1.2 m is far too shallow if you live in Wawa or Thunder Bay. So, where do you live? What type of soils do you have. Frost depth data should be available from MTC - or you local building department. You also need to determine whether you have a frost problem. If you are founded on sand with water table deep (say 3 m deep), the soil should be considered non-frost susceptible and you can get a variance from the depth of foundations. Talk to a geotech in your area.
GTA? What's that? Grand theft auto? So put your foundation on the surface and be prepared to see your deck move with the frost. As long as you don't tie it into anything more deeply rooted in the ground, who cares?
Thank you.
I live in Mississauga. I feel the frostline may be less than 1.2m.
It's a small deck (3mX3m) in backyard, I wish the foundation is simple as possible.
If the deck is not tied to the house, I do not see a problem with it floating, if it is, obviously things change.
You might want to check the local requirements. Is a building permit required? If so, your feelings about frostline depth might be irrelevant compared with what is required to get the building permit.
To kelowna,
I like to separate the deck from house so it'll not need permit. I try to find the frostline because I'm afraid the foundation above frostline and may have big displacement.