MAX-24-Dean
Veteran Member
Used to install two post and 4 post lifts and alignment racks as part of my job.
Read the manufacturers installation instructions for depth of concrete required. 4" of concrete was typical for a two post lift that had a 9,000 lb rating. The post bases had angle iron that typically spread the foot of the post base out over 3 feet. I have seen some of these lifts 30 years later still in operation on the 4" slabs.
4 post lifts sometime required a 6" depth for a 24" x 24" area in the slab where the post was to be installed. Post was installed in the center of the 24" x 24" area.
Read the manufacturers installation instructions for depth of concrete required. 4" of concrete was typical for a two post lift that had a 9,000 lb rating. The post bases had angle iron that typically spread the foot of the post base out over 3 feet. I have seen some of these lifts 30 years later still in operation on the 4" slabs.
4 post lifts sometime required a 6" depth for a 24" x 24" area in the slab where the post was to be installed. Post was installed in the center of the 24" x 24" area.