A Different Kind of Foundation
When we first started planning our house we assumed our foundation would be like many others in the area. The typical footers with stemwalls, we researched using Insulated Concrete Forms and were sold on the idea of having an insulated basement or crawl space. All of that changed because we made the smart decision to hire both a structural engineer and a geo technical consultant.
Our property is on the Animas River in Durango, CO. and it sits up about 8′-0″ from the nativ soil due to the fact that sometime in the 70’s the city of Durango dumped a ton of fill material on the land when they were building roads in the city. The fill unfortunately was not super awesome, filled with huge boulders, and tons of rocks. However, there was an advantage to all of this fill, the flood plane. Because of all of the material dumped on our site we were now 4′ above the 100 year flood plane. This marker actually changed last year as FEMA is remapping most of the country and raising the flood plane levels.
So now what, Trautner Geo Technical Engineers came out and preformed a soil analysis and what that found was crappy soil sitting on top of crappy sandy native soil. Now to the structural engineers. After several iterations, we have ended up with a raft foundation. We are only going to have a crawl space, to aviod flood insurance, but it is going to be an awesome crawl space due to the fact that we have to pour a slab.
Think of our foundation as a thick slab with sides (hence the raft) The 8″ thick slab will spread the load over the entire footprint of the house mitigating any problems with soil, rocks etc. In addition to the super thick slab we also compacted the soil and added engineered soils. See FHB article about Soils.
On top of the slab we will be adding 32″ tall stem walls using Build Block a company out of Colorado Springs, thus creating our beautiful crawl space. While this type of foundation is atypical we are really excited about it. We know that our engineer is recommending only the best and although it is going to cost slightly more than a traditional foundation we are prepared to spend the money because we feel like it will be worth it in the end!
To see more photos of the foundation progress check out our blog Design House Love: Foundations
We will be pouring concrete soon!