Respirator Mask

A full-face respirator prevents fog up and is more comfortable than constantly replacing particle makes that get fouled or sweaty and is ideal for the pro installer.
Buy at Amazon

Caulking Gun

It's important for any insulator to have a good caulking gun for air sealing or adhesives, and this one features a revolving frame that makes orienting the tip a breeze.
Buy at Amazon

Nitrile Work Gloves

Do yourself a favor and protect your hands while you work. These lightweight, breathable work gloves will keep your hands safe while cutting and fitting.
Buy at Amazon

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
×

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

New Feature

Fine Homebuilding Forums

Ask questions, offer advice, and share your work

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

View Comments

  1. user-7498225 | Sep 21, 2019 09:10pm | #1

    How is a double stud wall any different from a normal wall with Batts in it (1st reference vs. 2nd reference in the article). If it is filled with the same insulation.

    In the first reference we go from a don't worry about it mentality compared to the second reference of a oh crap this is a huge deal!

    Isn't a double stud wall technically the same as a normal wall minus the thermal bridge of a stud.

    Please sort this confusion out for me

    1. JonBlakemore | Nov 01, 2021 10:56am | #2

      Hammer35,

      Since the double stud walls have so much more R value, your sheathing will be colder, thus below the dew point.

      If you have a temp difference of 70 degrees, a 2x4 bay with no insulation will have very warm sheathing due to the massive heat loss from the interior through the wall. No rot, but very inefficient. If you add an R13 batt, your heat loss goes down but you will probably still have warm sheathing. If you have a deep cavity with R60 insulation, you will have very little heat loss so the OSB will be almost the same temp as the outside air.

Log in or create an account to post a comment.

Sign up Log in

Become a member and get full access to FineHomebuilding.com

Up Next

Video Shorts

Featured Story

A New Approach for Millwork Finishes

The LED-cure products from LED Coating Solutions offer a fast-curing, zero-VOC finish that works well for trim and cabinetry in small shop settings.

Featured Video

Builder’s Advocate: An Interview With Viewrail

Learn more about affordable, modern floating stairs, from design to manufacturing to installation.

Related Stories

  • A Practical Approach to Exterior Insulation
  • Making and Installing Wood Wall Paneling
  • FHB Podcast Segment: Designing and Building an Efficient Slab-On-Grade Home
  • Putting Drywall Sanders to the Test: Power, Precision, and Dust Control

Discussion Forum

Recent Posts and Replies

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

Highlights

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

Video

View All Videos
  • FHB Podcast Segment: Designing and Building an Efficient Slab-On-Grade Home
  • FHB Podcast Segment: Insulating and Air-Sealing Behind a Masonry Wall in a Remodel
  • FHB Podcast Segment: Insulating the Roof of a Small Balloon-Framed House
  • FHB Podcast Segment: Old Home Insulation Troubles - How to Find the Right Contractor
View All

Insulation

View All Insulation Articles
  • Makeshift Foam Tip for Tight Spots
  • Insulation Shield for Wafer Lights
  • Ranch Redux
View All Insulation Articles

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 81%

Subscribe

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