What about your particular house matters here
Fifteen building features that change the conversation: what your foundation is, what runs under it, what was done to it before you arrived. None of them decides anything on its own, and none of them is good or bad news.
What they do is tell you which questions will be asked and which answers are worth having ready. A homeowner who knows their block walls are hollow, or that the sump has no lid, walks into a site visit able to describe their house — which is the single thing that most improves the quality of the advice they get back.
Full basement
“We have a normal basement under the whole house.”
The standard benchmark, and usually the highest reading in the house.
Slab on grade
“The house sits directly on a concrete slab — there is no basement or crawl space.”
No basement, but the slab is still in contact with the soil.
Crawl space
“There is a crawl space under part or all of the house.”
Exposed earth changes both the entry path and the approach.
Combination foundation
“Part of the house is over a basement and part is a slab or crawl space.”
Additions and extensions frequently mean more than one approach.
Sump pit and pump
“There is a sump pit in the basement, with or without a pump.”
An open pit is a direct opening to the material under the slab.
Drain tile
“I have been told there is drain tile around the foundation.”
A pipe loop that may already reach where a system needs to draw.
Hollow block foundation walls
“The basement walls are concrete block rather than poured concrete.”
The wall cavity can act as a pathway in its own right.
Stone or rubble foundation
“It is an old house with a stone foundation and a dirt or partial floor.”
Older construction, more paths, more that has to be seen.
Finished basement
“We finished the basement and now the kids use it every day.”
More time spent on the lowest level, less access to it.
Sealed versus unsealed crawl space
“The crawl space was encapsulated a few years ago — does that cover it?”
An existing membrane is not automatically a radon membrane.
Attached garage
“Does the attached garage affect the radon reading?”
Relevant to indoor air, mostly separate from soil gas.
Multiple heating and cooling zones
“We have separate systems for upstairs and downstairs.”
Air handling shapes the pressures that drive entry.
A private well
“We are on a well — does that change the radon situation?”
Different source, different test, different treatment.
An existing radon system
“The house came with a radon system — is that sorted then?”
A pipe and a fan are not evidence that levels are low.
Post-tension slab or in-floor heating
“We were told the slab is post-tensioned and cannot be drilled anywhere.”
Real constraints on where anything can be cut.
The other sections
Whatever you have noticed may not sit where you expect. If nothing here matches, one of these probably holds it.
- All three sections — the full index, with what each one covers.
- What we can and cannot determine online — the limits of everything on this platform, in one place.
When reading has taken you as far as it can
Describe your situation and we will tell you honestly whether we can route it to a provider in your area today, or whether we cannot.