Stepped foundations may need multiple suction points
A segmented slab will not always hold a pressure field from a single point. Ask the contractor to explain their design.
York County, Pennsylvania
Radon guidance for Glen Rock, in the valley of southern York County.
Call (717) 555-0143Glen Rock sits in a valley in the southern part of the county, with older housing built onto ground that rises sharply on either side. Valley and hillside sites produce a high proportion of partially below-grade and stepped foundations, and those are consistently the most design-sensitive buildings to mitigate.
Where a foundation is stepped — part of the basement at one level, part at another — the slab is effectively segmented, and a single suction point may not establish a pressure field across all of it. This is exactly the situation where the number of suction points in a quote is worth questioning, and where the post-mitigation test genuinely earns its place.

A segmented slab will not always hold a pressure field from a single point. Ask the contractor to explain their design.
Where the design is less certain, post-mitigation testing is what confirms the system covers the whole floor area.
Certification is the floor, not the ceiling. Once you have confirmed a firm on the DEP list, ask specifically about their experience designing for segmented foundations.
A single post-mitigation reading on one level can miss an untreated section at another. Ask where the test will be placed and whether one location is enough.
Independent guidance on radon testing, mitigation costs and DEP-certified contractors for homeowners in Glen Rock and the surrounding parts of York County.
Ask about a test result, what a Glen Rock mitigation quote should include, or how to check a contractor’s DEP certification.