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

rotten subfloor/joists

Pascanale | Posted in Construction Techniques on March 19, 2009 02:59am

I’ve discovered a rotten rim joist and several ends of floor joists when R&R an entrance door. I suspected as much since the floor was slightly sunken inside the home. The failure occurred since the mudsill is essentially below grade, nothing was really done in terms of moisture barrier and the lumber was not PTL. Furthermore, a concrete slab walk up to the door was poured directly against the foil-backed polyiso- insulation board that was placed against the foundation block. The joists are 2×10 and are above the slab only 4″ putting the mudsill at approximately 6″ down.

So, the questions are:

– How can I detail this better to prevent it from happening again aside from PTL and something similar to ice guard used on roofs. I dont’ know the product’s name but I used it for around windows to flash the rough sill rather fabricating a metal tray.

– I might be inclined to add a french drain while the slab is gone (expecting to demo it and replace to gain access to the rim joist).

– There may be still another source of the water intrusion since the subfloor was rotted out, too, and I believe that’s too high for ground water to have rotted it by capilary action through the joists at the contact point. That’s another issue since I’m sure the water primarily came in from the ground. The worst area is at the door where the slab is but there is further evidence several feet away where the earth and mulch are up against the house.

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

Replies

  1. Houghton123 | Mar 19, 2009 05:34am | #1

    A drawing would help with responses.

    French drains, yes, but you need to deal with water intrusion, since it's the water held against the wood that causes the rot.

    Our old house has had a lot of poor designs too - and I struggle constantly with redesign to reduce problems.

    1. Pascanale | Mar 19, 2009 03:45pm | #4

      The water intrusion is definitely the focus--the french drain is just a means to carry away surface water. First, besides identifying any other source of water (potentially overflowing gutter/downspout above), I want to have a better detail of for covering the rim joist/mudsill and first course of block. That's why I mention a covering of these three surfaces in one pass with a vertical membrane of something comparable to iceguard used on roofs. I know there's something out there used for windows on new installs and it comes in various width rolls. One type can even be stretched to flash around inside corners similar to neoprene roofing. Ideally, 2-3 feet would do it.

      Does this material ring a bell?

      Its been suggested to regrade the yard properly and I knew that but anticipate resistance from the home owner. That's why I want a detailing of how to combat the bad situation as best as possible and leave the final decision up to them. Of course the grade issue still needs to be stated since the present condition is part of the problem. The original issue is the addition was built one course short of the existing which doesn't have this problem.

      1. cargin | Mar 19, 2009 04:13pm | #6

        pascanale

        You could try this site

        http://www.protectowrap.com/products/waterproof.php

        Big box store have peel and stick bitumen roofing products like this Protecto seal 45. It's about 3 times as thick as I&W. 1 Sq is $90. Or 3' x 33' roll.

        http://www.protectowrap.com/products/roofing.php

        Rich

        1. Pascanale | Mar 19, 2009 04:58pm | #7

          That's it! I used the narrower version on windows but couldn't remember where I got it or the name. Thx

  2. john7g | Mar 19, 2009 02:52pm | #2

    Start with regrading to get the soil level below the mudsill.  Do what it takes which may include regrading the whole yard.  Even if you put the french drain in, the soil will still hold moisture as well as make an easy entrance for any bugs you might have there (ie termites). 

    Once you're repaired your rot and before you install the door you need to flash the whole area under where the door threshold will go. 

    1. Pascanale | Mar 19, 2009 03:33pm | #3

      John, I've considered regrading because that's what should have been done originally and yes, it will entail a large part of the yard since its pretty flat leading up to the the problem area. As for the flashing material, I'd like to use something other than what was originally done--coil stock. I'd like to use the comparable appropriate material as what's now suggested for windows on new installs, something similar to iceguard used on roofs. I envision using this from the top of the rim joist and wide enough to finish in one width, to below grade, at least covering the first course of block. Ideally, this seal or, at least, overlap onto whatever sparging was applied onto the block foundation. Any thoughts on that?

      1. john7g | Mar 19, 2009 04:00pm | #5

        The Ice & Water shield would work but so doe scoil stock when the conditions aren't stacked against it.  But most important is the regrade.  Have you checked the rmainder of th ehosue perimieter?  If they screwed it up at the door, there's probably other places. 

        1. Pascanale | Mar 19, 2009 05:03pm | #8

          This part was an addition with the block one course shorter than the rest. The rest of the house is therefore out of harm's way. Why they built the this addition shorter isn't immediately apparent. I'm thinking through this now. The floor in the addition is lower but not by a full block and I don't believe the joists are different in depth to account for this either. Explaining this is all reverse engineering which only soothes one's curiousity. Interestingly, I didn't see any termite barrier under the mud sill either. I'm surprised the homeowner hasn't experienced more problems than this.

          I think I'm good to go now. Thx

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 Summit 2025 — Design, Build, Business

Join some of the most experienced and recognized building professionals for two days of presentations, panel discussions, networking, and more.

Featured Video

A Modern California Home Wrapped in Rockwool Insulation for Energy Efficiency and Fire Resistance

The designer and builder of the 2018 Fine Homebuilding House detail why they chose mineral-wool batts and high-density boards for all of their insulation needs.

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