Understanding the Reviewer’s Comment

The under-floor access refers to an access opening to the crawlspace.

Crawlspaces are located below the main floor framing and above the foundation.

The International Residential Code (IRC) Section R408.4 requires access openings to under-floor spaces, either from the exterior or the interior.

If site conditions prevent exterior access, access must be provided from inside the building — typically through a framed opening in the main floor.

Why the Main Floor Framing Plan is Correct

Main Floor Framing Plan shows the joists, beams, and floor openings above the crawlspace.

The under-floor access opening (often between joists, covered by a hatch) must be framed into the main floor structure to allow entry to the crawlspace.

This plan will clearly show the location and framing details of the access hatch for contractor reference.

Why the Other Options Are Incorrect:

A. Second Floor Framing Plan — The crawlspace is not under the second floor, so no access opening would be framed here.

C. Foundation Plan — Shows foundation walls, footings, piers, and crawlspace layout, but the actual framed access opening is in the floor system above, not in the foundation drawing. The note about providing access might be referenced here, but the physical location and framing would be shown on the main floor framing plan.

NCARB ARE 5.0 PDD Study Guide References:

Content Area: Integration of Building Materials & Systems — Coordination between structural drawings and code requirements.

Code Reference: IRC R408.4 — Access Opening Requirements for Under-Floor Spaces.

Source References:

Architectural Graphic Standards — Crawlspace access detailing

Building Construction Illustrated (Ching) — Floor framing over crawlspaces