Mechanicals (Part 2)

Today I'm going to touch base on a misunderstood system in the new homes builders are constructing with the most recent code changes.  Radon systems are and are not considered part of the homes mechanical systems.  In the homes I build, I consider them a vital part of the homes ability to reduce moisture so I feel like they are much a part of the homes mechanical system.  In most homes built today, builders are only installing passive radon systems.  Therefore, they are not really part of the homes overall mechanical system. 

There are 2 ways in which the MN code allows builders to install the required systems.  The most simple and the most common system used by builders is to install a passive radon system.  By doing so, the builder is required to have either a vent-mat over clean sand in the sub-floor of a home or pea-gravel.  Both allow the radon gas to freely flow under the concrete slab of the home to a point where it can escape.  With this, the builder is required to run the vapor barrier under the concrete as well to the perimeter and overlap all of the seams.  They must also install a pipe that is typically run from the homes sump basket to the exterior of the home.  Most commonly, this pipe is run through the attic of the garage where it is more accessible in case a future fan needs to be added to the line to activate it.  With a passive system, the home relies solely on the theory the radon gas will just find its way out. 

The other and what I feel is the best solution is to install an active radon system to the home.  By doing this, I simply do what was mentioned above and add a fan to the pipe as it leaves the garage attic.  I have also added another item to our radon system which has greatly enhanced the benefits of the code requirement.  In the floors of our homes before the concrete is poured, I install drain tile lines that run every 15 feet through the center of the home as well as around the perimeter.  These exterior drain tile lines are run to the sealed sump baskets and the basket is what I've used to run the radon pipe to the exterior.  What I have found is that the added drain tile lines drastically helps cut down on the pressure in the sub-floor of the home which is a huge contributor to creating condensation.  Condensation is typically what makes a basement feel uncomfortable and colder than the rest of the home.  To me the radon system not only has the benefit of removing an unwanted gas, but also acts like a supercharged dehumidifier.  The other benefit I have found is that with a fan constantly running in the attic of the garage and constantly pulling air from the footings of the home, it creates a dryer foundation.  In reality, it creates a sponge factor in times of huge rain falls making it less likely to have water enter into the homes in such events.  A local inspector tried this system in his own home and the theory held true.  He had the active system running in his home for 3 years without his dehumidifier turning on.  He unplugged his radon fan and the dehumidifier started to run within days of turning off his system. 

Like mentioned in earlier blogs, if we can control temperature and pressure we can control condensation.  If we can control condensation we are on our way to a much more comfortable home.  Never hesitate to call or email with any added information needed.