New construction, zone 2, south of Houston. The house has a full slab foundation with the top of the slab 18″ above natural ground. The house has a crawl space above the slab by virtue of a 36″ continuous perimeter stem wall of CMU blocks and interior pony walls to support the wood/OSB subfloor structure. The CMU blocks are fully grouted. It will be a closed/unvented crawl space, with 2″ of closed cell spray foam applied to the inside of the perimeter stem wall and the rim joists. The exterior of the house will be brick veneer sitting on a 5-1/2″ brick ledge, so there will be a couple of inches of air space between the inside of the brick veneer and the outside of the stem wall. The framed exterior walls will be sheathed with 7/16″ Zip system, which will drop an inch or so below the framing members onto the outside of the stem wall a bit.

Should the exterior of the stem wall (the CMU blocks) be damp proofed with some kind of paint/spray material to reduce the chance of moisture infiltration into the crawl space, or is the closed cell spray foam on the inside adequate?

Thanks,
Ira