Sub-Slab Depressurization Systems
Sump-System: Sump crock is sealed and suction is drawn from the drain loop.
Sub-Slab or Block Wall System: Hole is drilled in basement slab and suction is drawn from under the slab. Block wall systems are rarely used but can be effective in hard to mitigate homes.
Outside views of a typical external system. The systems exhaust must terminate above the roofline.
Internal System: Sometimes it is possible to route the system through a garage or even closets in the home to hide the piping. The exhausts then exits the roof and looks like a normal stack pipe.
Operational indicator: Shown here is a U-tube used to monitor system operation. The systems are so quiet it is otherwise difficult to monitor.