Maryland Building Code Retaining Wall Requirements

Through Public Safety Article 12-503 and COMAR 05.02.07, Maryland adopts the International Residential Code (IRC) and International Building Code (IBC). IRC R404.4 requires a building permit for any retaining wall over 4 feet measured from the bottom of the footing to the top of the wall, or any wall supporting a surcharge such as a driveway or structure. Walls of these dimensions must be designed by a licensed engineer. Drainage, frost depth (30 inches in most of Maryland), and lateral soil pressure calculations apply. Local governments enforce permits and inspections but cannot waive the engineered-design threshold.

Building without a permit triggers stop-work orders and double permit fees. Walls failing to meet code may require demolition or retroactive engineering review.