Radon and seal concrete under tub

[alldodge]

In short: Measuring Radon between 4.1 to 4.5
Basement Tub was installed over gravel base. Concrete is all around it and as to why they did it this way is anyone's guess. Have access to drain side of tub and looking for a way to seal under the tub without removing the tub.

Think about floor leveler, mix large amount and pour under drain end. Not sure if it would make it around all sides and the rear. Also don't think leveler will actually seal anything.

Is there anything on the market that way do what I'm looking for

Have a electronic Radon meter which is listed as highly accurate, is reset-able so it can be moved to other locations for new test. Have moved it around up and down stairs and most all are in the 4.1 to 4.5, max by EPA is 4.0. Did test outside air on porch with 0.5

 

[Scott Danforth]

Liquid epoxy?

 

[alldodge]

Liquid epoxy?

Maybe, like it better then something like Tar. Wounder would expansion and contraction be an issue?

 

[Scott Danforth]

Should be ok. Thinking you will need two pours. First will filter down into gravel a bit.

Second should be able to seal any gaps left over

 

[alldodge]

Wonder how many gallons it would take
Figure a standard tub is 30x60 and don't know if the rear is higher then what I can see. I do have a bore scope so with enough lighting I should be able to make a guess

 

[Scott Danforth]

30x60" x 1" thick is 7.8 gallons

May be able to mix up 4-5 gallons and flood the area

 

[alldodge]

Will do what I have to do, but that much epoxy looks to be maybe $500

 

[Scott Danforth]

How big is the access?

Any way to mix up concrete and use a combination of PVC pipe and a small hoe to fill most, then maybe use epoxy as a cap.

 

[alldodge]

How big is the access?

Any way to mix up concrete and use a combination of PVC pipe and a small hoe to fill most, then maybe use epoxy as a cap.

I can see the entire underside of the front of the tub. If I had a concrete pumper of some kind that might work. Could mix it up real soupy but not sure this would make more a mess then something else

I wonder
Get some 3 LB foam and setup something I can pour from the rear to the front. The 5 LB stuff can break things as it expands. Might be thinking to hard about this. What if I just seal up the front end of the tub? Might be enough to find out if it makes a difference

 

[Scott Danforth]

Not sure I would do expanding foam. You would hear a pop and find your tub a foot higher

 

[dingbat]

Careful with your material selection as Radon can seep through concrete. They make a special epoxy as a concrete sealer

Is there a random mitigation scheme (venting) in place under the slab?

I have a whole network of pipes tied into a vent stack and covered with plastic prior to pouring the floor

 

[Scott Danforth]

I can see the entire underside of the front of the tub. If I had a concrete pumper of some kind that might work. Could mix it up real soupy but not sure this would make more a mess then something else

The soupy mix is what the PVC pipe is for. May need an elbow

 

[alldodge]

Is there a random mitigation scheme (venting) in place under the slab?

House built in 1969, probably before Radon was wildly known. This is my Great Aunt/Uncle retirement home and now its ours. Just decided to test it about a year ago. Found somewhat higher readings with the package tester so bought the higher tech electronic unit.

Now just want to try some passive things to see if something guest it lower before contacting pros