Seat boulders set in concrete

[earthworker]

How would you recommend setting round irregular seating boulders in a concrete plaza.  I know I could just set the boulders on a compacted sub base with a an exp jnt. w/sealer between the conc and boulder.  Is there a better way?  How does this hold up over the years?  Should the control joints be laid out in a particular way?  Anyone have long term examples that have held up.  The project is in Denver so freeze thaw is extreme.  Just curious thanks for the help.

[nca]

We’ve done this on quite a few projects lately with the technique you mentioned — expansion joint and sealer caulk. A good example in my opinion is Flatirons mall (outdoor section), particularly the area behind BC Surf&Sport there are a number of irregular sandstone boulders set in concrete.

[Jason T. Radice]

Depending on the size and shape of the boulders, you can pour pads for them (6″ to 8″ deep with reinforement) and simply set the boulders on the concrete pads. Might be an easier way to go. Your installer will love you.  

[Author]

Posts