Huntsville Basement Finishing Guide: Radon, Karst Ground and Permit Costs

A free cost and process guide for homeowners in Huntsville and the rest of Madison County, from Get Basement Pros.

Before you finish: radon and ground

Two facts about Huntsville's ground shape any basement project. The Alabama Department of Public Health names 15 counties, Madison and Limestone among them, as having the highest potential for elevated radon. And the Geological Survey of Alabama says many areas of north Alabama are underlain by carbonate rocks such as limestone that dissolve and form caves and sinkholes, with triggers that include drainage problems and excessive rainfall. Both should be dealt with before any drywall goes up.

Step 1: Test for radon

The Alabama Department of Public Health notes that radon levels can differ greatly even between neighboring homes, recommends that all homes be tested, and points to fixing homes at or above 4 pCi/L. Test the lowest lived-in level before you finish it. If mitigation is needed, it is easier and cleaner to install before walls are finished.

Step 2: Solve water and drainage

Look for damp walls, white mineral deposits, musty smells and water near the floor drain. Fix gutters, downspouts and grading first. Because drainage problems are a sinkhole trigger, make sure water is carried well away from the house, not dumped beside the foundation.

Step 3: Permit costs

The City of Huntsville calculates residential building permits other than new houses as the total contracting price times 0.0055. A detailed contract therefore also sets your permit cost. Trade work, such as wiring, plumbing for a bathroom or new ductwork, is permitted by the contractor holding the license for that trade.

Step 4: Licensing

In Alabama, building, remodeling or repairing a residence when the job costs more than $10,000 needs a license from the Home Builders Licensure Board. Most basement finishes are above that. Ask which license your contractor holds and look it up.

Step 5: The order of work

1. Water management and any structural repairs. 2. Radon testing and mitigation. 3. Design, including egress for bedrooms. 4. Permits. 5. Framing with moisture separation from concrete. 6. Rough electrical, plumbing and HVAC. 7. Rough-in inspections. 8. Insulation and drywall. 9. Below-grade-rated flooring, trim and fixtures. 10. Final inspection.

Humidity control

Below-grade rooms in Huntsville's humid summers need dehumidification. Ask whether the HVAC plan will condition the space properly, or whether a dedicated dehumidifier is needed.

Comparing quotes

Ask for line items: drainage or waterproofing, framing, insulation, electrical, plumbing, HVAC, drywall, flooring, egress windows, permits and cleanup.

Records

Keep the radon test results, permits, inspections and warranties together. Radon results are useful when you sell.

Sources for this guide

The City of Huntsville calculates residential building permits other than new houses as the total contracting price times 0.0055. For a new single-family house it multiplies heated square footage by $15.00 and unheated square footage by $7.50, adds the two, and multiplies the sum by 0.0055. Source: City of Huntsville, Permit Costs
The Alabama Department of Public Health names 15 counties, Madison and Limestone among them, as having the highest potential for elevated radon. It notes that levels can differ greatly even between neighboring homes, recommends that all homes be tested, and points to fixing homes at or above 4 pCi/L. Source: Alabama Department of Public Health, Radon in Alabama
The Geological Survey of Alabama says many areas of the state, particularly north Alabama, are underlain by carbonate rocks such as limestone that dissolve and form caves and sinkholes. It lists sinkhole triggers including a drop in the water table from drought or nearby well pumping, heavy construction or weight at the surface, drainage problems and excessive rainfall. Source: Geological Survey of Alabama, Sinkholes
In Alabama, building, remodeling or repairing a residence when the job costs more than $10,000 needs a license from the Home Builders Licensure Board. A limited license, which needs no exam, covers only a single-trade job contracted directly with the homeowner that does not affect the home's structural integrity; other jobs need an unlimited license, which requires passing skill and business-and-law exams. Source: Alabama Home Builders Licensure Board, On The Level newsletter

Sources checked 2026-10-26. Every cost figure on this page comes from a source named above; fees and rules change, so confirm current amounts with the office that sets them before you budget.

More for Huntsville homeowners: Basement in Huntsville, AL.