The risk of Vapor Intrusion (VI) occurs when there is the potential of a migration of petroleum products or volatile chemicals from contaminated groundwater, soil or a vapor plume into an overlying building. Petroleum products and volatile chemicals in the vapor phase may migrate through subsurface soils into indoor air spaces in ways similar to that of radon gas seeping into homes. These chemicals may include volatile organic compounds and select semi-volatile organic compounds, as well as some inorganic analytes.



Worker spraying vapor barrier

After assessing of the vapor concentrations below a building and determining that a potential for vapor intrusion into a structure is realized, there are two possible paths for addressing this risk. The first is risk profiling through more sampling and analyses. The second is the installation of a mitigation facility. VMS will guide you through these two paths to develop the most cost and time-effective strategy for you.

In certain instances, risk profiling may be the lower cost solution to addressing potential VI risk. However, while it may be cost-effective, it may also be time prohibitive, requiring multiple site assessments, data analysis, reporting and consulting. These factors may greatly lengthen the time required in completing a real estate development project. This path may also lengthen the time required in solving an immediate question of safety to building occupants where VI is determined to be a potential risk.

Types of Chemical Vapor Barriers used in VI Mitigation

vapor barrier material chart

The second path VMS utilizes is a chemical vapor barrier that is a composite membrane system. This solution takes the advantages of chemically resistant, high-density polyethylene and combines it with the benefits of spray-applied membranes. Below the vapor resistant membrane is a venting system, which is designed for the footprint of the building. This venting system allows the chemical vapors held back from migrating into the building by the vapor membrane barrier to be vented out of the sub-slab of the building through a vent pipe and away from the building and its occupants. The combination allows VMS to offer a system that is designed specifically to mitigate contaminant vapor intrusion for new structures.

What if you are presented with the need to protect occupants in an existing building where it is infeasible to install the two-tiered chemical vapor barrier described above? VMS also provides a solution for existing structures whose sub-slab vapor is contaminated and the potential for VI has been determined. VMS can install an engineered sealant product specifically designed to repel the transmission of sub-slab vapor. This product has been rigorously tested and has proved to substantially reduce the influx of harmful vapors into an overlying building.

Our chemical vapor barriers have been accepted by state environmental agencies, branches of the military and environmental consulting firms around the world.


Have you been recently given a job that calls for some type of chemical vapor barrier? We have experts who work closely with contractors in order to deliver the perfect, most cost-effective vapor mitigation solution based on the required specs.



We offer architects our knowledge and experience in vapor mitigation as consultants. Our team at Vapor Mitigation Strategies will sit down with you and review environmental reports and work with you on the development of the scope of your project.



Washington Child Care Center Mitigates Risk of Vapor Intrusion

Luckily, awareness about vapor intrusion has grown in recent years. Recently the Environmental Protection Agency (EPA) specified vapor intrusion as a potential pathway in its Superfund Program, designed to fund the clean-up of uncontrolled hazardous waste sites. The program resulted from the passage of the Comprehensive Environmental Resource Conservation and Recovery Act (CERCLA) in the early 1980s.

New Bank Site Includes Vapor Barrier System

Before completing construction of the new facility, the owner opted to have a chemical vapor barrier installed as a preventive measure. This decision was made because improper handling, previously unregulated disposal, or accidental spills and leaks of these car service chemicals may have introduced themselves into the subsurface where they emit toxic gasses into the soil vapor.


Want to know a little more about how we can help you and your team? Give us a ring or fill out our contact form to learn more.


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