Crawl Space vs. Poured Concrete Foundations

When I began building homes, we use to frame our forms out of 2 X materials and we would stack them and cleat them together with other 2 Xs. After this we would frame a short wall and clad it with plywood. We needed to over brace these forms to prevent blow-out from the concrete. Then we started building our 2 Xs wall and sheeting them with plywood and using snap ties to prevent the blow out. We use to coat these forms with oil (old motor oil). Then poured concrete foundations became the way and forms were not as deep as they once were.

With time, technologies come and go, what was once new becomes obsolete. Many times, the old obsolete method is seen in a new light and it is considered new again. I am considering going back to the crawl space foundation. With a twist.

I am doing so because I have just poured a concrete foundation which was 24” deep and 12” wide. By the time I had finished digging the footing for this 38” by 24” project I had 15 cubic yards in the footing and another 15 for the slab. Concrete is not a sustainable product and we therefore need to use it wisely. With the amount of steel and concrete that was required to build that foundation I am uncertain as to weather or not it was worth it whole cost (monetarily and opportunistic.)

Therefore, I will present my argument to why we should reconsider the crawl space foundation with a twist.

With the use of MDO (Medium Density Overlay, a plywood )forms the wood needed to form the foundations has been greatly reduced and MDO though more costly than other plywood and its reusable in these applications if taken care of properly. We must clean and apply some form of concrete release agent before use and clean and reapply this agent after use.

But the pour of a slab inside the footings would be eliminated and on my last project it would have reduced the concrete consumption by 50%.  The cost for the floor joist and the plywood flooring installation would have been lower than the cost of the concrete, its pumping and finishing.

Also, if down the road in years to come there is a problem with plumbing or something else ran through the concrete it is more costly to repair than if the home had a crawl space. Maybe the next owner does want a tub shower combination. Maybe they want a shower because of age or medical conditions. The swap out is far simpler with the crawl space than with the poured concrete. The crawl space foundation is better on our bodies than the concrete pour foundation. The crawl space takes a little longer to build, but it reduces cost to the other trades because of the ease and accessibility to perform their task.

The crawl space foundation is similar to the basement and daylight basements but they do not require footings at those depths. A footing is typically must be below the frost-line but the frost-line changes with location. In some areas it is at it maximum in the USA at 100 inches but in others it is at 0 inches so where the frost line is deep it makes sense to have more basements than where it is at 0.

We used to say the advantages of the poured concrete foundation were:

• High customization and versatility
• Resistant to frost heaves and freezing conditions
• Seamless construction with minimal weak points
• More durable than concrete block installations

Cons

• requires rebar and other form of reinforcement
• Excavation and solid footing required
• Weather can delay concrete pouring time
• Temporary forms must be built before concrete pouring.

The Pros and Cons for the crawl space were as follows

Pros

• Less costly than the basement foundations
• Deep footing anchor home against frost heave and freezing conditions
• More space and accessibility for mechanical systems

Cons

Cost more than slab on grade or poured concrete foundations

Requires excavation to build

Moisture and pest issues are possible.

These issues need to be reevaluated in light of what new technologies have made available. These must be weighed against the true coat of these foundations and then an educated decisions can be made.

• Note: Images on this blog site are from a free source or taken by the author. No image or group of photos is intended to represent the people the author serves. The author does not care about Race (that is a politically correct term that he does not like because we are all of the same Race, the Human Race. He prefers the term ethnicity, color, religion, sex, gender, marital status, disability, genetic information, national origin, source of income, Veteran or military status, ancestry, citizenship, primary language or immigration status.) He is a service provider for all people. We will all rise together when we band together and help one another. Joseph Erwin is a Real Estate Broker, DRE # O2131799, and a CA general contractor # B 696662. He’s a member of the CRMLS and The East Valley Association of Realtors located in the Inland Empire region of Southern California.