Radon help!

[ArthurL1]

Originally Posted by carcrazy67

I am quite familiar with the process of radon remediation and agree with "most" of what you are saying. However, it is indeed possible to remediate radon without sealing the crawlspace. Not common, and I wouldn't recommend it, but possible as I have seen it done successfully many times.

I'd be interested to hear how it was done in the cases you saw. In order to vent the gas in a crawlspace (properly I mean and according to code and certification standards), the vapor barrier would need to be airtight, wrapped at least partially up the foundation wall and piers, which minimally results in at least a "partially sealed" crawlspace. I realize the definition of "sealed crawl" and how thorough that is probably varies - radon mitigation code descriptions that I've seen do not require a weather tight crawlspace door, or even sealed vents, and certainly not dehumidification measures.

In fact, a crawlspace with a radon mitigation system that simply left their vents open (the opposite of sealing) would actually be more effective against radon, because the gas has one more way to escape before seeping into the home. I believe this is uncommon, however. Most people who already leave their vents open have not yet needed to deal with high radon measurements, because most of the gas will find its way outside through the vents.

So, I'm also curious what you mean by seeing unsealed radon mitigation done successfully in a crawl? If success is defined as a radon reading under 4.0 pcl, it could be that some other factor was contributing to keeping the radon levels low. Would a fan with negative pressure that is simply venting the crawlspace air (with no attention to sealing the vapor barrier) reduce radon levels? It might reduce them, but would be massively inefficient compared to mitigation done properly. And if the measure of success is what the radon reading is at the time the contractor deems the project done, it's not an adequate measure because readings can vary tremendously throughout different times of year (monitoring must be ongoing).

Understand I'm not doubting what you've seen here, just curious what exactly it was and how it was deemed successful. Radon mitigation is still unregulated in NC, so I'm sure there are still plenty of code violations happening in this industry.

Originally Posted by carcrazy67

The cost of installing a vapor barrier around here typically runs $500-$800 depending on the size of the footprint. The vast majority of houses in our area already have a vapor barrier as it has been required by code for many, many years with an exception for well-drained soil (which for the most part we do not have).

If their vapor barrier is simply applied to the ground without sealing around walls and piers, it won't be very useful against radon. What would be worse is if they have a vapor barrier that's simply laying on the ground, and then close their vents or take other sealing measures without testing for radon regularly. I may be wrong, but I believe the "typical" builder procedure, unless the homeowner specifies otherwise, is to simply throw down a minimal thickness vapor barrier (6mil) and call it a day, which does reduce the amount of moisture (not as well as a sealed vapor barrier, but better than nothing).

But then it is left up to the homeowner to decide the rest (open or close the vents, etc). Because of the humidity around here, I think the trend is to close the vents and dehumidify or condition, which can be dangerous without radon consideration.

[ArthurL1]

Originally Posted by coldriver10

All of the posts here were very helpful, but this one was key. I got a 2nd quote which was about $2100, but they use a 6 mil barrier whereas the more expensive company uses 15 mil. Longer warranty, too. I opted to go with the pricier, but hopefully more effective and longer-lasting, option.

Thanks again!

You did the right thing IMO, you'll get way more mileage out of the better vapor barrier.

[sacredgrooves]

$2100 vs $3300.....the price difference between 6 mil and 12 mil vapor barrier is maybe $100 total. If no other difference in their service, not even remotely worth the price increase. Frankly, you have to try to tear 6 mil as it is, 12 mil would be more than good enough and 15 is overkill, especially for walls and piers. My company has installed hundreds of sealed crawlspaces and I have bought enough vapor barrier to cover a small town over the years, so figured I would pass that on.

[carcrazy67]

How does radon come into the crawlspace??? It is because most crawlspaces, for whatever reason (and there are several), "suck!" The key is to develop a crawlspace that doesn't "suck." There are several ways to go about this, however in some circumstances it can be as simple as making certain that the air return ductwork is properly sealed and any penetrations between the crawlspace and house such as plumbing penetrations, construction joints, etc are sealed. In the cases I've seen, just the installation of a fan (and open vents) made a reduction in the radon levels as it eliminated the negative pressure. Did it reduce it to the free air level of around .4 picocuries, no but it did reduce the levels below the EPA action level of 4.0 picocuries when they were previously above it.

Obviously a sealed crawlspace with a remediation system is a far superior method and if someone can afford it, it is without question, the way to go. If they can't, there are some other ways to go that "may" achieve adequate results for very little cost.

