Cost Effective Radon Reduction Begins with Floor Drains

Sealing sumps and floor drains is a cost-effective method of radon reduction.

  • Independent research shows sealing sumps and floor drains reduced radon levels by an average of 46%.
  • In many cases, reducing radon this much is enough to reduce levels to government guidelines.
  • You can achieve effective radon reduction for less than $100 compared to an ASD system costing $1500 to $2500.

The WHO Handbook on Indoor Radon / A Public Health Perspective states: “Passive systems of mitigation have been shown to be capable of reducing indoor radon levels by more than 50%. When radon ventilation fans are added radon levels can even be reduced further.”

Below are excerpts from two studies that measured radon reduction from sealing the basement floor drain in houses with catch-basin style drains.

The first excerpt is from a study that tested the efficacy of the Dranjer JN6 floor drain. It was a 30-day test before and after installation of the Dranjer. Table (4) is from that report.

Identifier 30-d result Bq/m3 Post Installation Bq/m3 RPD
W4 895 500 44%
W11 204 122 40%
W13 285 126 56%
W27 152 100 34%
W29 237 122 48%
W33 335 144 59%
W40 170 100 41%
Arithmetic Mean 328 173 46%

Warkentin P.M., Johnson Harry M, 2015. Winnipeg Radon Testing: Comparison of Test Durations, Effects of House Characteristics, and Efficacy of Flor Drain Seals. Journal of Health Physics, April 2015, Volume 108, number 4

The second excerpt is from a study that measured radon concentrations in the floor drain and tested radon reductions in the basement from simply sealing the floor drain.

The results of measurements of the radon concentration in the floor drain and in the basement air presented in table IV for a group of 7 houses. The radon gas measurements were taken using the Terradex Trach-Etch detectors.

As May be seen from the table, the radon concentrations in the floor drains were very high, ranging from 52.1 to 413.3 pCi/L, with an average 179 pCi/L. In each of the houses tested, the weeping tile was connected directly to the floor drain. Consequently the radon can migrate freely from the soil through the weeping tile and into it. If the floor drain is capped to prevent air flow from the drain into the basement, a substantial reduction in radon concentrations in the basement air would be expected. To determine if this reduction would in fact occur, tests were performed on 10 houses. The results of this remedial measure are presented in Table V.

As may be seen from Table V. in 8 of the 10 houses, the radon concentration dropped. There was on average a reduction of 46% in the radon concentrations in the basement air after the floor drains had been sealed.

Dumont RS. The Effect of Mechanical Ventilation on Rn, NO2, CH2O Concentrations in low-Leakage Houses and a Simple Remediation Measure for Reducing Rn Concentration. Transactions, Indoor Air Quality in Cold Climates: Hazards and Abatement Measures. In APCA Specialty Conference, Ottawa April 1985. IRC Paper 1383, NRCC 25994. P. 95