On 9/1/97 Tom McHugh wrote: >Before setting an outdoor dial pedestal, I would like to get >an assortment of opinion as to the effects of hard freezes >on dial alignment. I do not know any diallists locally, here >in Fort Fairfield, ME, to contact directly, so I thought maybe >someone on the List has some ideas about frost heave on >dials. > >For what its worth, with regard to other structures, local >opinion is at some variance. Some people say that a secure >foundation must go down 8 feet to below the frost line, and >others say that if the ground on which something is set is >of the same moisture content as adjacent ground, that one >spot will not suffer more from frost heaving than any other. > >Chances are that I'll just build one on the surface and see >what happens this winter. By the way, temperatures here, >in January, get down to 40 below zero. > >Opinions of others would be greatly appreciated.
Hi Tom, Here in southeast Vermont, where the winter temps don't go much lower than -20 F, we figure that for stability one puts in a foundation which goes below the frost line, which varies from about 4 to 6 feet below grade level, depending upon whether or not there is undisturbed snow cover. I built a log cabin (chop by chop, not prefab) almost 40 years ago with a foundation of rocks set on the surface, and it has served just fine - rising a couple of inches in the winter and falling back in the spring. But I notice that cemetery headstones react to freezing and thawing over time by tilting this way and that. Myself, for a personal dial pedestal I'd build on the surface, and, when necessary, do a quick springtime leveling. If that turned out to be too tedious, I'd set a concrete pier below the frost line. Let us know how it turns out. Mac Oglesby
