TL;DR
A capillary break is a material layer that interrupts the wicking of ground moisture upward through concrete and into framing, since concrete's fine pores pull water like a sponge against gravity. Standard locations are a polyethylene sheet or rigid foam under slabs, a membrane or gasket between footing and foundation wall, and sill seal between concrete and the wood sill plate, with 4 inches of clean coarse gravel under slabs serving the same role.
What it means
A capillary break is a material layer that interrupts the wicking of ground moisture upward through concrete and into framing, since concrete's fine pores pull water like a sponge against gravity. Standard locations are a polyethylene sheet or rigid foam under slabs, a membrane or gasket between footing and foundation wall, and sill seal between concrete and the wood sill plate, with 4 inches of clean coarse gravel under slabs serving the same role. Building science programs and modern energy codes treat these layers as essential to dry basements and crawl spaces. Retrofitting one is nearly impossible, which is why damp old slabs get vapor-barrier flooring systems instead.
Where it sits in the glossary
Capillary break is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
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