Concrete Piers & Rock

[Bluemoon]

I hope to start building based on the Little House plans sometime in June and will be using a "cold climate" version post and beam foundation.  Local building code requires a minimum depth of 4ft for the concrete piers so that they are below the frost line.  My property is located near Kenora in Northwestern Ontario so I am in the heart of the Canadian shield with many beautiful granite rock outcroppings.  These same outcroppings can also be a real pain when it comes to building things.

Because of this, it is very possible that when I start to drill holes for the sonotubes I may or may not encounter solid rock and it could be a few inches below grade or many feet.  Building a foundation on solid rock would normally be great but the problem is not knowing what is below the surface.  So my question to you is... if I do happen to hit solid rock should I drill into it and use rebar to pin to the concrete pier or should I try to relocte the pier away from the rock?  My gut says use the rock as part of the foundation if at all possible but I would like to get your views.

Thanks   

[Redoverfarm]

That is what I would do if it is an alternatve that the local authority will allow.  In doing so I would anchor the rebar at an angle into the stone having the rebar cross each other above the rock to the center of your pour and tie into the verticle rebar in your sonotubes.  Once you concrete is poured it will prevent it from lifting off the rock.  Standard verticle pins can lift out.