I don't envy your task. Items 1 to 3 seem straight forward enough but items 4 and 5; wow! Good luck. As we all know Items 4 and 5 can certainly be done but trying to find a low cost solution and provide accurate cost estimates will be difficult. I wonder, would you have some luck discussing the pros and cons with the client? If you explain that passive Rn controls have low effect and the challenge and cost with sealing rubble walls they may be more inclined to go to an active system. As Jay eluded active slab depressurization seems to work in controlling radon intrusion through rubble walls for him.

If the walls prove to be a significant source of Rn intrusion, even after sub-slab mitigation, you could consider an active wall system ( e.g. depressurize or pressurize a cavity created by dimple board placed on the interior of the rubble wall). The active system would manage any imperfect seals in the dimple board. You could have the cavity drain to the soils below by drilling holes through the slab at the base of the wall and ensure the dimple board covers the holes. Make sure you drill enough holes to manage the anticipated water and get the low spots in the floor. You would need to make sure that the negative pressure under-slab is greater than the negative pressure on the wall cavity so that water pooled at the bottom of the wall is not slurped up into the wall because of back-draft up the drainage hole. Again there is lots of buildings science to consider with pulling or pushing air/soil gas through the foundation wall. If you pull too much cold air in from outside you could cause some wall freezing. If you pump too much warm air into the cavity you could warm the exterior soils in the winter (no so bad but lots of energy loss).

Dick. I know Bob very well and we talk about this stuff all the time. I am a certified Building Scientist and Certified Engineering Technologist in the Civil discipline. I don't know the full scope of your task or budget expectations which put me at a disadvantage. The foam is simply a tool to provide a very effective air barrier/radon barrier. It is an option to use or disregard as you see appropriate to your project parameters. You are correct that the insulation is not "needed" but in your case the foam is the radon barrier/membrane and the insulative value is just a side benefit. In Bob's example (and likely Joe's for that mater) I am sure the drainage plane (dimple board) was not sealed and they relied on the foam as the seal. You could try and manually seal a rubble/stone foundation wall manually but I would expect labour cost to be very high and efficacy of the seal to be very low. A low seal efficacy would not be good particularly if you are looking for passive controls as you indicate is the goal. But perhaps there is a migrator out there who can do an adequate manual seal at reasonable cost. Building Science is a very, very, very complex thing. Managing moisture and it's movement in any building envelope needs to be considered carefully as do budget implications. In Joe's French drain configuration he is managing moisture in the wall and providing a free and clear drainage path to the subsurface. It is important to not that you would still have to provide a membrane barrier on a rubble wall a place to drain any accumulated water as you can't simply let it pool at the bottom of the wall with no where to go. Lstiburek and his firm is available to consult on projects.

David is correct. Czech Institute in Prague is best bet. My contact there was Martin Jiranek email jiranekatfsvdotcvutdotcz

I agree that anyone can tamper with a device if they set their mind to it. For the tyvek bags I suggest you contact Eperm. If I recall correctly they supply them and have done a comparison. SInce the tyvek is vapour permeable (full of tiny holes to let the water molecules through) Rn will pass through it since Rn is 200 picometers in diameter and water is 275. In this cas it is a diffusive transport through the media.

Good point Jeff. Things need to stay civil. We all remember why the last list server was shut down and I don't want that happening to this list serve.

Safety Siren did a lot of work in this field which got more people testing for radon and which brought value to the industry and I think they deserve credit for that. I don't believe the manufacture ever pushed that the Safety Siren was a CRM or that it should be used as such.

If we keep in mind the intent and purpose of the Safety Siren we realize it does its job as it was designed to. All devices have their limits and intended use and as such are not good or bad per say. This is the same for any air quality monitor out their. All manufactured devices are subject to wear and tear. Remember smoke and CO detectors also eventually fail but I still sleep better knowing I have them. I have always specified a Safety Siren or equivalent in all my mitigation designs so that occupants are left with a warning device should something go wrong with the mitigation system. There are newer electronic home radon monitors on the market that also function within the intended design and purpose but they will have their own set of limitations, again not good or bad per say. In my opinion and experience in indoor air quality most of the issues with direct read instruments is not the fault of the device but the fault of the user not using the device properly.

My home Safety Siren was reliable until it past it's warranty period and sensor failed. My neighbour had one that post mitigation was readying around 150 to 180 Bq/m3 (4 to 5 pCi/L). I used two RSSI alphas co-located beside the instrument and the RSSi's reported radon around 15 to 20 Bq/m3.

I watched the video and I am a bit confused/concerned about the causal link. I need a MD experienced with Rn illness to confirm. The video said she had fibrosis not lung cancer and it plays out like her family made the link (accurate or not) between her illness/death and radon.

The Mayo Clinic says the following about fibrosis "Pulmonary fibrosis is a lung disease that occurs when lung tissue becomes damaged and scarred. This thickened, stiff tissue makes it more difficult for your lungs to work properly. As pulmonary fibrosis worsens, you become progressively more short of breath. The scarring associated with pulmonary fibrosis can be caused by a multitude of factors. But in most cases, doctors can't pinpoint what's causing the problem. When a cause can't be found, the condition is termed idiopathic pulmonary fibrosis."

I like that the video helps highlight the risk of radon but it is important that causality is accurately stated. My concern is the link the Dr. made may be too much of a reach. We are already fighting disbelief of the risk of radon and improper connections between radon exposure and adverse health affects will only serve to harm progress in changes of opinion.

Hi Sam

I need some clarification on your comment. In those situations is the attic occupied and tied to the building ventilation or simply insulated? I think it makes a difference as the point (as per US guidelines) of not putting the Rn fan in a conditioned space is to prevent Rn leaking into an "occupied space" where occupants could be exposed. An attic that is insulated for energy benefit may not necessarily be occupied or occupiable and should not be coupled to the living space. So I am not sure if the term conditioned is being properly applied or thought through. In this case forbidding an Rn fan in the (only insulated) attic I think is an incorrect interpretation. I just want to make sure I understand the intent and science and am not caught up in definitions (rightly or wrongly applied) that are forbidding a viable solution. In Canada our guidance allow for indoor radon fans in the basement. I always spec the install of a radon alarm with all my active systems to guard against leakage.

I have seen the City of Guelph, Ontario, Canada implement a very effective RRNC program. It had builder hick-ups at the start but people were learning. Many of the problems I see professionals point out about are 100% valid and I agree wholeheartedly. The root cause of the issue is that the Building Authority can only enforce Building Code. If Building Code (or other legislation) does not make testing mandatory then builders won't do it. If code allows for poor quality and improper installation because it is unclear or incorrect then these issues will continue. Legislative changes take time and are under political influence. If we, and the government in power want occupant safety and a healthy community legislation must change.

I understand the frustration. What keeps me going is the positive fact that radon is being discussed more often which leads to better public awareness. If you have 55% failure in builder pipe then you have 45% success which is more than 0% anything like we had ten years ago.

I do agree that there are short comings to RRNC and unskilled trades and ill informed people are among the main reasons for poor results. We are here to sort those out.

The website states "Professionally certified lab analysis fees and USPS Priority shipping are included in the purchase price." So it looks as if this is just a simple sampling DIY. At least it is lab analysis. I have sampled for all of these compounds and a DIY kit for this kinda scares me. Getting data is one thing but properly interpreting exposure is very different. This could be a GIGO test result. At the cost they are advertising it is not much more to have a professional do it properly. I do not see the benefit of this product.