How does a radon mitigation system work?
Most homes are treated for high radon levels using what is known as a sub-slab mitigation system. The principle is simple: evacuate radon-laden air from under the basement, floor slab, or crawlspace before it has the chance to enter your home. To accomplish this, we install a fan system that is as effective as possible and as aesthetically pleasing to the home as possible. To learn more about how a typical system works, proceed below.
|
|
|
|
|
Step 1: Planning & Measurement The first thing we do is examine the home and determine the potential suction point for the system and the potential route for the suction pipe. We then will place several small test holes, one in the location of the potential suction point, and a smaller one in an area away from this point. Using a micro-manometer and a shop vac, we can see if there is "communication" of air between the suction point and the measurement point. This early measurement can tell us much about the condition of the material underneath the concrete slab. |
|
Step 2: Drill the Hole Once we're satisfied that we have a good suction point, we drill a hole in the concrete slab. This hole is generally 4" in diameter to accomodate 3" PVC piping. However, we may determine during the planning & measurement phase that 4" PVC piping is needed. In that case, we'll drill a 5" diameter hole. Once we're through the concrete, we'll clean 2 gallons or more of gravel and/or soil creating a dry sump pit below. |
|
|
Step 3: Rout the suction pipe Now, based on what we decided during the planning phase, we'll rout the suction pipe either to a hole drilled into an exterior wall for an exterior mount or up through the ceiling to a closet or other suitable chaseway into the attic. We'll place a custom pickup pipe into the suction hole, and seal around the pipe making an air-tight and water-tight seal. In the photo at left, note that this particular home had 3 separate slabs, so we made a penetration into each off of a main trunk line. For crawlspaces, we'll install a sealed vapor barrier with one or more pickup points underneath to draw air in the same manner as with a sub-slab setup. |
|
Step 4A: Exterior Fan According to EPA guidelines, the system fan can be placed on the exterior of the home or in an attic. The fan should never be placed in the basement or in a living area. If the plan is for an exterior mount, we'll attempt to locate the fan on the "utility" side of the house, or in an area as hidden from view as possible. In the photo at right, we were able to place this fan with other utility items such as an AC condenser and electrical meter. A switch will be located outside, next to the fan for any future servicing or replacement. |
|
|
Step 4B: Attic Fan
If the better route for the pipe is into the attic, we'll do our best to place the fan in a location where it can exhaust on an unseen side of the house. We'll also take into consideration what is below the fan and try to locate it away from sleeping areas. even though the fans we use are very quiet. We take every precaution we can to insure you don't know the system is there. The pipe and fan will be properly supported and there will be a switch next to the fan to allow for servicing or replacement. |
|
|
Step 5: Venting The final component of the system is the vent pipe. With an exterior fan, the vent pipe is generally constructed using downspout that matches the downspout already on the house. In the photo at left, you can see that the vent extends to the edge of the roof line. This is important to prevent any backdrafting of radon-laden air into open windows. With an attic fan, a 3" or 4" PVC pipe is placed through the roof using a minimally sized hole, and the pipe is booted just like a plumbing vent pipe. |
|
|
Step 6: Labeling & Monitoring The last step we perform is we install a U-tube manometer on the piping near the suction point. This gauge tells us and you a great deal about how your system is working. The gauge shows how much vacuum the system is drawing, measured in inches of water column. For a typical installation with an RP145 fan, we expect to see between 0.5" and 1.5" on the gauge. Generally, the more porous the material under the slab, the lower the reading meaning that more air is flowing under the slab to the suction point. For you, the homeowner, the main thing you're looking for is that the two sides of the gauge are not both at the 0" mark. If they are, then the system is not on or something is wrong with the operation. We place a label right beside this gauge with our phone number so you can call us right away. |
The Little Things
So, in a nutshell, that's a typical radon mitigation system. But all systems are not the same. Little Creek Home Services is committed not only to reducing the radon levels in your home, but also to building a quality, integrated system of your home that is constructed with quality materials and will last well beyond the 5 year warranty period.
RadonAway fans & materials
We use fans and accessories from RadonAway. RadonAway is a leader in the radon mitigation industry and has been providing high quality radon products for over 25 years. Their fans offer a 5 year manufacturers warranty and are designed to serve far longer. To learn more about them, visit www.radonaway.com
Exterior appearance
Let's face it, a radon fan on the exterior of your home isn't going to help you win any neighborhood awards, but there are ways to make the system more attractive. We use white couplers and match the downspout as closely as possible to other downspouts on your house, even painting them when necessary. Fan switches are placed near the fan in weatherproof boxes with weathertight conduit and connections. And if a fan just stands out too much, we can cover it either with a manufactured cover, or one we make ourselves to match. We can also install a square style fan in certain cases to look more like a utility/electrical box and less like a fan.
Downspout painted to match
|
Custom fan cover at log cabin
|
Square fan
|
Interior Appearance
Generally, the interior pipe is placed in a utility room or other unfinished area. We always strive for a clean and plumb install. Occasionally, we have to put the interior pipe in a finished area of the home. In these cases, we do our best to minimize the impact of the piping.
Generally, the interior pipe is placed in a utility room or other unfinished area. We always strive for a clean and plumb install. Occasionally, we have to put the interior pipe in a finished area of the home. In these cases, we do our best to minimize the impact of the piping.
Neat, clean piping
|
Before & after of an interior drop - a custom cover was made and installed that is easy to move for checking on the system pressure.
|
For systems with multiple suction points, every effort is made to route the pipe out of the way of any current activities as well as any future repairs to other systems.
|
Hopefully, this information has helped you understand a little better how a radon mitigation system works and how we go about installing one in your home. If you have questions or would like a quote, please contact us by phone or email.
Here is a link to a great video by RadonAway that covers the entire process: https://youtu.be/rHGIsA2MfdI
For even more information on radon, click the links below.
Radon is Real
www.radonisreal.org
|
Little Creek Home Services
Jason Cooper Certified Home Inspector #3380-000609 Radon Measurement Specialist #15SS007 Radon Mitigation Specialist #15G005 Class C Contractor #2705156166 6181 Grassy Hill Road Boones Mill, VA 24065 540-798-0238 littlecreekhomeservices@gmail.com |