After many years of adjustments and modifications Dawson City YT has determined the best way to build on permafrost is to raise the building up about 3 feet on cribbing and allow the cold air of winter to get under the building, keeping the soil under the building frozen. Seems when you place the building on grade it warms the soil over time and the thawed soil turns into soup and the building sags or heaves with the changes in weather. The cribbing can be adjusted as needed to maintain a level structure. Same thing goes for the sidewalks of Dawson City YT. They are elevated boardwalks and nearly all the streets are dirt/gravel (not paved). Removing your dirty shoes when you get to the library takes some getting used to but, paved streets and sidewalks heave and crack.