Radon Mitigation in Homes With a Crawlspace and Basement Combo
A house built with part of its footprint over a basement and part over a crawlspace, common in additions and split-level construction, needs a radon evaluation that accounts for both areas, since soil gas can enter through either foundation type independently. A system designed only around the basement can miss significant radon entry happening through the crawlspace side of the house.
This mixed-foundation situation is one of the more common reasons a generic, one-size estimate over the phone is less useful than an in-person evaluation, since the two foundation types genuinely behave differently and a system sized only for the basement can leave the crawlspace-side entry unaddressed.
If your home has this kind of split foundation, mentioning it upfront when scheduling an evaluation helps the contractor plan for both areas from the start.
Common questions
Does this mean two separate radon systems are needed?
Sometimes, depending on how the two areas are connected and how air moves between them, but a well-designed single system can sometimes address both if the contractor evaluates the whole foundation, not just the more visible basement portion.
Is crawlspace encapsulation part of the fix in this situation?
It often is, since an unencapsulated crawlspace with exposed soil is a direct radon entry point on top of being a moisture concern. See our page on crawlspace radon for more on that specific mechanism.
Have a number you want read?
Tell us the result and your town in York County, or call and read it out. We will tell you what it points to and what a system would involve in a house like yours.
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