Yes, the tires can be used for structure. It's recommended that 20% of the pond should hold structure. Each structure should be at least apx 10 in dia. & as high as not to be unsightly protruding above the water.
There are several threads here on using old tires. Drill, saw or somehow make holes for air to escape before placing them. The holes should be large enough that they won't later clog with mud, algae ect.

Pond Boss Subscriber & Books Owner


If you can read this ... thank a teacher. Since it's in english ... thank our military!
Ric