At present I have a small 8x10 cedar deck which I would like to enlarge to 12x11. The present structure is approx. 15 yr. old appears very sound. It has a 10 ft 2x8 length lagged onto a concrete block wall and 3 concrete sono tube piers equally spaced parallel to and approx. 6.5 ft. away from the block wall. (the 8 ft. deck has about 1.5 ft. overhang beyond the twin 2x8 beam on the 4x4 posts on the piers). The deck is approx. 4 ft. off the ground. Would it be reasonable to set 3 deck blocks (approx. 4 ft. apart), parallel to and approx. 5 ft. from the sono piers then just come off the existing beam with joist hangars? To increase the 10-foot length I have a choice of lagging on a 2 ft extension on the block wall, and/or scabbing onto the existing 10-footer or placing another deck block.
Answer:
I think the system you describe will be about as good as it gets. You haven't compromised structural integrity and that's about the bottom line of it. Aesthetics is your next consideration and with a deck 4' off the ground, your imagination is the only thing that can limit that.
