Why is sealing important for radon mitigation?

Did you know that sealing is a critical step in creating an effective and efficient radon mitigation system? Sealing gaps and cracks helps create a better vacuum under your house and reduces the number of places for conditioned air to leave. That means sealing not only helps your system work better, but also saves you money over time.
If we had not sealed, this system would cost about $414 a year to operate. After sealing, we estimate the system will cost about $184 a year to operate. That's a savings of $230 a year! This customer should start to see a return on their investment in just over two years.
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We receive a trainer discount on TEC products. All opinions are our own.
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Feel free to reach out to us at www.americanradonmitigation.com/ or 612-474-1004.

[@interfaceonly]

Very thoroughly put together! 👍

[@AmericanRadonMitigation]

Thank you, Spencer!

[@paulkelm6550]

Nice work! Thank you.

[@AmericanRadonMitigation]

Thank you, Paul!

[@zirokl]

great content, you have all the answers for this topic.

[@AmericanRadonMitigation]

Thank you, Andriy! I don't have all the answers, though. What I do have is an excellent network of people that are willing to teach me.

[@JuanYoga]

Really helpful, thanks Jesse!

[@AmericanRadonMitigation]

You betcha, Juan!

[@Trentfully]

Thanks !

[@AmericanRadonMitigation]

You bet!

[@philippebelair3372]

Always interesting to hear from you A+

[@AmericanRadonMitigation]

Thank you!

[@BrunoVassel]

Thanks for sharing! Why insulate the pipe in the garage?

[@AmericanRadonMitigation]

Good question, Bruno! Here are the benefits of insulating the pipe in an unconditioned space like a garage or attic. 1. Reduced noise. 2. Reduced condensation both inside and on the outside of the pipe. Condensation on the outside of the pipe can drip on insulation, drywall, or other items. Condensation can also allow mildew to accumulate on the piping. 3. Dramatically lessen the chances of ice accumulation in the piping. If the system gets blocked with ice, radon levels will rise until the system thaws out. This is the main concern here in Minnesota. Check out section 6.2.10 in the standard for more information. standards.aarst.org/SGM-SF-2017/20/index.html

[@BrunoVassel]

@@AmericanRadonMitigation Fantastic answer! Thanks for sharing. We have done thousands of garage installations here in Utah. My guess is we are dealing with completely different climates. It obviously is dryer here than where you are installing. We have luckily not had any issues with sweating pipes. Garages are colder than the house of course during the winter months, but we don't see garages getting to freezing levels. They stay above that so is there really an icing concern in a garage install?

[@AmericanRadonMitigation]

You're welcome, Bruno. I worked on a system in LaCrosse, Wisconsin back in February. We had a long cold snap during that time. The system had 13 feet of horizontal pipe in the garage attic that slowly froze solid while I was troubleshooting the system another company had installed for her. So yes, it is an issue, especially if there is horizontal piping. Her home was a twin home. The neighboring unit also had a radon system. While I was on the roof, I noticed that the neighbor's radon exhaust was blocked with ice where it discharged through the garage roof.

[@wede1993]

How thorough you are is appreciated! What do you do when there are drain tiles with dimple mat plastic leaving gaps along the edge of basement walls that can't be sealed? And if they're drawing air like it seems like they would, how severe is the energy loss from the house if conditioned air is being sucked out?

[@AmericanRadonMitigation]

The energy penalty can be significant if you do not seal the dimple mat and use a large radon fan. I ran the numbers on this scenario in a home a few years ago, and it would have cost over $1000 a year to operate. The cost breakdown was $172 to power the radon fan and over $800 in added heating and cooling costs. If it's necessary to leave the dimple mat unsealed to allow water entry, I recommend installing a vapor barrier on the foundation wall. Tuck the bottom of the vapor barrier between the foundation wall and the dimple mat. Then, seal the top, seams, and bottom of the barrier to limit conditioned air loss. You may also have to seal the top of the foundation wall if it's a concrete block. The vapor barrier will allow water to run down the foundation wall and enter the water management system.

[@wede1993]

@@AmericanRadonMitigation that’s a fantastic breakdown and solidified my concerns. Thank you very much for the detailed information!

[@AmericanRadonMitigation]

You bet!

[@blairhenderson9188]

Thank you Jesse, extremely helpful. I have a question for you... I would like to completely seal my basement floor prior to coring and running pipes. I have the Radon calking for the cracks but I would like to paint entire floor as well. Can you recommend a paint/sealant that is durable and will harden to a permanent seal?

