Sleeves of PVC conduit protect the tubing where it passes through the foundation wall and up into the driveway slab. The conduit on the far right carries low-voltage wiring for the heat sensor embedded in the drive.
After the crushed stone base is spread and compacted, 1-inch extruded polystyrene board is laid over the entire snowmelt area.
Finally, before the pour, the temperature and humidity sensor is positioned in a bed of mortar so that it ends up dead level with the final surface of the concrete (left) — a critical detail.
To avoid damage to the tubing, control joints should never be cut after the concrete sets. Instead, use plastic strips or a similar technique to form control joints when the concrete is placed. Sections of black closed-cell-foam pipe insulation protect the tubing against slight movement at control joints.