By chance I saw that there are a lot of radon questions here and it got me thinking:
Do I need to concern myself with potential radon levels when planning to build a new house? My question is based on long-term health considerations, and not so much any legal requirements. I plan to live there the next many decades.
Construction-wise, I have these specs:
- For cost reasons, the house would be built without a basement (just a concrete-slab foundation) and without those cool newfangled active-ventilation systems.
- Local laws require the house to be certified airtight.
- There will be floor heating, so no radiators to create natural convection.
- There will be a gas furnace that is independent of room air, so no air exchange there either.
I've read that radon seeps through the house from below, and the house need to be ventilated in order to get rid of the radon. Does this apply only if you have a basement, or always to the lowest floor in a building, or to every room in the building? What is the principle here?
I don't know what the radon levels would be in my area (Vienna, Austria), nor how to find out about this.
Best Answer
You should consider, but not invest now. Wait and test, before treating. Small design changes now, can make implementing a fix later, easier.
Radon is everywhere, to some level. If you have higher levels of radon, then you need to be concerned with the rate that fresh air is exchanged in your home. Houses are much tighter today, so be more aware with a new house.
Many factors affect where radon collects. Do you heat with wood? That moves air around your woods stove. Do you have leaky windows? That exchanges small amounts of air all over the house.
To get a general sense, ask a few neighbors if they have tested for radon. On the other hand, I have rock under my house, while my neighbor has sand, so things can vary quickly. You could call a few local excavators, or well drillers, as they are likely to have a guess. Fill (the dirt and stone under your lawn) gets moved around so much, that you can't rely on historical or nearby testing.
Your local building inspector is probably going to be your best resource. And since you're going to be seeing that person alot anyway, you might as well make contact.
Let's say you have a concrete slab, with stone under it. Whether or not this is a basement doesn't matter. Your builder will put a layer of plastic under that, to keep out the "rising damp", and it may help limit radon. It would be a simple thing to ask for 8 feet or so, of perforated pipe, capped, to be placed under the slab. In the middle, have a 90 with a pipe come up through the concrete into your house. Cap it for now. $20. When you test later, it may be enough to stick a bath fan on it, and pipe the air outside. Cold ground air is simply piped outside, and radon may not collect.
If you are putting in ducts for heating/cooling, ask about how an HRV could be attached. I think this is the ventilation you were thinking of (heat recovery ventilator). The HRV is about $1k, and could be bought later. The ductwork is hard to do later.
In addition to air quality, you may also want to check on radon levels in your water, if you have a well.
Cost reduction is good. Basements are often incorrectly drained, so can be damp and harbor mold. On the other hand, if you put in good drainage, basements are cheap square footage. You might consider reducing closets and rooms and keeping the basement.