[@davidstevens1911]

SaniTred. Coating claims to be the best. Google them.

[@AmericanRadonMitigation]

Sorry, I don't have any recommendations for that.

[@BrensBoutique]

Hi Jessie. We have a system that is in our basement where the vent pipe comes up through the garage, much like the one shown here. Ours is not covered though and is just the white piping. The pipe is covered in a greasy looking dirt that looks like some might be mold. Is this normal and is there a safe way to clean this pipe? The system shows it's working great but the pipe looks very unsightly in our garage!

[@AmericanRadonMitigation]

Hey Bren. The problem you are describing is caused by condensation forming on the outside of the piping. You can clean it off with a cleaner like Simple Green. To prevent mold and mildew in the future, you can install insulation with a vapor barrier over the piping in the garage and in the garage attic. Since that would involve cutting the pipe apart, you may want to try wrapping the piping with sill sealer instead. A mitigator in our area uses it to insulate the piping in their systems. Sill Sealer - amzn.to/3k3hkXC Check out section 6.2.10 in the mitigation standard to see what it says about pipe insulation. standards.aarst.org/SGM-SF-2017/20/index.html#zoom=z We plan to cover mildew on radon piping in a future video but need some photos or a video to use as an example. Would you be willing to send us some pictures and or a video showing the piping? If so, horizontal 16:9 photos work best as well as horizontal video. You can fill out or estimate request and let us know you want to send photos, and we'll provide you an email address to send them to. Thanks, Bren! americanradonmitigation.com/free-estimates/

[@Messenger67]

I've been watching your content for a while, I have a problem with Radon in my MI home, I feel like I could get certified in Radon mitigation systems after all my troubleshooting and your videos. Have you ever used the concrete sealer called RadonSeal?

[@AmericanRadonMitigation]

I’m glad you found them helpful! I have never used RadonSeal or heard of anyone using it, so I can’t give you any insights about the product or it’s effectiveness.

[@toxic5628]

Do you know if there is a RADON barrier to put under laminated floor. I found barriers for under the slab, but if the house is already build what can you recommend for on top of the slab. I have to change the flooring and will install laminated floor. What I read about the normal vapor barriers is that it don't stop RADON gas, and all other RADON grade barriers are only for under the slab. Thank you for the great video!

[@AmericanRadonMitigation]

Boy I’m not sure about that as it’s out of my wheelhouse. You’re welcome!

[@Josh-ux6zz]

RadonSeal. It’s a spray on sealant that soaks into the concrete.

[@Medic7000]

Have you tried or what are thoughts on flipping radon fan upside down and smoking it to see where leaking is coming from? I have a finished basement with carpet, and thought about doing this so I would only pull the areas that are leaking smoke to seal it. This would prevent me from removing whole carpet and finding areas that might have missed. Thoughts?

[@AmericanRadonMitigation]

Colin, with Radon West, near Calgary, Canada, has done this. He said it's an easy way to show homeowners why they may want to allow him to open up walls to seal openings to the soil.

[@bobtreiber8556]

I see you use foam sealer. I see some contractors use silicon. What's best to use for sealing basement cement cracks?

[@AmericanRadonMitigation]

We like using Radon Sealant when we have access to cracks. We use foam for the hard-to-reach areas and block tops. There are links in the description if you'd like to check them out.

[@bobbycrosby9765]

I have a 50 year old slab-on-grade foundation house with a borderline radon issue (level around 2). Any opinions on if simply sealing can get it to slightly more acceptable levels, or will a full mitigation system be required? I'd rather not lose any conditioned air, it can reach 105 here.

[@AmericanRadonMitigation]

Since you should seal if you install a mitigation system, you could certainly start with sealing and then monitor your radon. However, an EPA study found that sealing alone is not a good mitigation strategy.

[@mywalkies1949]

Can the floor still be sealed if it has been ceramic tiled by the previous owner? We did a test in our house and found the levels quite high. unable to see any cracks as the floor has been tiled

[@AmericanRadonMitigation]

I think the thin set under the tile would do an excellent job sealing cracks in the concrete beneath it.

[@chhopraki]

Here is the problem! If I spray foam that, then I won't have the gaps necessary to push the carpets through. What do you recommend?

[@AmericanRadonMitigation]

Are you referring to the gap below the baseboard?

[@BrentLagerman]

do you have an example of work on a really old house with a basement? Also do you work in the hudson valley ever :D?

