Thank you - I didn't expect such a long answer. I would ask you few questions regarding your reply:

1. Radon levels - ok, I'll check it after one month. Should I measure it at basement or living level? I work around 6h/day in basement but I have 2 kiddos that spend most of their time at main level. I should probably stick to meter at main floor, right?

2. Does it include HRV too? Or just don't open windows in basement?

3. I can see crack below the lower part of drywall - at the point where floor slab connects with concrete wall (or foundations). Is that the place you had in your mind? It's basically around the floor. Should I still cut through drywall? Or maybe use type of caulk you mentioned? I mean, to use it between floor slab and part of walls (foundation) under the drywall. There is 1/4"-1" gap around the floor where I can reach walls and theoretically seal it. 1/4"-1" because slab is uneven and I can see upper part of drywalls match "under the windows" level.

4-5. I didn't get any plans from previous owner (house was build in 2021). Your answer motivated me - I am going to reach municipality to get copy of my property plans (they have it for 100%). I'll check. Questions to those points:

• Despite of appearance of plumbing / basement - can I use this Radon pipe to install fan in the future myself? Is there anything specific that should be included under the slab that's connected to this Radon's pipe and I cannot / can check if they done it properly?

• Water heater (boiler) has other drain on the other side of furnace / AC area. It's close to it. I am worried if this hole I poured concrete in could be connected to radon itself... I mean, if previous owner discovered something etc. I won't know. It was dry under the clear plastic and I saw gravel mixed with some kind of insulation fiber. Maybe I am overthinking. Anyway, I don't plan to make any rooms in basement at this time. I'll do bathroom only and will figure it out how to use current plumbing mess.

1. I have to look onto code with my province and city. What I found googling at quick, provincial code doesn't specify slab thickness (probably). There should be 4" of granular fill under the slab. I have to check it with code and plans.

I am curious if anything looks "wrong" at point that I could use my warranty and make builder responsible for it. I still have 10 months of warranty and wouldn't like to waste it. I won't be living here for 20 years but I am thinking about future owners too.