When building over a crawlspace, what is the most common framing method?

The most common framing method used when building over a crawlspace is platform framing. This method is particularly favored for its efficiency and practicality in residential construction. It involves constructing the floor of the building one story at a time, using the walls of each floor to form a platform for the next. This provides an easy and effective way to accommodate a crawlspace, allowing for essential services such as plumbing and electrical systems to be routed beneath the floor, and also facilitates ventilation.

Platform framing is advantageous as it minimizes the complexity involved in the assembly of walls and roofs. It's also conducive to rapid construction compared to methods that require more extensive initial groundwork, such as a slab-on-grade foundation, which lacks a crawlspace, or post-and-beam systems that can often be more expensive and labor-intensive.

Overall, because of its suitability for the crawlspace environment and the ease of use in varying construction conditions, platform framing stands out as the prevailing choice in these scenarios.