Yes, most builders use 6 mil vapor barrier. Does it work? Yes, but not as sturdy as 10 mils or greater.

[ArthurL1]

Originally Posted by sacredgrooves

$2100 vs $3300.....the price difference between 6 mil and 12 mil vapor barrier is maybe $100 total. If no other difference in their service, not even remotely worth the price increase. Frankly, you have to try to tear 6 mil as it is, 12 mil would be more than good enough and 15 is overkill, especially for walls and piers. My company has installed hundreds of sealed crawlspaces and I have bought enough vapor barrier to cover a small town over the years, so figured I would pass that on.

I wouldn't go with the higher quote solely because of the cost of the barrier, I would go with them because the use of the thicker barrier is an indication they know what they are doing and are focused on quality, while the company trying to use the 6mil has taken a minimalistic approach and is trying to do the least amount of work at the lowest cost possible.

6mil vapor barriers are designed to be replaced after 10 years or so, and are unacceptable for radon work, because every time someone goes under the home and into the crawl for plumbing, wiring, or other type of work, their boots will inevitably tear small holes in the 6mil, allowing more and more gas to bypass the vent system and seep into the home.

The better vapor barriers that are suitable for radon mitigation are 12mil or higher, reinforced with nylon mesh, and are difficult to tear holes in in even if you're trying to.

From the installer's perspective, the big difference between the two is that 12mil+ is much harder to work with because of the additional weight of the roll. Pick up a roll of each, of equal length, and walk around with it and you'll see what I mean. The time, labor, backaches/headaches ends up being much more than double, but the end result is worth much more than the difference in cost of materials. What you're paying for here is additional labor involved and the peace of mind of a quality installation done right the first time.

Never accept a 6mil vapor barrier installation if the goal is to keep radon down. The radon won't penetrate it while it is new, but after it has seen a few years of foot traffic, on and had a few micro-tears, it becomes much less effective. Chasing down needle sized holes in a vapor barrier on an ongoing basis is about as much fun as looking for needles in a haystack, most people who have dealt with that end up just paying someone else to do it right with better materials.

Trust me, OP, you're doing the right thing by going with the higher quote. One of those companies demonstrates competency and commitment to quality, and the other does not when it comes to radon abatement.

Given that the difference in cost of materials is so low, there are only two good reasons I can think of that an installer would opt for the cheaper material: they are too lazy to deal with the larger heavier roll, and they want their client to call them back in a few years for repeat business so they can do it again.

[sacredgrooves]

Originally Posted by ArthurL1

I wouldn't go with the higher quote solely because of the cost of the barrier, I would go with them because the use of the thicker barrier is an indication they know what they are doing and are focused on quality, while the company trying to use the 6mil has taken a minimalistic approach and is trying to do the least amount of work at the lowest cost possible.

6mil vapor barriers are designed to be replaced after 10 years or so, and are unacceptable for radon work, because every time someone goes under the home and into the crawl for plumbing, wiring, or other type of work, their boots will inevitably tear small holes in the 6mil, allowing more and more gas to bypass the vent system and seep into the home.

The better vapor barriers that are suitable for radon mitigation are 12mil or higher, reinforced with nylon mesh, and are difficult to tear holes in in even if you're trying to.

From the installer's perspective, the big difference between the two is that 12mil+ is much harder to work with because of the additional weight of the roll. Pick up a roll of each, of equal length, and walk around with it and you'll see what I mean. The time, labor, backaches/headaches ends up being much more than double, but the end result is worth much more than the difference in cost of materials. What you're paying for here is additional labor involved and the peace of mind of a quality installation done right the first time.

Never accept a 6mil vapor barrier installation if the goal is to keep radon down. The radon won't penetrate it while it is new, but after it has seen a few years of foot traffic, on and had a few micro-tears, it becomes much less effective. Chasing down needle sized holes in a vapor barrier on an ongoing basis is about as much fun as looking for needles in a haystack, most people who have dealt with that end up just paying someone else to do it right with better materials.

Trust me, OP, you're doing the right thing by going with the higher quote. One of those companies demonstrates competency and commitment to quality, and the other does not when it comes to radon abatement.

Given that the difference in cost of materials is so low, there are only two good reasons I can think of that an installer would opt for the cheaper material: they are too lazy to deal with the larger heavier roll, and they want their client to call them back in a few years for repeat business so they can do it again.

