Winter will arrive in North Dakota before we know it, and some people with flooded homes should carry out procedures to avoid further damage if they will not be rebuilding before winter.

Very wet soils will expand when water in the soil freezes, and that’s the case in many areas of North Dakota now, said Ken Hellevang, North Dakota State University Extension Service agricultural engineer and flood expert.

“Frost heaving may lift the foundation and basement wall, causing damage to the foundation, wall and other parts of the structure. Frost heaving also may lift a basement floor, causing bulging and breaks in the concrete,” Hellevang said.

Insulating the basement ceiling and placing insulation on the soil surface on the outside of the basement wall will reduce the potential for frost heaving but may not be adequate to prevent frost heaving in an unheated home.

To place insulation outside the basement wall, Hellevang recommends digging a trench around the house so the insulation is below the ground surface. Place rigid insulation against the exterior of the basement wall and horizontally along the bottom of the trench, then replace the soil to hold the insulation in place and protect it. Do not insulate the inside of the basement wall since that reduces heat loss to the soil and may actually increase frost penetration.

“Of course, adding heat to keep the temperature in the basement above freezing in addition to adding this insulation is the best way to limit the potential for frost heaving that will affect the house,” Hellevang said.

To learn more about preparing a building that was flooded for the winter and illustrations, see http://www.ag.ndsu.edu/pubs/ageng/structu/ae1594.pdf.

NDSU Agriculture Communication – Sept. 9, 2011