Cool!

For something that small, I would probably line the pit with mortar or concrete.

Ditto for the Lexan. Seal to floor with silicone, which can be removed easily.

Jim, thanks for your service. You are one of my favorite Trainers and a pleasant fellow to be around. Years ago, you helped me refine my "sales pitch" and risk communication, which has helped me succeed in business. You will be missed!

Agree with Dan. We tap walls, upper slabs 4-5 times/yr. Dick makes good points about negative effects. Big question is: Where are you "pushing" the radon to?? Did you do follow-up test UPSTAIRS?

i think I see the problem....the manometer tube is connected to the pipe on the discharge side of the fan, right?

There is no interpretation needed. Current SGM-SF 2017, Soil Gas Mitigation Standard for Existing Homes says exterior mounted vent pipes must extend at least 6" past the edge of the roof. The writers of earlier Standards always intended "eave" to mean the edge of the roof deck.

Mention it and let the Home Inspector be responsible for his own competency, or lack thereof.

As always with anything new/weird....DO DIAGNOSTICS before quoting mitigation. The only similar thing i have seen was a house with below-grade wooden exterior foundation walls. It had a traditional concrete slab over crushed stone.

You can not make the test tamper-proof.
If it is movable; someone can move it: if you immobilize it, it can be covered. Where there is a desire to tamper with a test, a way can be found. Covers can be unscrewed; holes can be sealed; bags can be taken down.

I agree with the point Bob made about defensibility.

FYI: according to manufacturer DuPont, "Tyvek® HomeWrap® stops air movement through the walls...", and "Tyvek® weather barriers can have a positive impact on energy efficiency by helping to control air and water intrusion in walls."
So, unless you can point to research that proves that a product designed to block air movement does not have any effect on radon movement, or can point to a recommendation from a test device manufacturer, I would be hesitant to use it.

One thing to be aware of: in my experience, most of the people I know who have Safety Sirens do not follow the manufacturer's recommendations for recalibration. If my memory is correct, that recommendation is to send the unit back for recalibration once per year, at a cost equal to about 60% of a new unit.

Thank you, Paul, for your service to the cause. Your passing leaves a large void.

Clearly, our Standards are not keeping pace with changing building methods. I personally think the Standards have become far too complex by trying to offer a multitude of micro solutions for every conceivable situation rather than fewer macro guidelines.

Bruce, the problem is that when the bottom of roof deck is insulated there are no gable or ridge vents, so the attic is now an unventilated space within the "envelope" of the house. These same issues apply to unventilated "attic spaces", which are really just closets, behind knee walls in bonus rooms above garages.

Sam, there is always the option of installing the fan above the roof.

I have heard of a project where the drilling was done with a post-hole drilling machine, with bits made of threaded pipe sections with 1/4" rebar tack welded around them in a spiral. Don't want to mention names on public forum without permission, but can email you.

Yes, Dick. We usually assemble and install the vent pipe, then take it down, paint it, and reinstall it. This can be problematic with a tall vent pipe. One can also wrap 1 1/2" masking tape around the pipe ends when painting them so there is unpainted pipe to cement into the couplings.

Is this a separate study from the one recently reported that showed an increased risk of blood cancers in women with increased radon exposure?

Stains are designed to soak into porous surfaces. Paints leave a film o the surface. Primers are designed specifically to bond and adhere as well as block stains/lettering, etc. Primer + topcoat is better than two coats of paint. Most acrylic latex paints bond well to plastic, to the point where I don't bother with primer.
My suggestion is to check with your local paint store, as there are many new products and technologies, including paint and primer in one, paints designed specifically for plastics, and various epoxies.
Based on my 20 years of mitigation and 12 years in the remodeling business, I will say that spray paint does not hold up well over time, and that a good bonding primer and acrylic latex topcoat is the best way to go.
FYI, there are small, curved paint rollers available that are made for painting round pipe.

A nice thing about the pipe color matching the building color is that the pipe can be painted in place after installation.

Please ignore the word "ionizing" in my previous comment. Apparently, there is no way to edit posted comments. Thanks,