I am not arguing that 12 mil isn't a better product, especially for radon sealing, just that the price difference in the quotes is extreme. Reinforced 12 mil is actually easier to work with imo, it lays down much nicer than 6 mil. The extra weight isn't a big deal, the sections installed are cut outside and then brought into the crawlspace.

Here is a rundown of the materials needed and approximate cost as an fyi:

4" PVC exterior drain pipe with collection holes $1/linear ft, maybe 100' needed
I pay $175 for a 1,000 sq ft roll of reinforced 12 mil (6 mil would be $50, 10 mil would be $80)
Moisture resistant seam tape would be around $75
Radon fan to pull a vacuum $200
Electrician to wire the outlet $200
Two workers for one full day. In this industry, they make approximately $15/hr.

You are looking at ~$1,000 to do the job from a business standpoint. $2100 is reasonable, $3300 is excessive. Radon mitigation is usually $1500-2000.

[ArthurL1]

Originally Posted by sacredgrooves

I am not arguing that 12 mil isn't a better product, especially for radon sealing, just that the price difference in the quotes is extreme. Reinforced 12 mil is actually easier to work with imo, it lays down much nicer than 6 mil. The extra weight isn't a big deal, the sections installed are cut outside and then brought into the crawlspace.

Here is a rundown of the materials needed and approximate cost as an fyi:

4" PVC exterior drain pipe with collection holes $1/linear ft, maybe 100' needed
I pay $175 for a 1,000 sq ft roll of reinforced 12 mil (6 mil would be $50, 10 mil would be $80)
Moisture resistant seam tape would be around $75
Radon fan to pull a vacuum $200
Electrician to wire the outlet $200
Two workers for one full day. In this industry, they make approximately $15/hr.

You are looking at ~$1,000 to do the job from a business standpoint. $2100 is reasonable, $3300 is excessive. Radon mitigation is usually $1500-2000.

A well-done radon solution would be priced based on the size of the crawl, number of piers that need to be wrapped, etc. What if it's a 3300+ sq ft ranch (and thus potentially a crawl of same size)? What if the homeowner wants the pipe run through the attic or some other special consideration? Tape is used around the piers, but the barrier should be secured to the wall with wood strips / screwed into the concrete and spray-foamed to be air tight. I didn't even see priced in list of materials the connected duct work throughout the entire space of the crawl (which is really what makes it all work effectively). Without the ducts or some sort of collection chamber system, the vacuum pressure would do little more than pull the barrier tight to the ground and some of the gas would never make it toward the fan in a decent sized crawl.

I'm just saying there are a number of variables to consider before a cost can be deemed reasonable or excessive, everything from the size of the crawl, to the type of materials used, to the thoroughness standard of the contractor and/or homeowner, to special considerations to where the home is located.

I would agree that $3300 seems a bit higher than what I would have guessed, but I am not making assumptions about the size of the home or the other factors. Personally, I would not have gone with the company that suggested the 6mil vapor barrier for radon treatment on principle alone -- they've already lost my confidence with that one.

You said $2100 is reasonable and $3300 is excessive, but keep in mind the "reasonable" quote was made unreasonable by the fact that they suggested using a material that was adequate for moisture control but inadequate for radon control, all so they could put an extra hundred or two in their pocket. To me that disqualified them as a reasonable option (then again it's not my house in question so all of this falls back to the judgement of the OP). Sounds to me he discovered a get-what-you-pay-for situation in this case.

[sacredgrooves]

Originally Posted by ArthurL1

A well-done radon solution would be priced based on the size of the crawl, number of piers that need to be wrapped, etc. What if it's a 3300+ sq ft ranch (and thus potentially a crawl of same size)?

I can tell by the quoted prices that the crawlspace is not sized out of the ordinary. Just fyi, I am not at all trying to argue with you as you are well informed and have definitely looked into the issue, just passing my experience along. I am very well versed in this though having inspected over 10,000 crawlspaces, sealed around 750 of them, and tested radon or re-tested after remediation approximately 8,000 times. I can almost stand outside of a crawlspace and use telepathy to determine what it needs by now lol.

What if the homeowner wants the pipe run through the attic or some other special consideration? Tape is used around the piers, but the barrier should be secured to the wall with wood strips / screwed into the concrete and spray-foamed to be air tight. I didn't even see priced in list of materials the connected duct work throughout the entire space of the crawl (which is really what makes it all work effectively). Without the ducts or some sort of collection chamber system, the vacuum pressure would do little more than pull the barrier tight to the ground and some of the gas would never make it toward the fan in a decent sized crawl.

