The foundation is stone or rubble
“It is an old house with a stone foundation and a dirt or partial floor.”
Stone and rubble foundations are irregular by nature. The joints between stones, and often the floor itself, provide many small paths rather than a few identifiable ones.
Approaches that work well on a modern slab may need adapting, and there is usually more that has to be seen rather than described.
Why this matters
What it changes about the decision in front of you.
- The wall is not a continuous barrier, so sealing individual points rarely addresses the whole.
- Many older buildings have partial slabs, dirt floors, or floors laid over rubble, which changes what a system can draw from.
What it could influence
Where the effect is likely to show, and in which direction where that is knowable.
- A membrane approach may be relevant where the floor is not continuous concrete.
- Headroom, access, and the condition of the masonry all affect what is practical.
What this does not settle
What still stands. Noticing a problem is not the same as losing the evidence.
- An old foundation does not mean mitigation is impractical — these buildings are worked on routinely.
- It does not mean levels are high; measurement establishes that, not the construction date.
- It does not establish which approach fits, which is more site-dependent here than in most buildings.
What a professional is likely to ask
Worth having answers ready. None of these is a test you can fail.
- What the floor actually is across the whole footprint, which is often not uniform.
- The condition of the masonry and whether it has been repointed or parged.
- Whether the building has been extended or underpinned.
What you can check yourself
Things you can establish today, without anyone visiting.
- Whether the floor is concrete, earth, or a mix, and where it changes.
- Whether the walls have been parged, and whether that surface is intact.
- Headroom and access throughout.
What genuinely needs somebody on site
Where this platform stops. These are not questions a website can answer about your house.
- Nearly everything about how gas moves through this construction, which is why site assessment matters more here.
- Whether the floor can be sealed or drawn from, which depends on what it is made of.
Categories a next step could fall into
Unordered, and none of them is a recommendation. Which applies depends on things this page does not know about your situation.
Related reading
- Cracks and sealing — Sealing is a supporting measure inside a system, not a substitute for one. Both halves of that sentence matter.
- Crawlspace mitigation — A crawl space is mitigated by sealing a membrane over the soil and drawing air from beneath it — more labour than a slab, and a common source of quote differences.
Sources
- U.S. EPA — Consumer’s Guide to Radon Reduction
When you are ready to talk to somebody
Tell us about your home and what you are trying to work out. We will tell you honestly whether we can route it to a provider in your area today.