Get matched with top structural engineers in Hendricks, MN

A 4-inch-thick concrete slab can support around 4,000 pounds per square foot if a contractor reinforces the slab with rebar, while that same slab without reinforcements will support closer to 1,000 pounds. For the purposes of a patio, 4 inches in thickness without reinforcement should suffice unless you’re installing heavy kitchen equipment or a hot tub on it. In those cases, reinforcing your slab and sticking with 4 inches of thickness should provide plenty of strength.

You should avoid drilling or cutting into load-bearing beams because removing material will weaken it and increase the risk of structural damage or even collapse. If you do need to drill into a load-bearing beam, speak with a structural engineer first to discuss where it’s safest to drill and the width and depth of the bit that’s safe to use.

The depth of any foundation style depends on your climate and how deep the frost line is, as building code requires that the footers of a foundation—which are built into a monolithic slab—sit at least a foot below the frost line. At the southern tip of Florida, for example, a monolithic slab foundation would only need to sit 12 inches under the soil at the widest parts. On some parts of the Canadian border, the frost line is 100 inches, which would mean a minimum of 112 inches, which is prohibitively deep for a monolithic slab.

Although the two terms are closely related and often used interchangeably, pier and beam foundations and crawl spaces are different things. A pier and beam foundation is made up of concrete piers and wooden beams and creates a space under the home known as a crawl space. There are several types of foundations that create crawl spaces, often collectively known as “crawl space foundations,” but the crawl space itself is separate from the foundation.