What’s the difference between a vapor encapsulation system and a radon system?

One system is designed to trap water under your home while the other is designed to remove all soil gasses–including water vapor–from below your home.  A vapor encapsulation system can cost over $10,000 but a radon crawlspace system is usually closer to $2,000.  Why is one system five times the cost of the other?  In short: consumer awareness and industry momentum.

Since most radon systems are installed as a result of a real estate transaction, they’re often done as cheaply as possible.  If you’ve read my radon and real estate page, then you know one of my “DON’Ts” is “don’t let the seller install the radon system”.  This is because the seller has little incentive to get a quality contractor that will make the system work well for the life of the home they are moving out of.  They simply want the house to pass a 48 hour radon test, collect their check, and move on.  The buyer is the one that will live with the ongoing costs of the radon system like repairs for sub-par work or energy costs from an energy-hog fan.  Vapor encapsulation, on the other hand, is often a buying process that is initiated by a homeowner.  Perhaps they want to use their crawl space for storage, or they have had a mold issue in the past that has caused health or financial issues.  These consumers want to install a system to protect from moisture and all its risks for a home they’ll be in for many years to come.

Bottom line: homeowners know to be afraid of water in the home and will pay to be safe; but they rarely know to be afraid of radon and are skeptical of all costs to mitigate it.

encapsulation vapor barrier
One encapsulation industry rep commented: the “encapsulation industry” is driven by residential code (IRC). This is for both new construction and retrofit, with the latter being the driving force. The encapsulation industry was really born from the effects of “code” level work not being sufficient. This is why we see so much more progressive and advanced retrofit work. They understand that code level work is not enough. During our trainings we refer to the code as, “the bare minimum legally allowable to not get in trouble”....You will see there is not mil or performance specifications in the residential code for vapor barriers. This is something we have been fighting for years and slowly changing. We first saw the change in the commercial world adopting the ASTM E 1745 standards and then residential codes for under-slab applications. We expect this to change soon too, but as you know it is always a slow process.

Why is a proper radon system better than a vapor intrusion system?

AARST/ANSI standards for sub-membrane radon systems are actually higher than vapor encapsulation standards.  That’s because the vapor encapsulated industry doesn’t have a national standard they adhere to.  Radon standards call out the permeability of vapor barriers, adhesion, installation techniques, and more.  However, many states and municipalities do not have consumer protection laws for radon in place.  Those that do have laws on the books often do not have code officials enforcing them properly, which leads to corner cutting.  Market pressure in vapor encapsulation–however–is led by educated homeowners that want to prevent water and its risk to their home and their family.

A radon fan can actually move up to 15 gallons of water vapor per day, which means it dries out your soil 24/7/365.  A vapor encapsulation system only works to block it out.  When you have a radon mitigator install an AARST/ANSI system with a high-quality vapor barrier, you can often get a system that is better for moisture and 1/10th the cost.  Crawl space radon mitigation systems, or sub membrane depressurization systems, are one of the best investments you can make for your home equity and family’s health.

This is a closeup of the quality crawlspace barrier we have on offer at our official PDS Radon Supply store.


I predict within my lifetime, these two industries will have melded into one: taking the best from both worlds.  In fact, it appears AARST is doing just that.  Our annual industry event is being attended by more and more vapor specialists that deal with other soil gasses and contaminants outside of radon.  They teach our industry what the consumer is looking for while we show them simple changes they can make to protect their customers from soil gasses like radon.  Contractors and homeowners will look back on this time years from now with curiosity.  Why’s that crawl space look like that?  Well hopefully I provided a bit of context for you curious “future googlers”.

Protect your home from soil the dangers of radon and other harmful gasses with our high quality premium crawlspace barrier.