Retaining wall requirements are covered under Section R404.4 of the 2015 International Residential Code and 1807.2 of the 2015 International Building Code.
- Retaining walls less than forty-eight (48) inches in height measured from the bottom of the footing to the top of the wall that are not supporting a surcharge do not require a permit.
- Retaining walls over forty-eight (48) inches in height measured from the bottom of the footing to the top of the wall require a permit and must be designed by a registered design professional.
- Retaining walls up to forty-eight (48) inches in height are not required to be designed by a registered design professional as the most common manufacturers and products used in retaining walls (pave stone for example) have designs and charts available in their technical resources online. If the applicant shows a design using unusual materials that are outside of code (railroad ties or bags of concrete spiked in place, for example), then an engineer-sealed structural letter would be required at time of final inspection.