If your home was built before June 2009, you’ll likely need a drain tile depressurization (DTD) or sub slab depressurization (SSD) radon reduction system. This is also referred to as active soil depressurization or ASD. Both are active radon mitigation systems. They create a vacuum under your home that gives the radon an escape route.
Drain tile depressurization utilizes existing drain tile (perforated pipe) below the concrete floor of your home to create an easy path to pull the radon gas into the mitigation system. A sub-slab depressurization system works by creating suction in a void created below the floor to draw the radon-laden soil gas into the radon system.
DTD systems are typically very effective at reducing radon concentrations and often the easiest and least expensive systems to install. One drawback to a home with drain tile is we often have to seal many air leaks. These leaks are usually found where the concrete floor meets the foundation wall and at the tops of concrete block walls. If the basement is finished it makes it hard to seal air leaks. A radon fan that can move a lot of air may be needed. These high-flow systems come at a price, including the extra cost to run a bigger radon fan and the loss of conditioned air (air you are paying to heat and cool) that is drawn into the radon system and exhausted outside.
Here’s a look at American Radon Mitigation’s DTD installation process:
- We start by sealing cracks and openings in the floor. If you have block walls, we’ll seal any openings in the top of the block. If your sump basket cover can’t be sealed, we’ll install one that can be. Sealing makes a radon system more efficient and effective.
- Next, we’ll figure out the best spot to put the suction point based on your preference and the route out of your home.
- We then core a 5-inch hole through the concrete floor, being careful to collect all of the dust to keep your home clean.
- Once the hole is created, we remove 5 to 20 gallons of material to create a collection point.
- Next comes more diagnostic testing to determine if additional suction points are needed, if the drain tile should be tied into, how much air we need to move, what size pipe to build the system out of, and which radon fan will be best for your home.
- Then we install the vent pipe that is either routed out the side of your home, into the garage, or up through a closet and into the attic.
- We then do more diagnostic testing to be sure the fan we select is going to operate efficiently and within its operating range.
- Then the vent pipe continues from the radon fan and out through the roof.
If your home doesn’t have a drain tile system, then we’ll install an SSD system. The function of an SSD system is similar to that of a DTD system. However, instead of running collection points through a drain tile system, we drill directly into your home’s concrete floor.
SSD systems often require more suction points than DTD ones do. Our extensive diagnostic process will help us determine the number of suction points required to create a vacuum under your home. Most SSD systems also require a high-suction fan to effectively and efficiently remove radon from your home. Since they’re more complicated to test and design, SSD systems are often more expensive than DTD ones.
With any active radon mitigation system, the key to getting your levels low is creating a vacuum under your entire home. The only way to know if we’re achieving this is to take the time to do the diagnostic testing. In other words, if we create a suction point in the mechanical room in the basement, is the vacuum under the home reaching the bedroom on the other side of the basement where your kids sleep?
Knowing Your Active Radon Mitigation System Is Working
We install a U-tube manometer that measures the suction of a fan. If the fluid levels in the U-tube are different, the radon fan is on. If the fluid levels are equal at zero, the fan is not working. You should call for service. In addition to the manometer, we offer a low airflow alarm that starts to beep within 30 seconds if the airflow in the pipe drops, indicating a problem.
We also provide you with a post-mitigation radon test kit to ensure the radon levels have dropped. This test can be started 24 hours after the system has been turned on.
If you sign up for one of our service plans, we send you out a long-term test kit every year to ensure your radon levels stay low.