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

When Block Foundations Go Bad

Steel bracing and improved drainage give new life to cracked and wet walls.

By Donald V. Cohen Issue 117
  • X
  • facebook
  • linkedin
  • pinterest
  • email
  • add to favorites Log in or Sign up to save your favorite articles

Synopsis: Concrete block foundations, popular in many parts of the country, are susceptible to a variety of structural problems caused by water infiltration or improper backfilling around foundation walls. This article explains where the trouble starts and suggests a number of ways to reinforce foundations that are showing signs of distress. Some fixes do not require extensive excavation.

When people ask me what kind of house foundation I prefer — poured concrete or concrete block — I tell them to take a look at the Yellow Pages under “Waterproofing Contractors.” Here in southeast Wisconsin, where I work as a building inspector and engineer, such a search will turn up more than 50 companies specializing in repairing cracks and stopping water seepage in concrete-block foundations.

This is not to say that concrete-block foundations are always a bad idea. They can perform well with proper drainage and appropriate reinforcement, but these conditions are not always present. Gradually, time and the elements can undermine the health of a block foundation, even a well-built one, a fact I am reminded of when doing inspections for prospective home buyers. I constantly see wet basements, or foundation walls that have cracked, buckled, tipped and sometimes even collapsed.

Soil pressure works against the foundation

Most problems associated with concrete-block foundations can be traced to two related factors: improper drainage and the seasonal expansion and contraction of soil, which puts pressure on foundation walls.

Water seepage is the most common problem I see, but water-soaked soil around the foundation also imperils the structural integrity of the walls. When the ground freezes and thaws, pressure builds against the walls. Common failures are horizontal cracks along mortar joints where the wall has been forced in due to soil pressure. I usually find cracks like this between the third, fourth or fifth courses from the top in a typical ten- or 11-course wall, which corresponds to the frost line. Often accompanying these cracks are other signs of failure: vertical shear cracks in the corners, step cracks following the mortar joints and walls pushed off the mortar joint between the first and second courses of block. Unrestrained walls sometimes slide under the joists in response to soil pressure, tipping the wall out of plumb.

Water and soil cause other problems, too. Consolidation or settling of subsoil due to heavy rains, or a substantial loss of moisture in the soil, can undermine the foundation from below. This settlement may allow footings to drop, causing vertical and step cracks as well as tipped and cracked concrete floors. In some cases, this kind of settlement causes the walls to tip outward.

Look for problems outside the foundation

The first approach to fixing a wet basement is to correct the grades around the foundation so that water flows away from the walls. Make sure downspout drains, sump-pump discharge pipes and storm sewers convey roof and surface water away from the house. Low spots around the foundation are likely to collect water, so any depressions should be filled.

For more photos, drawings, and details, click the View PDF button below:

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
View PDF

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. artampone | Feb 28, 2021 04:01pm | #1

    I'm repairing a block wall on an old farmhouse that has bowed in due to soil pressure and poor drainage. That issue is in the process of being fixed with a curtain drain and external waterproofing. The block wall is bowed in about 3" from plumb at the center on a 76" high wall. I plan to brace the wall with i-beams to ensure no further movement. The question is on methods to safely and effectively push the wall back into place. There are no parts where the wall has sheered, only a bow in the center.

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

Pros of Apprenticeship Programs

Apprenticeship programs can be a valuable tool for residential builders to recruit, train, and retain skilled employees, offering a structured pathway for career advancement and equity in the trades.

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

  • Beat the Heat: Cool Innovations
  • Seven Ways to Remove Paint
  • One-Person Precision
  • Ranch Redux

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

"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

Video

View All Videos
  • FHB Podcast Segment: Designing and Building an Efficient Slab-On-Grade Home
  • FHB Podcast Segment: Is Foam Against Form Boards a Good Idea for a Garage Slab?
  • FHB Podcast Segment: Lime Wash Recipe for an Old Concrete Basement
  • FHB Podcast Segment: Masonry Chimney Care 101
View All

Site Work and Foundations

View All Site Work and Foundations Articles
  • FHB Podcast Segment: A Permanent Wood Foundation in the Adirondacks
  • Concrete Funnel
  • A Strong Case for Wood Foundations
  • Podcast 596: Broken Trusses, Frost-Protected Foundations, and Air Control Methods
View All Site Work and Foundations 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

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