No ned for piles and any excessive depth. A sidewalk is a "floating structure", just like a street or highway. Small amounts of movement are usually tolerated. Make sure you have some well draining soild road base, etc. under the sidewalk especially if you have moist and/or sub-base.
Make sure you have a joint between the sidewalk and a structure.
Last edited by concretemasonry; 11-13-2011 at 06:52 AM.
I'm pretty, sure "concretemasonry" is referring to an "expansion joint"
type of material.
You probably don't want to "pin" the sidewalk to the house (with rebar) -
as stated above - the sidewalk is a "floating structure".