106.1 - Permit Required for Closed Crawl Space

Permit Required for Closed Crawl Space

Code: 2018 Administrative Code and Policies

Date: December 11, 2025

Section: 106.1

Question: Are permits required for the conversion of a conventional crawl space with wall ventilation openings to a crawl space by Section R409 of the 2018 North Carolina Residential Code (NCRC)?

Answer: Yes.  2018 NCACP, Section 106.1 states that a current permit is required for all work described in the technical codes (2018 North Carolina State Building Code) unless specifically exempted by the North Carolina General Statutes (N.C.G.S.) or the technical codes. Permit requirements are addressed in more detail in N.C.G.S. 143-138 (b5) and 160D-1110(c), which states that no permit is required if the work is in a single-family residence, farm building or commercial building and the cost of the work is $40,000 or less.  Specifically, N.C.G.S. 143-138(b5)(3) and 160D-1110(c)(3) lists an exception which states that if any of the work includes an addition, replacement or change in the design of heating, air conditioning, or electrical wiring, appliances, or equipment, other than a like-kind replacement of electrical devices and lighting fixtures, a permit is required regardless of the cost of the work.

One of the requirements of a closed crawl space is that moisture levels in the crawl space shall be controlled.  Moisture vapor control shall be provided by one of the following, as listed in 2018 NCRC R409.5:

1)           A permanently installed dehumidifier with a condensate pump or drain and an electrical outlet.

2)           Ducting supply air from the dwelling air conditioning system.

3)           Blowing house air to the crawl space with a fan.

4)           Installing an exhaust fan

5)           Designing the crawl space as a heated and cooled conditioned space.

All the moisture vapor control options listed above involve some level of addition or change that triggers the application of N.C.G.S. 143-138(b5)(3) and 160D-1110(c)(3).

To summarize, a permit is required for this application when either of two conditions are met within N.C.G.S. 143-138 (b5) and 160D-1110:

1)           When the cost of the work is more than $40,000.

2)           When any of the work includes an addition, replacement or change in the design of heating, air conditioning, or electrical wiring, appliances, or equipment, other than a like-kind replacement of electrical devices and lighting fixtures.

Since the work described in 2018 NCRC, Section R409.5 triggers application of N.C.G.S. 143-138 (b5)(3) and 160D-1110(c)(3), a permit is required to convert a conventional crawl space to a closed crawl space regardless of cost under a single permit per NCGS 160D-1110(d)(2). The single permit per NCGS 160D-1110(d)(2) includes building, mechanical and applicable electrical inspections itemized under the single permit.