We worked on a home built in 1974 where radon levels tested at 4.0 pCi/L. The home includes a crawl space with a cement slab that is large enough for access, which allowed for a more complete system design.   A three-pipe radon mitigation system was installed to cover all areas. One pipe was placed in a small closet, another was run horizontally into the slab, and a third was installed in the crawl space. The crawl space line was routed into the shed, where the fan was installed, and then vented through the roof of the shed. This setup allowed the system to operate effectively while keeping the fan location separate from the main living space.     We also discussed the use of Aspen as part of the project considerations.