I'm looking to install a 30' decking platform (for a yurt), 3' above grade, on a plot of land I own. The site has a mild grade (5-10%), made up of metasedimentary rock, with ~1" of organic matter at the surface (not enough to dig into). What footings or reinforcement strategy would you recommend for a site like this?
sedimentary rock can be quite soft / should be easy to drill. fine for compressive strength.
- drill 8" deep holes using rotary hammer 3/4" quad carbide bits
- blow out the holes / clean holes with hilti wire brush
- epoxy (HY150) 5/8" rebar into holes and have that extend up into your footing
- 8" diameter sonotube the footings to get yourself to the height you want for your platform
- put post anchor saddles into place on the sonotube to receive your beams or posts