Mitigation with a Radon Hot Spot - American Radon Mitigation

Mitigation with a Radon Hot Spot

How do you reach a radon hot spot where you can’t run a pipe? It is possible, as long as you have the correct information. If you’re familiar with our work, you know that we use pressure field extension testing on every home. This helps ensure that our systems work effectively and efficiently, even in those difficult-to-mitigate houses. In this article, we’ll show you how we used pressure field extension testing to reach a radon hot spot in an area that was difficult to reach.

What is pressure field extension? 

Pressure field extension, or PFE, refers to the strength and span of suction a radon mitigation system creates under the house. For a system to be effective, it needs to create a certain amount of suction under every area of the home. That will ensure the system draws in the radon-laden air, so it doesn’t enter the home. During every install, we perform PFE testing, which involves measuring the amount of negative pressure the system creates under different sections of the building. 

Pressure Field Extension

The House: How we mitigated this home with a radon hot spot

The house we’re looking at today is a 1948 rambler with an initial radon level of 13.4 pCi/L.  

1948 Rambler Radon Mitigation Project

When we bid this house, we made an interesting discovery. In the basement, we noticed a piece of plywood on the wall. The homeowners didn’t know what was behind it, so we decided to find out.  

What is behind the plywood?

When we removed the plywood, we uncovered a dirt-floor well room. Areas open to the soil are significant radon-entry points, so we placed an EcoTracker radon monitor in the well room for the rest of the bid. In that short time, readings reached 26 pCi/L and were still climbing when we left. 

Dirt-floor Well Room

The well room would significantly affect how we approached this project. However, it was in a difficult-to-reach spot. The basement had two unfinished areas divided by one large finished living area. From a PFE perspective, putting the suction point in the well room would make sense. However, it was directly beneath their first-floor living room, so we didn’t have a good place to run the exhaust pipe.  

There wasn’t an attached garage, and the owner didn’t like the aesthetic of an exterior radon system, so we had to find a way to run the fan up through the house and still treat the well room. We wouldn’t know the best course of action until we performed pressure field extension testing, so we devised a 4-phase plan. We would start with phases 1 and 2, then move on to phases 3 and 4 if PFE indicated it was necessary. 

 Phase 1: Seal the Well Room 

Sealing improves PFE and can help prevent radon from entering the home. For example, in the well room, we could see the block openings were open to the rim joist area, allowing the house to draw in radon and distribute it to other areas of the house. So we foamed the block tops and cracks, placed an EcoTracker inside the room, then taped the plywood cover back on so we could still access the room. At one point, we saw radon spike to 100 pCi/L, which maxed out the monitor. For reference, the EPA recommends mitigating anything above 2 pCi/L. 

Sealing improves PFE

Radon Spikes

 Phase 2: Main Suction Point 

Next, we used pressure field extension testing to determine where to place our main suction point. We decided on the unfinished area opposite the well room. There, we placed the suction point next to the plumbing. There’s usually a lot of settling next to the plumbing, which makes it easier to pull air. We could also run the exhaust pipe up through a closet on the main level. After installing our main suction point, we conducted our PFE test again. As we suspected, it barely affected the pressure in the well room. To reach the well room with one suction point, we needed an overpowered fan, which would’ve been noisy and expensive to run. We moved on to Phase 3. 

Suction Point 1

Run exhaust pipe up through a closet to exhaust out of the home

 Phase 3: Second Suction Point 

We needed to add another suction point to make an effective and efficient system. We placed this one in the same unfinished section as our original suction point. However, this one was next to the finished living area and more centrally located, so we hoped we could reach the well room without going through the finished portion of the basement.  

Second Suction Point more centrally located

We reran our PFE test and created -4 Pa of pressure next to the well room. Based on those readings, we were confident that the system would effectively lower radon with just those two suction points. 

We ran pipe for our second suction point along the ceiling, tied it into our main suction point, routed up through a closet, and exhausted out through the roof. 

Tied second suction point into the first

Routed up through a closet and exhausted out through the roof

Phase 4: Running Through a Finished Area 

Thankfully, we could reach our target PFE with Phases 1-3, so we never needed to implement Phase 4. However, if that second suction point hadn’t been enough to reach that far corner, we would have required another suction point to treat the well room, which would mean finding a way to run through the finished area of the basement. We had two options.

One, we could run a pipe across the ceiling through the basement living room. However, to do that without visible pipe, we’d have had to demo parts of the ceiling, which is a big, expensive project.  
Wanting to avoid pipe running through the living room

Our second option would have been to stitch through the living room. Stitching involves drilling holes along the floor to dig a tunnel for airflow. In areas with carpet, we’re able to pull up the carpet, stitch, seal the holes, and put the carpet back so that it’s undetectable. We typically only stitch when we have to run through finished areas. In this instance, we would have stitched across the living room, then picked back up with pipe once we hit the unfinished section where the well room was located. 

Used stitching to move air through finished area

Wrap-up: Results of mitigation in a home with a radon hot spot

By sealing the well room and installing a mitigation system with two suction points, we achieved our goal PFE with a small radon fan, the Fantech Rn1. The equivalent would be the RadonAway RP 140 or the Festa Spirit. After the system ran for about a day, our EcoTracker readings fell to 0.5 pCi/L. Thanks to PFE testing, we created a quiet, energy-efficient system that significantly reduced radon levels. We also determined that we did not need a third suction point in the well room, which saved time and money. 

As you can see, PFE testing provides valuable information for the radon mitigation process. We run diagnostics on every home to ensure a quality system for you and your family. If you’re looking to reduce radon as much as possible without excessive energy costs, contact us to set up an estimate.