White PVC pipes run under the slab where the domestic hot and cold running water tubes are housed and run. These plumbing tubes are part of the Hansen House’s wet wall, a structural wall designed to house plumbing pipes for fixtures like sinks, dishwashers, washing machines and toilets. The tubes are connected into the manifold and then distributed throughout the house to the designated fixture. Consolidating plumbing in a single wall increases efficiency as well as cutting down on building costs. The black PEX tubes are for the radiant floor heat which also run to the manifold where the water will be heated by an electric water heater. The PEX tubing was attached to the rebar which was laid out in a checkerboard pattern on top of the foundation’s 4″ of insulation. Then concrete was poured to form the slab. The kitchen island location and outline were marked by tape on the floor for reference points. After the plumbing tubes were all in place, the cellulose insulation could be sprayed. Netting was installed on ceilings and walls to hold the blown in cellulose in place. The netting was used so that the drywall would not have to be installed before the insulation was blown in, which could cause moisture problems. The windows and doors were covered with plastic to be protected during the spray insulation process. Polyurethane, the yellowish material, was sprayed to seal any plywood seams to ensure a tight building envelope. Because the insulation is blown in an excess of material tends to accumulate; therefore, while one person blows in the cellulose another person vacuums it up where it is sent back to the truck and recycled back through the process. The metal braces seen in the picture below are part of the t-bracing which prevents lateral movement. Rigid foam was added to the cavity so that settling of the insulation was minimized and controlled.
The month of July has been very busy at the Hansen House. Once the insulated foundation was complete the plumbing pipes, as well as mechanical conduit piping, were laid out, run and installed. Plumbing pipes have to be run at a slight downhill slope so that the waste in the pipes can drain properly. Weld-On P-68 primer was used to help join the pipe and fittings. This low VOC product is compliant with LEED Green Building Rating System and can be credited towards indoor environment quality. The same GreenGuard rigid insulation that was used with the foundation walls was installed before the slab was poured. These products contain up to 30% post-industrial recycled content and help reduce energy consumption and improve durability. On top of the 4 inches of insulation the rebar was laid out in a checkerboard pattern used to reinforce the concrete and prevent cracking. The PEX tubing for the radiant floors is also attached to the rebar structure. PEX tubing is a tough, flexible plastic that is easy to layout in loops and bent around corners. The PEX tubing is where the warm water is circulated to heat the radiant floors. Select floors throughout the Hansen House will have radiant heat. The PEX tubing for the radiant heat will run to the manifold in the mechanical room. Here it will be heated with an electric water heater and pumped back through the piping. The electric water heater will be run on energy generated from future solar panels. The concrete is then poured over the PEX tubing and rebar. Using products made from recycled materials is a standard operating procedure for HJLCMS. The concrete for the Hansen House was made with 20% fly ash and is sourced locally. This recycled material content is closely tracked should the need for LEED certification be considered. Fly ash makes the concrete more durable, water-resistant and stronger. Fly ash shrinks the environmental footprint of concrete because it reduces the amount of water and Portland cement in the mix. Once the concrete had set, the power trowel was run over the surface to smooth out any imperfections and get a tight, glossy finish. The more passes with the power trowel will give you a more glossy finish. The broom finish on the concrete floors for the wrap around porches gives a unique and distinguishing feel to these outside areas. A material called River Jack was added to the concrete as the aggregate giving the East porch a textured surface. Check back for the next post as the crew begins to frame out the garage.