Dear All, I have been following this analemmatic thread with particular interest since I have recently been giving advice to a Swedish stone-cutter who wants to set a dial out in her garden. She lives on the cold side of 60 degrees north.
I especially noted: > I have been talking to people who know about road > construction... So have I and I have been learning about `slab-on-grade construction' and `nominal maximum expected frost depths' and so on. In England, the standard frost depth code is 450mm but in Canada it is typically 1200mm and in places which have really cold winters the figure is 1800mm. In my limited experience, the solution has been to use a truly wonderful material called SAND! This works fine in England. You just dig a shallow pit, put in 150mm or so of sand, lay your slate (or whatever) on top and provided you have been careful this will stay level for many years. When I looked at the Brooklyn bathroom-tile dial that John Carmichael kindly drew to our attention my first thought was, `How will that look after a New York winter?' Worse, `How will it look after 20 or 50 winters?' I am very much minded of the maxim `Beauty is only skin deep'. Can some U.S. reader who knows all about cold winters kindly let this temperate Brit know what is likely to be found underneath this dial? Is there really 1200mm of hard-core and elaborate drainage? My Swedish friend advises that they can expect two to three months of -25C temperatures with occasional dips to -35C. Whenever I have stuck tiles on a bathroom wall I find the wretched things peel off after a year or so inside a nice warm house. With frost heave, ice penetration, and differential thawing effects that the Swedes call `shooting', there wouldn't be much to look at come spring if I had laid the tiles on an outside dial. I am feeling a serious lack of experience! Can anyone help? Frank King Cambridge, U.K. -
