Pouring the slab and all that comes before

Jenny moisture conditioning the engineered fill before compacting. Some of the electrical conduit has been installed.


A high speed conveyor shoots 3/4 inch gravel into the foundation. We added about 6 inches of this material.


The gravel was rough leveled around the conduit and plumbing.


The 6 mil vapor barrier is being placed in the foundation and the seams taped.


The high speed conveyor shot 3-4 inches of sand into the foundation on top of the vapor barrier.


The 2' blueboard foam is laid out on the sand, seams taped and the radiant tubing is stapled in position.


A closer look at the radiant tubing and plastic staple system


The upper bedroom slab is poured and dry colorant/hardener is worked into the surface. The garage slab is being poured with no colorant added. The main floor slab was poured the following day. All slab work started at 4:00 am to allow it time to set up before the afternoon rains. We were blessed with a couple dry days.



The next phase of the project was installing all the conduit for the electrical and media wiring. The conduit we placed in the footers was now linked together to allow pulling wires under the slab and into the cavity between the inner and outer adobe walls. In addition we assembled the domestic water circuit which includes a hot water recirculation loop that will eliminate the need to open the faucet and wait for hot water. The loop is on a timer that will circulate the hot water during times of the day when it is needed. We also installed the supply and returns for the radiant floor heating system. Dave Himes with Southwest Geothermal laid the zones out and set up four manifolds within the house that will run two zones each. We set up two additional zones in the garage that will be used to keep the area usable as a shop during the coldest months.


All the domestic water lines and the radiant supply and return lines were wrapped in insulating foam tubes. Once this was done, we back filled the area inside the footers with 3/4 inch gravel. We used a truck with a high speed conveyor that could throw the gravel over 100 feet. This saved a lot of work since the only other option we had was to hand carry the gravel in buckets. The gravel was leveled, compacted and then covered with 6 mil plastic vapor barrier. Jenny laid out the plastic and taped the seams. Just as she finished the last seam, it started to pour. We had about 1 1/2 inches of rain and we returned Monday morning to a lake. The day was spent pumping out the water.


The following day the truck returned to finish the back fill with sand. The truck threw in 3-4 inches of sand which we then rough leveled. Over the next three days, we used the laser level and a 4' piece of 2x4 to level the sand before laying down 2 inch blueboard. We taped the seams and were then ready to layout the radiant tubing. The radiant tubing was fixed in place with plastic staples pressed into the foam board. The depth of each material added to the interior of the foundation was worked out so we would wind up with 5 1/2 inches of concrete for the slab. This will provide a substantial thermal mass for storing heat.