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

Precast Concrete Foundations

TX65 | Posted in Construction Techniques on November 29, 2011 10:04am

I live in an area known for expansive clay soil and with a recent and currently ongoing drought, conventional slab foundations are suffering the effects.

I have read about precast concrete foundations like those from superior walls designed for basement type foundations, but we don’t build basements in this area. 

I wanted to put the idea out there for discussion about precast concrete slabs.    One concept I found was from a company called Cell Blocks, Inc which are used for cell towers and mechanical buildings.  http://www.cellblocksinc.com/

In this commercial application, the blocks are 7’x7’x2′ and are interlocked together and post-tensioned to form a single mass slab.  

My thought is that precase slab modules can be brought on site and set on a leveled compacted gravel base, post tensioned and framing can be begin immediately.  

The compacted gravel base would isolate the floating slab mass from the expansive soil and the precast system would remove doing formwork, pouring concrete and waiting for curing.

While a 2 foot thick slab may be overkill, the concept could be applied to say a 12 inch thick slab set on a 12 inch compacted gravel base. 

Further research as shown the precast has also been used to create highway and air port runway sections so clearly, strength and durability are not an issue given the abuse those applications put on the concrete.  

I know this is out of the box thinking so please think forward a bit as you give your thoughts.  

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

Replies

  1. TLE | Nov 30, 2011 06:34am | #1

    I suppse

    I suppose it could work - the only caveat would be chases for utilites, most important plumbing drains.

    Terry

    1. TX65 | Nov 30, 2011 10:47am | #3

      Terry

      Where I am in Texas, we have to build above the 100 yard flood plain so the thought was rather than building on piers that raise the first finished floor to 60-72 inches, just take the first finished floor up to 120-132 inches and use the wasted space below as a garage - actually would be a rather large garage but who would complain about that? 

      In that way, the plumbing and other utliities would run below the first finished sub floor and the only through slab penetration would be the main sewer connection which could even go through a sidewall and connect through a sewer connection immediately next to the slab requiring no slab penetrations.    It would be kinda of like a basement built on grade.

      While 7x7x2 blocks weigh close to 15,000 lbs each,, a smaller 4x4x1 block would be much more managable weighing in at say 2400 pounds per block.  

  2. DanH | Nov 30, 2011 06:57am | #2

    I'd suggest you try to find some industry association you could consult.  There must be a "Precast Concrete Association" or some such.

    1. TX65 | Nov 30, 2011 10:51am | #4

      Dan,

      The precast concreate association are on my list to contact, but my thought by asking the question here is to get opinion from people without a vested interest in precast concrete who would very likely say "no problem, yes could be done" vs people in the trades who can view it from a different perspective and may think of it as a time and labor savings with no formwork, concrete pours, stripping forms and waiting for curing.

      1. doormatt | Nov 30, 2011 04:30pm | #5

        As a structural engineer, I do a lot of commercial work throughout Texas and am very familiar with the expansive soils issue.  I also do a lot of work with precast/prestressed hollow-core concrete panels.  The panels are 4 feet wide and come in varying lengths from 10 - 45 feet.  Thickness varies from 6" to 12" depending on load requirements.  As the name implies, the panels are formed with hollow cores running along their length to limit their weight.  We typcally see this type of material used in hotel and multi-family construction... where it allows for clear floor spans from exterior walls to center corridor walls.  That's not to say it couldn't be done for single family residential projects, but I believe it would be cost-inhibitive.  You are correct, you would save on labor and time associated with formwork, but there would be added costs for transporting the panels to the site and having a crane on site for installation.  The main advantage to using these panels is speed of construction, which isn't necessarily a priority in residential construction like it is in commercial.

        Regarding the expansive soils, I would support the ground level panels on grade beams that rest on a deep foundation system (drilled piers).  I would provide a void below the panels and finish grade to allow for soil movement.  This again, would be extremely expensive for residential construction.  I belive you're better off going with an engineered slab and/or floating walls.

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