4" Schedule 40 PVC with collection holes under the barrier and tied to the fan on an exterior wall is how it is done in crawlspaces. The PVC was listed on the pricing I provided. Vapor barrier is typically secured with continuous adhesive backing strips that seal as well as fasteners through the block/sealant strip. Mastic is also commonly used as a sealant. I rarely see furring strips, but they work fine too as long as it sealed as well.

I'm just saying there are a number of variables to consider before a cost can be deemed reasonable or excessive, everything from the size of the crawl, to the type of materials used, to the thoroughness standard of the contractor and/or homeowner, to special considerations to where the home is located.

I would agree that $3300 seems a bit higher than what I would have guessed, but I am not making assumptions about the size of the home or the other factors. Personally, I would not have gone with the company that suggested the 6mil vapor barrier for radon treatment on principle alone -- they've already lost my confidence with that one.

You said $2100 is reasonable and $3300 is excessive, but keep in mind the "reasonable" quote was made unreasonable by the fact that they suggested using a material that was adequate for moisture control but inadequate for radon control, all so they could put an extra hundred or two in their pocket. To me that disqualified them as a reasonable option (then again it's not my house in question so all of this falls back to the judgement of the OP). Sounds to me he discovered a get-what-you-pay-for situation in this case.

6 mil is allowed for radon mitigation and not "that" inferior. It really is difficult to tear and the fan creates a vacuum anyway so all that really happens is crawlspace air gets pulled under the vapor barrier at any potential tears, and fed into the collection pipes instead of the other way around (which would be more of a concern). I did add the caveat that if all else is equal, the price is excessive. Since I hear all about remediation and its costs at least once a week, $3300 sticks out as a red flag. Radon mitigation and crawlspace sealing is rampant with rip off artists, and I don't like to see my fellow CD'ers pay more than necessary.

[ArthurL1]

Sacredgrooves : Similar to what you said, I also do not want to get into an endlessly complex debate, so this will likely be my last post on this particular aspect of the thread. Yes $3,300 struck me as a little on the high side as well, and yes I agree that it is common sense to want to pay the lowest price possible with the caveat you added, of all things being equal. However I do need to point out that all things are not equal in the quotes the OP received. 6mil is "allowed", but because radon mitigation is unregulated in NC, many things are currently allowed that are a bad idea. Adhesive fastening is probably the only reasonable option with such flimsy material as 6mil. Furring strips and fasteners would probably only contribute to the vapor barrier becoming torn more easily with 6mil. Drilling a fastener into the wall with the membrane behind the strips becomes a better idea when applied to thicker material that is reinforced by mesh (which if course won't tear). Adhesives tend to fail over time. Applying tape to dirty concrete can last a long time, but not as long as metal fasteners drilled into the concrete. So while I'm sure many installers don't bother or will say "its overkill", furring strips + fasteners + sealing foam + stronger vapor barrier amount to a more durable installation than a thinner vapor barrier with tape and adhesive backing. Maybe it is overkill if the homeowner is not planning to remain in the home long to do the more durable and effective installation, but my point was simply that the more durable installation does require more labor and materials, and therefore would tend to be subject to higher quoted prices. I have not seen the two quotes the OP received, so I won't make assumptions about what exactly the $3,300 is buying him, or attempt to assume to estimate the size of his crawlspace based on the quote (still a bit perplexed by your comment there -- unless maybe you've interacted with the OP privately, the prices he was quoted and posted here would not give you enough info to accurately determine the size of his home, there are just too many variables involved).

To the OP: My best advice to you or anyone else is simply to make sure that when it comes to radon mitigation that you hire a certified mitigation company, and that advice is reflected here: The North Carolina Radon Program North Carolina Radiation Protection Section NC Division of Health Service Regulation NC Department of Health and Human Services

Some crawlspace treatment techniques that are more effective for moisture control and may not be the same techniques that are more effective for radon treatment. In a home that has tested high for radon, personally I would place my priorities on treating that first.

[coldriver10]

Interesting discussion! Thanks, guys. I agree that $3300 felt pretty high, but this was the estimate based on the downstairs square footage (it's a decent sized house). The crawlspace is not quite that large, so I'm hoping it'll be a little less expensive than that. This is a certified company in the area that has excellent reviews and literally only does radon remediation...nothing else. I obviously have no knowledge on the subject, but I think it's more likely a situation where we're paying for good quality (maybe excessive or unnecessary quality, that remains to be seen, but at least good) rather than we're being taken advantage of. They'll measure everything tomorrow, so I can update you with a price :P