[@AmericanRadonMitigation]

I don't think I have any videos of really old houses. The oldest one that I have worked on is from the 1860's. That's probably considered modern compared to some of the houses on the east coast, though. Haha, we serve Minnesota and western Wisconsin.

[@BrentLagerman]

@@AmericanRadonMitigation mine is 1870s, it has a new slab in 3/4 of the basement, other quarter is a crawlspace that we're digging out. Not sure how to tie the two together, but getting some ideas from your stitching videos...

[@BrentLagerman]

@@AmericanRadonMitigation do you happen to know of a good resource to find a good mitigator in the NY Hudson Valley area?

[@KRTube75]

Can a basement floor be sealed too tight for the radon mitigation fan to work effectively? I ask because when I built my house, we installed perforated pipe and 4" of gravel then 6mil plastic under the concrete slab. We installed a 4" pipe for future active radon mitigation if needed. Walls are poured concrete, 10' tall. Soil is dense southeastern red clay. I then sealed all around the perimeter as well as all cracks and expansion joints. This was back in 2008 and the basement is 3300 sq ft with 10' high walls. I never tested for radon because we're in a low risk area. I recently tested and we average 18 pCi/L in the basement so I decided to mitigate. We have 2 drains in window wells and 1 in a stairwell connected to the interior sump pits so I plugged those with Oatey drain seals and also capped the vents for the sump pits so the sump pits are now tightly sealed. I did some testing using a shop vac and pressure field extension testing showed about the same numbers everywhere but vacuum pressures were a bit high. To me, this indicates that things may be too tightly sealed so there's not enough air being pulled under the basement floor to remove enough radon. After installing a Festa AMG Legend fan, we're seeing about -1.75 W.C. of pressure as verified with a digital manometer. Seeing about -1.5 W.C. in test holes throughout the basement test holes. This comes to maybe 130 CFM. Radon levels have dropped to just about 4 pCi/L after 24 hours but I was circulating fresh air through the basement using a 20" fan for 3+ days prior to that and levels were about 0.4 pCi/L so they may not have fully stabilized yet. Would it make sense to bore several small holes in the slab at the opposite end of the basement and connect them using pipe to central manifold that pulls fresh air in from outside under the slab and out through the fan port? The basement is still unfinished so I figure I could do this relatively easily and use a valve to be able to adjust vacuum pressure/CFM to a more desirable level. Or would it make more sense to upgrade the fan to something like the AMG Legend Extreme?

[@AmericanRadonMitigation]

It sounds to me like your radon fan is way oversized. You only need a few pascals of negative pressure under the slab to stop radon entry. If it's as tight as you say it is, you should be able to use the smallest radon fan (Spirit, RP140, Rn1 or the Rn2 EC). You are trying to create suction under the slab, not airflow. If you have complete control of the slab and radon is still elevated, look at adjacent slabs (attached garage or front step) as a possible source.

[@KRTube75]

@@AmericanRadonMitigation Thanks! This definitely has me stumped. Levels in the central area stabilized at around 6.5 pCi/L. I'm working on checking levels near the door to the outdoor stairwell, window wells, garage slab, front porch slab and lower patio slabs now. There are no cracks or penetrations in those other slab areas so only permeation through the elastomeric waterproofing coating and concrete would allow entry. I'm going to keep at this until I have it figured out.

[@AmericanRadonMitigation]

Check out this video or others about tracking down radon entry points. kzbin.info/www/bejne/jJzYhotmltmCqa8si=mwWeQUZgP03Kep85

[@KRTube75]

