Radon Mitigation in Minneapolis, MN

A City Built Mostly Before the War

Most Minneapolis houses predate 1950. Longfellow, Powderhorn, Standish and Northeast are full of 1910s–20s bungalows and story-and-a-halfs, with up-and-down duplexes on the corner lots. The streets around the lakes and Lowry Hill carry larger stucco foursquares and period revivals. Camden, Nokomis and the far south fill in with post-war houses. Newer slab-on-grade townhomes and infill are going up near the river and the light-rail lines. Nearly all of the older stock sits on a full basement, and that basement is where the reading is taken.

Floor Drains, Coal Rooms and Block Walls

An old Minneapolis basement has more openings to the ground than a modern one. The laundry floor drain is often the only drain, and its trap dries out. There may be no sump basket and no drain tile at all. Walls are stone, clay tile or hollow block, all porous across their height, and the old coal room or cistern leaves a patched opening in the floor or wall. Each of these is a path for soil gas, and each has to be dealt with for a system to work — usually with a trap insert on the drain and a dedicated suction pit cut through the floor.

What Is Under the City

Minneapolis sits on glacial sand, gravel and till laid over limestone and sandstone bedrock — the same Platteville limestone and St. Peter sandstone exposed at St. Anthony Falls. The Chain of Lakes follows an old buried valley filled with glacial sediment. The practical point is that sub-slab material varies from one neighborhood to the next, from loose sand that lets a fan reach the whole basement from one hole, to tighter till that needs more than one. We check before designing.

Duplexes and Shared Basements

Up-and-down duplexes are a Minneapolis signature, and radon in them is a shared problem. The basement under both units is one space on one slab, and the lower unit is often the lowest lived-in level. A single system protects both. That makes it a conversation for both owners, or for the landlord and tenants, before anyone books — something worth settling early if the building is being sold.

Working Across Minneapolis

We cover the whole city, from Northeast and Camden to the Richfield line. Most jobs begin with a 48-hour test in the basement. Where the number is high, the fix is usually a sub-slab system with the floor drain and wall joint sealed as part of the job, and a pipe route chosen to stay warm through the winter.

Minneapolis Radon FAQs