What is 50 year frost line?

Answer 1

The fifty (50) year frost line is the deepest depth frost has a possibility of reaching based on a 50 year period of time. This number is important when installing home footings or septic tanks and other piping that are susceptible to damage from frost penetration in to the ground. Frost will penetrate the ground deeper in years with little or no snow as snow generally acts as an insulator for the gorund. In many parts of Southern Canada, the building code standard is 4'-0" or 48" depth for foundations and footings. This means that your structure will generally be safe from frost heave (movement due to moisture freezing and expanding, causing the structure, i.e.: concrete or block basements, to be damaged, cracked or even pushed out of the ground completely) if the footings are a minimum of 48" below the surface of the soil. To find the 50 year frost line for your area, contact your local building department or planning department.