Should you seal all rods and penetrations for a radon barrier?
Is it worthwhile to plug all rod holes with hydrolic cement and also apply a product like Radon seal to provide a water and gas barrier before installing xps foam panels on the interior basement walls?
Yes, to reduce radon levels in homes and have an effective radon barrier, you would need to seal all holes protruding through the radon barrier or membrane. And by that, please know I mean ‘do your best’ of course, if you miss one or something it isn’t the end of the world, it’s a cumulative effect. Here is our page about radon barriers, check here for more help –
How to Control Radon Gas in Homes
I do have a few questions though, is this new construction or renovation? Making sure the walls are sealed is an important part of radon mitigation, but it is for sure secondary to the floor. Is there a barrier below the slab floor? And did you have the air levels tested and found it to be high? There are different ways to deal with radon in basements, depending on whether it's finished or not.
High levels of radon in homes can also come from your water if you happen to be on a well, you can read more here –
How to Remove Radon Gas from Drinking Water
I hope that helps, let me know if we can do more.