i know, i know….i really shouldn’t be sharing all this wonderfully exciting news so soon in the project! JK, but….these details are critical to long-term building performance and durability. its important stuff, it costs A LOT of money, and we’ll never see it again once its all buried! the series of following photos describes the layers:
4″ diameter PVC radon vent piping being installed in layer of 3/4″ crushed stone which lies on top of about 3′ of compacted gravel as (we had to over excavate inside the foundation due to some questionable existing soils – fortunately, we had good, hard, native soils at the footing level). the stone layer has sufficient voids to allow air movement. if the indoor air quality test (after construction) indicates unacceptably high radon levels, then an exhaust fan will be installed on the other end of the vertical pipe (in the attic) to create a negative pressure under the concrete slab and exhaust that nasty radon to the outdoors.
lots of pipe! the larger diameter pipe laying on the stone is the radon vent piping (described above). the rats nest of smaller white pipe with the vertical legs is the waste (sanitary sewer) piping. as you can see here, most of the plumbing in this house is concentrated in the same area. of course, to make sure the water flows downhill, the sewer pipes must be properly pitched to drain toward the front of the house, under the foundation wall and then head toward the street. the sewer pipe in the street is reported to be 12′ deep! so, no real concern about pipe pitch.
this cool photo was taken from atop the excavator (with my iPhone and fisheye lens attachment – very cool recent b-day present from my client!). it shows all the pink insulation (6″ rigid insulation/R30) below the slab. all the pipes and stone (shown above) are now buried beneath the insulation. next up is the poly vapor barrier, wire mesh, radiant heat tubing….THEN, the concrete slab will be poured. the slab will eventually be stained & sealed to become the finished floor.
i hope you took notes. there will be a quiz!