Decks, Patios, Porches and Docks - Frost Jacking

My deck is attached to the house on one side and the outer post supports were set in concrete but have heaved because they were not properly done. To fix this and avoid future frost jacking I have read other posts about how to do it right. I agree that the best way is to go below the frost line...use sonotubes...embed post anchors, etc, but thats not easy when working under an existing low headroom deck.

None of my sidewalks have frost jacked out of the ground, so as an alternative, what is wrong with setting the deck posts on concrete pads on grade? Would not that avoid frost jacking?

I can imagine that uneven settling might be a problem, but that would be easy to adjust, and sway bracing would keep the deck stable.

I'd bet your side walks have moved with the frost. Because it is a larger span and carries no weight except its own it just isn't noticable. Deck posts usually set on a smaller area of concrete and have the entire load of that portion of the deck. A 4X4 post sitting on 1 square foot of concrete has more pressure per square inch than a sidewalk that is probably 3' X 8' sections. :)

Maybe my sidewalks do move somewhat during the winter, but they don't come up out of the ground like the deck posts did. My point is that frost jacking will move objects up and eventually completely (or mostly) out of the ground if the conditions are right.

So why not start at grade and avoid the jacking effect? I know it isn't as good as doin all the grunt work, but won't this be better than the system that failed?

Please understand that I am only considering this as an alternative to an otherwise difficult fix.