Slab Prep and Pour

February 2023. Bryan and I built the form work for the slab and we got all the reinforcing steel for the footings in place.

After some major weather inflicted delays, in early March the plumbers installed the ground work (all of the drain pipes and vent pipes for the eventual plumbing fixtures) which will be buried in the ground under the concrete slab.

With that work finished, we were able to backfill the trenches and bring in the ABC material for under the slab. ABC means aggregate base course and it is a mixture of course and fine gravel and dirt. It’s called different things in different parts of the country, but it’s used under slabs because it’s easy to get level and smooth, it compacts nicely and it provides drainage.

At 5000′ elevation it gets cold here during the winter, even though we are 30 minutes from the Mexican border. A heated slab is the most comfortable and quiet way to heat, at least the lower level. We decided on a hydronic system which uses heated water running through loops of pipe buried in the concrete. A propane boiler will heat the water and pump it through the embedded pipes via a manifold system which feeds five circuits and two separate zones. There will be two thermostats regulating the two zones.

We were lucky to find a good crew to place and finish the concrete slab. Originally I was going to place a 6 mil poly vapor barrier under the slab, which is standard practice in some parts of the country. Luis convinced me that doing that here would create more problems than it solved. Namely, the top of the slab would cure more quickly than the bottom which would result in cracks. All concrete will crack, but we might as well mitigate it as much as possible. He also helped layout the control joints which are tooled into the wet concrete rather than cut in later. The slab will remain exposed in the finished house, so this was an important design element. ( editor’s note: 10 months later the slab still only has one minor crack outside the control joints)

Getting the slab poured was our goal for this winter, and we barely made it! Now we get to go back to our summer jobs to make some more money so we can carry on in the fall.