Accumulation of volatile organic compounds (VOCs) that migrate inside buildings from underlying contaminated soils and groundwater poses human health risks. VOCs intrusion into buildings driven only by diffusion was reproduced by a laboratory-scale experiment. Effective diffusion coefficients and fluxes of a group of selected chlorinated solvents and BTEX through two types of isolation material – that is, concrete (anhydrite screed) and geo-membrane – were estimated. The laboratory experiment indicated that the diffusive transfer of pollutants through sediments into indoor air of buildings cannot be prevented by building sealing material, but it could be attenuated to a certain degree by concrete and up to non-detectable levels by the geo-membrane. Effective diffusion coefficients through concrete and geo-membrane ranged from 3.17 × 10−2 to 5.90 × 10−5 cm2/s and from 5.47 × 10−6 to 5.50 × 10−8 cm2/s, respectively.