Radon, a real challenge where Im planning to build.

Hi to all,

My present property, a lot in a small town/city may be worthy of a small home and its has some great features, orientation is perfect, taxes low, a community supportive of small business and a farmers market right around the corner, its a superb fishing spot in a clean river.  Moderate (for our present day and age) climate, reasonable rainfall and sunlight.  Decent agricultural potential.  On my property there are nice mature trees blocking the Western sun and a wide open SSE aspect for Winter solar gain, and despite that its in a small city, it is located in a little out of the way corner of town with trees on at least three sides, probably the least traversed street in town.  HOWEVER, its a high radon area and area homes I know for a fact have had to have radon remediation of various kinds done to their basements to vent that radioactive gas. I have the option of building from scratch and I am wondering if there is a way selling the local engineer on some sort of green design that is ultra radon proof.  My first thought was that a traditional log cabin raised up on stone pylons would not contact the ground, hence radon gas would not enter the house.  If I wanted some sort of Earthship, Im sure its ultra insulated and ground hugging design would be great at trapping radon so that idea is out. Any ideas, creative thoughts on how to design a radon proof habitat?  PS I also worry about greenhouses and cold frames, would they have to be off the ground as well? Wouldnt a greenhouse be a perfect collector for radon gas? Any thoughts most appreciated.  Best..M

Ughhh, Radon!  What a bit of disappointing news.

I can only think of about 2 options and neither is great.

Option one is a traditional Radon abatement technique, but this requires extra energy and cycles lots of outside air—the opposite of good insulation.

Option two is to somehow completely insulate your basement from any gas intrusion, but I don’t even know if this is even possible.

At the very least, Radon should not be a problem above basement levels.  But I don’t know how comforting that information is.

I wish I had better news for you, but maybe you can adopt your plans so that you can avoid Radon altogether.  Come to think of it, I don’t think Radon will come from soil but from underlying rock that has trace levels of Uranium in it.  Would it be possible to mound earth (Not gravel or rock) around your structure?  I had an eccentric contractor relative who built a house with a basement, but he didn’t excavate.  He simply built the basement and house up from the ground and afterwards he brought in a LOT of fill to mound around his basement. The end result was a house that looked like it was built on a little hill.  As a side benefit, his basement had absolutely no problems with water seeping in.

I don’t know if this helps but this is about the best idea I can think up.

Eric

Thanks for that..Im not building any sort of basement at all. Im planning to be OFF the ground entirely so that air can vent below and around my house. Unless theres another way to do it.

Seems like in our travels maybe in Louisiana, I have seen homes with a crawl space under the house that was slightly raised and screened in to prevent flood waters from getting into the house.  Maybe 3' or 4' off the ground.

I am not talking about the houses in Florida that are built on stilts.

Maybe either of those might be an option though.

Since radon sinks to the very lowest level, I would think that any home built above grade and especially with a crawl space, Radon would simply not build up and become a problem.  Definitely check me on that though.

Eric

Radon will only collect in enclosed low spaces like basements, as it is coming up out of the ground, and it is heavier than air. If there is a radon problem in your area, then radon is leaking out of the ground all around you. In fact, we are all exposed to a certain quantity of background radiation, although it is generally so little that we mostly just ignore it. The issue really only becomes a problem when the concentration of the gas can build up, and you then subsequently breathe it in. It only emits alpha particles, which can be stopped by a sheet of paper, but once inside your lungs, it causes problems. I guess its the leading cause of lung cancer among non-smokers.

Anyway, if your house is not below ground, there will be nowhere for it to accumulate, and you will be fine. Also, the remediation methods usually just involve a small fan that blows air from below your basement slab (you cut a hole and dig like a little sump) and up to the roof. It will probably use less than 20 watts of power, so I would not worry too much about the environmental impact of that.

I appreciate all that feedback and it jives with what I have learned on the subject, so my tentative building plan includes a building raised at least a couple feet off the ground to allow prevailing winds to disperse any radon gas, and yes thanks to start with an elevated site and not create any potential radon traps in my building plan. Greenhouses proper could be off the ground as well with flooring and airflow below, But as to coldframes I wonder a bit if that isnt a design to trap radon so that my overwintered crops are getting the benefit of trapped radon gas? But if it were a large enough system I could vent gas with fans also?

I dont think you need to worry about radon accumulating in greenhouses or cold frames. The amount of gas coming out of the ground is very low, and it would only accumulate if there was basically no air leakage out of the structure. Most greenhouses will have some sort of roof vent so it doesnt overheat, which would I think be more than enough airflow. I am not sure exactly what you are describing when you say "cold-frame", but if it is too small to walk inside it, then you wont really be breathing anything that accumulates inside anyway.

Radon is a consideration where I live as well. Like Carl said, all you need is a bit of ventilation to keep it from building up. The retrofits to the basements of old houses aren't terribly expensive or hard to do, so I'm sure whatever design you come up with will be compatible.

Thanks for that Carl, I guess I can monitor everything with a radon detection kit, but even if Im too big to fit in the vegitable's cold frame, aren't the vegitables being irradiated?  M

Yes, your vegetables would be getting a small dose of radiation. However, everything experiences background radiation, and only if the air in the cold frame was very still would radon have a chance to build up. Unlike a basement, the coldframe is going to get hot in the sun - hot air rises, and it will have to suck air in somewhere to replace the hot air that is escaping.

The second part of this is that not all radiation is created equal. There are 3 principle types when talking about radioactive decay, Alpha, Beta and Gamma radiation. Radon has a long convoluted "decay chain" that leads it to eventually turning into a stable form of Lead. Every step along the way emits only alpha or beta particles. Alpha particles are essentially helium nuclei stripped of their electrons and ejected from the nucleus of an atom during radioactive decay. It has a lot of mass, but in the subatomic world, it is a huge particle, so it does not really penetrate solid objects. Basically, you can stop this type of radiation with a sheet of paper. The outer layers of your skin is ample protection, and as such it is really only dangerous if it gets inside your body. If it gets in your lungs, where the tissues are very thin, it can cause damage to your cells. Beta particles are just high velocity ejected electrons. They penetrate deeper, but since they are so light, they do not do much damage. They can cause skin burns, but you would have to be exposed to a LOT of beta particles. Again, if they get inside your body, its bad news.

The type of radiation that you really want to watch out for is Gamma rays. Like high powered versions of x-rays, they will mess up your cells good. If you are lucky, you will develop immense strength, and take on a greenish color, but most people just get cancer and die from it :) Thankfully, nothing that radon decomposes into gives off gamma rays.

Again, all of this requires there to be an elevated concentration of these radionucleotides, and that you breathe them in, and that you do it for prolonged periods of time. Radiation is all around us. While no amount is good for us, life on earth has done a pretty good job of adapting to it being there.

Thank you for that Carl and the science behind it. So for purposes of building a greenhouse  it seems you're saying that think a slightly leaky system would help move any possible radon gas out and laying down a barrier would be of additional help.

I build mountain houses, most of the time we build on recycled power poles from the local electric co-op. We get them free and just notch that outside band of the house directly into the post. I've built houses from 3' to 16' off the ground. The higher you go the more cross bracing you will need. Some of the houses were simple insulated underneath and sheathed in 1/4" plywood to keep the rodents out. Others we underpinned.

I think as long as you are off the ground and have foundation vents, you will be good for radon.