Using old roof footings for a ground-level deck

Question

I had a 40 year-old, asphalt shingled, hip roof (14x18) over a concrete patio that had 4 posts w/footings that supported it in a line opposite the house. The footings, that are still there and were not disturbed in the roof demolition, are about 6' apart. Could I use those footings to support a beam for a ground-level deck?

The ledgerboard will not be attached to the house but just will lay on the concrete patio (which is very stable). Then there's a significant slope to the footings (8" over 12'). My thought is to lay a beam on short blocks across the footings to raise the outer edge of the deck in order to get a less drastic slope.

Then from the beam, I'd extend the deck another 6' and use pier blocks to support the outer edge of that portion.

Does this sound like a good idea? Any and all comments are welcome.

Thanks!

Answer 1

Using the old footings sounds fine, so long as they've done their settling or were poured off kilter to begin with, it's those new ones I'm not too keen on, that will just sit on the ground. If you are going to use pier blocks, you might as well use the old questionable footings; can't be any worse then just using a rock.

You mentioned frost which means 3~5' down for the footings, at least where I live. For reference and how to do it right (in its entirety): Chicago Deck Code (footings: p. 48 and 49)

I will admit that it not being attached to the structure and not being a fire escape, you could say meh to some of the more colossal building techniques contained therein, but don't be surprised when it sinks those pier blocks into the ground and ends up looking like your sloped patio.

Answer 2

In a lot of areas, if it is less than 2' high and not attached to the house the deck is considered landscaping and building code does not apply.

Check your local code/regulations/bylaws.

I am not fond of mixing deck blocks/piers with proper footings. I think weird things could happen when the ground moves from frost, etc.

That being said, if the deck is below 2' (everywhere), then really, just do whatever you want (within reason).