I live in Ontario, Canada, and the requirement for posts/bases is 4-feet deep in the ground, taking the frost line into consideration.
Now I saw this in Google images. I was just wondering if I can do this? Does the ENTIRE ditch need to be at least 4-feet deep? What will happen if the ditch is say, just 1-foot deep? Will the whole thing heave and crack/break during the winter cycle?
Best Answer
Best advice is to dig the whole thing down to the level below frost line. It is also the standard practice to put down a bed of gravel at the bottom and lay in a reinforced concrete footing that lies completely below the frost line and is wider that the fence support wall. Say 12 inches wide. This gives the poured wall structure something solid to sit on that does not heave and will also help mitigate problems with ground movement and settling.