I work for a builder doing multiple acquisition-rehabs. I am looking for information on Radon Mitigation in a remodel situation. Our houses typically are +-100 years old and have basements of either CMU or bluestone. I have done basic passive systems in new construction so I know a bit: i.e. tying a 4″ PVC into the interior drain tile and running it out the roof.
What kind of systems are available for remodelling? I am assuming that they would also involve the pipe run through the roof–perhaps with a fantech inline fan. Seems like the big question I have is how you go about depressurizing underneath a slab, especially since most of our projects are on fairly wet clay. (in fact, most of these old basements have concrete poured straight onto clay). Do all the systems require digging in a perimeter draintile (most of our projects either have no drain tile or the tiles are not functioning)? Or is there a quicker, easier way?
Thanks.
Replies
Don't know to answer your question but I recently read that some granite and stone slabs used in kitchens are sources of radon. What on earth do you do then as well.
Just A Guy With A Hammer
Put it in your recipe.
I never thought, heck it might let the turkey sit out longer before spoiling on holiday.
Maybe even help in a short moment of sterilization by tea bagging the counter before sex. Cheaper than the pill. Just don't know how many times you could do it before the boys dry up.
Iam absolutely sorry but it's nicer than my first thought.
Just A Guy With A Hammer
Better get rid of your kid's rock collection, too!
Shouldn't be an issue, really. It's not like it will 'outgas' forever. I think the likelyhood of radon from the counter is very low ... buy the time it is quarried, cut, polished, shipped, fabricated for your kitchen and installed, it should be a non issue.
Radon is airborn. It has a very short half life (minutes if I recall). It's not like the counter is or can constantly generate radon.
While I will not say whether a granite counter top can possibly produce enough radon to be a significant hazard, it is not just a matter of releasing the radon that was trapped in the stone before it was mined. Radon itself breaks down rather quickly with a half life of about 3 days but radon is produced by the decay of radium which if it is in the stone will be their a long time. Radium has a half life of 1602 years. Thus, if you make a counter top out of a granite with a radon hazard and wait until the year 3611, it will only be omitting radon at half the rate that it is today.
Yes ... radon, though is an airborne substance and it moves through the air in the soil and then into the house. I'm thinking radon in counters is effectively a non issue. If you have radioactive counters, you have other problems, I'm sure.
But ... apparently there is some heated discussions surrounding radiation contaminated granite counters ... I Googled it. So what I say here is only my semi-educated opinion unsupported by any detailed research (which apparently may not really exist (in support or refuting any claims)).
Personally, I generally feel that we often expose ourselves to many other just as dangerous situations as radon. I lived in a house that had 4 times the 'acceptable' levels of radon. I've also been around situations of materials w/ asbestos.
IMO granite counters with high level of radon 'outgassing' is highly unlikely. Yeah, my cell phone can set off a gasoline fire at a gas station, but people use them all the time w/ little dire consequences. Ditto jump starting a battery improperly ... but it is done millions of times w/ no consequences.
End of my discussion. I've said to much already.
Yeah, we've got about double the limit of radon in our house too, but I'm not too worried. (Everyone else has two heads too, don't they?)
The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith
Only two for you??!! I've heard two heads are better than one.
The problem is I keep getting into arguments. I need a third head to mediate.
The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith
Actually, the counter CAN constantly generate radon, as elements in the stone decay. That's the problem. But the danger is largely theoretical, since the amount of radon generated would only be a problem if you built a tent around the countertop and slept in it.
The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith
Check to see if MN has a licensing requirement to do radon mitigation
"Ask not what the world needs. Ask what makes you come alive... then go do it. Because what the world needs is people who have come alive."
Howard Thurman
Install 6 4" black abs drain pipes on the south or west side of the house. The pipes will go from the eaves to various part of the underfloor area. When the sun hits the pipes, it will draw air because it is a thermo-siphon and will not have a electrical bill.
I would check out the ASTM Standard E2121-03 (Standard Practice for Installing Radon Mitigation Systems in Existing Low-Rise Res. Bldgs.), as well as the US EPA's Guidance document "Radon Reduction Techniques for Existing Detached Houses" (EPA/625/R-93/011). The EPA doc has a lot of great info for sub-slab depressurization systems, including some good diagrams.
I will see if I can find an electronic version of either tonight in my piles of files and hopefully post.
I don't do any radon mitigation systems, but work for an engineering firm here in NJ and NY that uses the same technology for mitigating contaminated groundwater (and associated vapors) under homes. These are all installed in existing homes with a minimum amount of disturbance to the basement and structure. In a nutshell, we find a central spot in the basement (eg - under stairs, closets, etc.) and drill out a 4" dia. hole. From there we route 4" sched. 40 PVC along the ceiling to some point on an exterior wall where the HO would not mind a typical radon fan to be mounted.
Hope this helps.
It looks like it is only available in print.http://www.epa.gov/radon/pubs/Maybe not.Found this.http://cfpub.epa.gov/si/si_public_record_Report.cfm?dirEntryID=124795But is not download right now.
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William the Geezer, the sequel to Billy the Kid - Shoe
Edited 1/15/2009 6:01 pm by BillHartmann
Thanks, it does. It is not a big issue with me, but some of the banks that fund us want to see radon mitigation in all newly remodelled houses. I am tasked with figuring out a reasonable budget. I must say I am a bit skeptical of the whole thing in my area. The publication in the link you posted talks about pumping out the cores of hollow core block, and that might have merit if it is possible. But so many of our old houses have basement floors poured straight on very heavy clay, and it's hard to imagine drilling a hole in the slab and applying negative pressure would have much of an effect.
But so many of our old houses have basement floors poured straight on very heavy clay, and it's hard to imagine drilling a hole in the slab and applying negative pressure would have much of an effect.
It wouldn't, because air will not pass through clay.
But, guess what? Neither will radon.
http://www.kgs.ku.edu/Publications/PIC/pic25.html
"In general, clay soils limit and sandy soils promote radon movement. However, clay soils are susceptible to seasonal moisture changes that cause cracking or swelling, which could open or close avenues of radon transport."
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Edited 1/15/2009 8:35 pm ET by Riversong