@@AmericanRadonMitigation Thanks. I'll check it out. I've done more extensive testing and have eliminated the patio, porch and garage slabs as possible sources. The entire envelope of the house is spray foamed and all joints were air sealed during construction. I decided to pull negative pressure on the house yesterday while it was in the low 40s and monitored temps using an Infrared thermal imaging camera. There were no points of lower temperature air entry underground showing on the camera other than at the door and window seals. I tested the door and window wells and they have low radon levels. So this rules out any type of infiltration through cracks and gaps. As I mentioned, the walls have a thick elastomeric coating on the outside. The walls also have a drainage mat that's 8' high with a thick plastic backing that's fastened to the exterior to divert water to the footing drains. This really makes it near impossible for radon to be able to get in through the walls in a large enough amount to cause the readings I'm seeing. As a test, I put some weatherstripping on the lip of a storage bin that I brought outside to trap fresh, low radon air in it then put the radon detector in the bin and held it against the wall with a weight. After 1.5 hours, radon levels were at 14.3 pCi/L. I then did the same test on the slab and after 1 hour, levels have dropped and are at 5.3 pCi/L with a downward trend. The concrete for the walls came from a different supplier than the slabs. I'm suspecting that some material used in the concrete for the walls has a high level of uranium and radium. There's 91 cubic yards of concrete in the basement walls. 2775 sq ft of exposed wall and no air circulation in the basement. I really need a geiger counter that can do alpha particles to perform a good test to verify. For now, I'm going to take the concrete that was bored in the slab and test it in the sealed bin with the radon detector. I'll have to bore a chunk from a wall to test it as well. It's starting to look like I need to install an ERV to bring in fresh air. My other ERV only does 200 CFM and it's taking care of 4,700 sq ft of house already. The other option is to try to seal the concrete from the inside but that's a significant amount of work. An ERV would by much easier to install and would cost about the same as the sealer.

[@KRTube75]

@@AmericanRadonMitigation Testing shows that the concrete in the walls is actually the source of the radon I'm seeing even after sub slab depressurization. I also came across Bill Brodhead's research on very elevated levels of radon in condos where the walls and floors were all concrete and the concrete was the source the the high radon levels. I actually bored a chuck of concrete from the wall, placed it in a metal container with an Ecosense EcoQube and radon levels shot up to over 15 pCi/L and remained around that level. My next step is to determine the best way to mitigate. Either with a concrete sealer, ERV or both. Thanks for all the informative videos. I've watched most of them and they have all helped greatly with my adventures in mitigating the radon in my basement!

[@Tenpennycustoms4958]

I have a finished basement and the 2x2 wall framing sit on top of the slab where it meets the foundation. I have no way to get foam to seal that small gap… 😭

[@AmericanRadonMitigation]

Logan, try using the Great Stuff Pro gun with the small tips to inject foam behind the 2x2 if you have access. You could also seal the bottom plate to the floor and wall.

[@Tenpennycustoms4958]

@@AmericanRadonMitigation I had a small gap under the 2x2. I fired up the fan and I can hear air. I got a smoke pen so I hope it’s just this one corner. Thank you 👍

[@TrevorFisher]

Seeing that conditioned air is being pulled down like that makes me think that a plastic layer wasn't installed below the slab, is that correct? Or will conditioned air be pulled down below the slab even with a plastic layer between the gravel and slab?

[@AmericanRadonMitigation]

Good question, Trevor. Since the poly isn't sealed to the foundation, conditioned air is drawn below the slab through floor-to-wall joints.

[@TrevorFisher]

@@AmericanRadonMitigation ok I think I understand, so that would happen typically only at exterior walls where it pulls around the edge of the poly?

[@AmericanRadonMitigation]

It can happen anywhere there is a hole in the vapor barrier, for example, at a floor-to-wall joint or a plumbing penetration.

[@ryszka1]

What about finished basements?

[@AmericanRadonMitigation]

Most homeowners with finished basements only allow us to seal what's easily accessible, as you saw in this video. However, a few have allowed us to remove the baseboard and cut drywall to seal what's behind the wall.

[@kpsher367]

I am facing this radon issue currently in the house that I am trying to buy. It is currently has radon reading of 10.5 Pcil

[@AmericanRadonMitigation]

Are you in the Twin Cities area?

[@kpsher367]

@@AmericanRadonMitigation Hey - no I am on the east coast.

[@AmericanRadonMitigation]

We recommend you stay involved in the process of choosing a contractor rather than have the seller take care of it.

[@kpsher367]

@@AmericanRadonMitigation Interesting you said that cause I was thinking exactly what you said however I have been told to just ask that radon mitigation system be installed by a certified specialist .

[@AmericanRadonMitigation]

Good thinking. Not all contractors offer the same service, quality, or radon reduction. You'll want to look for a contractor that does pressure field extension testing. They will know what that is. It's our experience that many sellers are looking for the cheapest option, not necessarily the best option, which does make sense since they are moving and we are the most expensive option. Many of our customers negotiate during the sale process to get a price reduction and install the mitigation system after they close. You could use these questions to help select a contractor. americanradonmitigation.com/faqs/

[@TeslaBoy123]

If radon don't kill owner obviously utilities companies well be killer with super high utilities bills and 🤑 BTW never ever install drywall touching concrete floor bcz create a bad combination drywall and humidity water on concrete are not friend 😳