Dothan Crawl Space Guide: Codes & Licensing (2026)

Updated October 19, 2026. This guide is general information, not legal or engineering advice. Rules change, so confirm with the agency listed before you start work.

Quick reference

Topic	What to know	Source
Dothan building code	2021 International Residential Code, Ordinance 2024-343, effective Jan. 1, 2025	City of Dothan
Vented crawl space	1 sq ft of vent per 150 sq ft; 1 per 1,500 sq ft with a Class I ground vapor retarder	IRC R408
Sealed crawl space	Continuous vapor retarder plus exhaust, conditioned air, plenum, or a 70 pint/day per 1,000 sq ft dehumidifier	IRC R408.3
Contractor license	Home Builders Licensure Board license when residential work costs more than $10,000	Ala. Code 34-14A-2
Structural work	Unlimited license required when work affects structural integrity	HBLB Rule 465-X-1-.01
Home inspectors	Licensed by the Division of Construction Management	Ala. Admin. Code 355-17-1
Rainfall	About 54 inches a year; humid subtropical climate	Wikipedia (NOAA data)
Dothan soil series	Well drained; plinthite from 24 to 60 inches; slow permeability in lower layers	USDA NRCS

Why are Wiregrass crawl spaces damp?

Dothan's climate is humid subtropical, with hot, humid summers and roughly 54 inches of precipitation in an average year. The old approach of venting crawl spaces to the outside doesn't fit that climate well. The U.S. Department of Energy's Building America program notes that in humid climates, outdoor air is often more moist than crawl space air, which can bring moisture, mold and pest problems. Its research on sealed, conditioned crawl spaces found humidity reductions of more than 20 percent and heating and cooling savings of 15 to 18 percent compared with vented ones.

What about the soil?

The Dothan soil series, which the USDA describes as covering a large extent of the Southern Coastal Plain, has its type location in Henry County at the Wiregrass agricultural research station on Alabama Highway 134. It's classified as fine-loamy and well drained, but horizons with 5 percent or more plinthite begin 24 to 60 inches below the surface, and permeability ranges down to slow in those layers. For a homeowner, the practical takeaway is that water doesn't always drain away quickly below the surface, which is one more reason to cover the ground under the house. You can look up the soils on your own lot with the USDA Web Soil Survey.

What does Dothan's code say about crawl spaces?

The City of Dothan adopted the 2021 International Residential Code, including several appendices, by Ordinance 2024-343, effective January 1, 2025. Section R408 of that code covers under-floor spaces:

Vented crawl spaces generally need 1 square foot of net vent area per 150 square feet of floor, with an opening within 3 feet of each corner. With a Class I vapor retarder over the ground, that can drop to 1 square foot per 1,500 square feet.
Unvented (sealed) crawl spaces under R408.3 need a continuous vapor retarder over exposed earth, with joints overlapped 6 inches and sealed or taped, and edges run at least 6 inches up the stem wall and sealed. They also need one moisture-control method: continuous exhaust at 1 cubic foot per minute per 50 square feet, conditioned supply air at the same rate, use as a plenum where allowed, or dehumidification sized at 70 pints a day per 1,000 square feet.

Building Inspection Services administers the code for the city. Other towns and Houston County may follow different editions or requirements, so ask before work starts.

Which Alabama licenses apply?

Home Builders Licensure Board. Ala. Code 34-14A-2 defines a residential home builder to include anyone paid to construct, repair or improve a residence when the cost of the undertaking exceeds $10,000. The board's rules state that residential remodelers fall under that definition, and that when construction affects the structural integrity of a residence, an unlimited license is required.
Homeowner exemption. The law doesn't prevent people from working on their own residence, and owners acting as their own contractor on a home not offered for sale are exempt.
Home inspectors. Under Ala. Admin. Code 355-17-1, adopted under Ala. Code 34-14B, home inspectors must hold a current license from the Division of Construction Management.

Storms and crawl spaces

Hurricane Michael made landfall on the Florida Panhandle on October 10, 2018, as a high-end Category 4 storm, and a downed oak fell through at least one Dothan home, according to local news coverage. Severe storms and tornadoes also strike the Wiregrass, as Enterprise saw in 2007. After any storm, check the crawl space for shifted piers, broken framing and standing water, and remove wet insulation before resealing. The HBLB recommends verifying a contractor's license before hiring for repairs.

Questions to ask a crawl space company

Where is the moisture coming from, and what gets fixed first?
Which R408.3 moisture-control method do you recommend, and why?
Does my address need a permit, and who pulls it?
What's your HBLB license number, and is it limited or unlimited?
What maintenance is required, and what does the written warranty cover?

Common questions

What building code does Dothan use for homes?

The 2021 International Residential Code, adopted by Ordinance 2024-343 and effective January 1, 2025.

When does an Alabama contractor need a license for crawl space work?

When the cost of residential construction, repair or improvement exceeds $10,000, a Home Builders Licensure Board license is required. Structural work needs an unlimited license.

Does the code require a dehumidifier in a sealed crawl space?

Not specifically. The 2021 IRC requires one approved moisture-control method, and a dehumidifier sized at 70 pints a day per 1,000 square feet is one of the options.

Dothan crawl space guide (2026)