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Discussion Starter · #1 ·
I have installed 4" PVC straight through after the connection in my basement. I used 4" PVC to hopefully avoid having to use any type of fan. (Passive venting) I am looking for something to cap the top of the pipe but read not to use anything in climates that have cool winters...Zone 5 here. Is there a good product to use? I fear leaving the 4" pipe exposed will allow varmits to get in and fall down and die...but also allow rainwater to easily enter to the soil below my basement concrete. It's not a sump pump, so there is no way for the excess moisture to escape besides evaporation. (walkout basement with sloped lot, so sump pump was not needed).
 

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Discussion Starter · #5 ·
Would it be safe to assume the moisture that does drop down can soak into the soil, no problem? There's not really a way for it to dry either besides the vent or through permeation with soil. I guess I should buy at least the screen and try it. Better than a squirrel or bird nesting or falling and clogging the vent's ability to, well, VENT.
 

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@alpha, "I used 4" PVC to hopefully avoid having to use any type of fan."

A passive radon installation will do little to reduce your radon levels. They are installed to be in place in case a fan system is needed. As for the 4" pvc vs a smaller pipe you are dealing with pressures and very little air flow. A larger pipe isn't going to move more air.

A typical radon system with a fan could create a pressure of 1 inch of water column, that’s 250 Pascals. A residential passive system will produce varying pressures ranging from slightly positive to maybe a negative 10 Pascals, weather dependent.

Have you tested for radon and what were your readings?


As for moisture entering from above, what did you install under the slab, gravel and a vapor layer?


Bud
 

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Discussion Starter · #7 ·
@Bud
I have not tested yet. This was my new house build so I implemented the system just to be safe. I also have read that if you have a straight pipe, largest diameter possible, towards the conditioned (warmer) walls then convection will cause enough ventilation without the use of a constantly running - energy using fan.

I have 4" of pea gravel and a 10mil poly barrier below my concrete. I can see how the moisture from rain is probably not a problem. It would be non-concern if I did have a fan causing negative pressure. I really hope to not need one. I do know that an animal may be on the roof or checking out the pipe cause problems with it. I'd buy that varmit guard but it seems overpriced online there and just because of the concern that the moist air freezes on the grill part and can cause blockage in the winter.
 

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@Bud
I have not tested yet. This was my new house build so I implemented the system just to be safe. I also have read that if you have a straight pipe, largest diameter possible, towards the conditioned (warmer) walls then convection will cause enough ventilation without the use of a constantly running - energy using fan.

I have 4" of pea gravel and a 10mil poly barrier below my concrete. I can see how the moisture from rain is probably not a problem. It would be non-concern if I did have a fan causing negative pressure. I really hope to not need one. I do know that an animal may be on the roof or checking out the pipe cause problems with it. I'd buy that varmit guard but it seems overpriced online there and just because of the concern that the moist air freezes on the grill part and can cause blockage in the winter.
I would think the warmer air would keep it from freezing over.
here is another vent cap prob the one i prefer.
http://www.amazon.com/RadonAway-Fan-Pipe-Cap-Screen/dp/B008D7OE72

as far as price goes it is comparable to what you will get at any local store minus shipping. unless of course you can get a contractor discount.;)
 

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Discussion Starter · #9 ·
@Mingledtrash

I liked that one better, too, because it made moisture a lot less likely to enter - but the second review on Amazon had the exact problem I am afraid of being in the same climate as he was. I'll ask the building inspector for suggestions, but around here radon mitigation is not well regulated or even educated to the builders very much.
 
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