Radon experts?

[Bad LP]

Expansion cuts are there to control where the concrete is allowed to crack thru. It's not a 100% guarantee but it's up there.

If it was my pit I would not disturb it. In a corner or area you don't care about losing some space core a 3" hole thru the slab and run the radon vacuum fan line thru it. I would not do this until after the levels have been retested.

As for your perimeter drains to day light yes, open them up to breathe and they should remain open anyway is order to avoid getting root bound from surrounding vegetation.

 

[Indianawood]

Expansion cuts are there to control where the concrete is allowed to crack thru. It's not a 100% guarantee but it's up there.

If it was my pit I would not disturb it. In a corner or area you don't care about losing some space core a 3" hole thru the slab and run the radon vacuum fan line thru it. I would not do this until after the levels have been retested.

As for your perimeter drains to day light yes, open them up to breathe and they should remain open anyway is order to avoid getting root bound from surrounding vegetation.

Do you think opening them up will have any effect on Radon levels?

 

[peakbagger]

In theory if the perimeter drains are open under the house this should reduce the pressure gradient between the house and the soil underneath the house. The fans are cheap, it would be interesting to set up a water trap on the outlets and pull a vacuum on the perimeter drains upstream of the traps.

 

[Bad LP]

Do you think opening them up will have any effect on Radon levels?

Depends on a lot of factors. You know for a fact the joint along the slab/wall line needs to be done. Take a reading after and go from there.
There is NO WAY I would jump into mitigating with both feet. NONE.

 

[Indianawood]

Depends on a lot of factors. You know for a fact the joint along the slab/wall line needs to be done. Take a reading after and go from there.
There is NO WAY I would jump into mitigating with both feet. NONE.

Are you saying that's the biggest contributor? We've been doing the floor cuts and cracks and so far haven't seen much difference. The wall floor seam is more difficult. I'll have to cut away some foam board and drywall that's been done

 

[Bad LP]

Are you saying that's the biggest contributor? We've been doing the floor cuts and cracks and so far haven't seen much difference. The wall floor seam is more difficult. I'll have to cut away some foam board and drywall that's been done

I know I had to get a brand new spec house done. That was the largest joint.
When we built the house I preplanned having 2 future chases to the attic buried in an exterior wall. It’s cheap at framing. End result was high radon with no ledge nearby. The forethought saved those ugly assed vent pipes running up the side of a 1.3 million dollar home.
Used one for the slab and another for the water mitigation.
Pure luck was on my side.

 

[peakbagger]

I have seen some real hack jobs for radon systems installed in a rush tied to a home sale. Usually the test results come up during a home inspection when there is a conditional offer on the house. The buyer, the seller and the broker are already to make the sale but a high radon test shuts the deal down. Usually the broker recommends a firm to do it quick and on occasion he gets a kickback from the contractor. The contractor installs a couple of pipes and some hi wattage fans and goop up some cracks. The new homeowner ends up with a couple of hundred watts of fans running 24/7 and the seller pays a premium for the work.

The other kick is folks worry about the radon and keep the unvented gas appliances like stoves and ovens which also have long term health consequences.

 

[mewop]

A few points from my recent experience -
I have the same meter posted in the first page. It was dead on with the "professional" meter that was left in our house several days prior to mitigation install and also after the install was completed. I would trust it's reading.

Our concrete slab has zero (can't even find any hairline cracks), perimeter sealed with self leveling caulk, all penetrations for drains caulked, no sump pump, open sink/shower drains normally covered (septic) yet radon was still 25+ at times. It is diffusing through the concrete itself at our house. A good portion of our basement is also subterranean which I suspect is also a contributor. It probably comes through the concrete brick easily given how porous that stuff appears. The wall/floor surface area underground is quite large in our home.

Paid about 1500 for ours. About 50' of 8" PVC and a fan. Honestly could have DIY'd for a third of that but I could not have made it look as professional as they did. Maybe $400 in materials? They really did a great job though.

Since mitigation, I have not seen it over 2 (typically 0.5 to 1 unless heavy rain and cold weather). That little fan is covering about 1800 sq ft of floor plus 1/2 of the basement walls being underground.

 

[rosem]

First things first, pay for a real radon test with a true calibrated instrument, you used yours, it gave you the indication that there was the possibility of something wrong, now get the real test to confirm it then think of remediation.

Agree with this. Your cheap Chinese Amazon tool told you something might be worth looking into. I would pay for a professional test and go from there.

I would think the OAK is helping unless you leave a window cracked all the time.

 

[mewop]

Agree with this. Your cheap Chinese Amazon tool told you something might be worth looking into. I would pay for a professional test and go from there.

I would think the OAK is helping unless you leave a window cracked all the time.

I wish it was cheap. Those meters are $150! It looks like most people reviewing it on Amazon have a similar experience with them as I did - I know my particular unit is calibrated correctly at least - cannot speak to any variation between individual units

 

[rosem]

I wish it was cheap. Those meters are $150! It looks like most people reviewing it on Amazon have a similar experience with them as I did - I know my particular unit is calibrated correctly at least - cannot speak to any variation between individual units

Relatively cheap. Compared to a professional unit.

 

[Indianawood]

A few points from my recent experience -
I have the same meter posted in the first page. It was dead on with the "professional" meter that was left in our house several days prior to mitigation install and also after the install was completed. I would trust it's reading.

Our concrete slab has zero (can't even find any hairline cracks), perimeter sealed with self leveling caulk, all penetrations for drains caulked, no sump pump, open sink/shower drains normally covered (septic) yet radon was still 25+ at times. It is diffusing through the concrete itself at our house. A good portion of our basement is also subterranean which I suspect is also a contributor. It probably comes through the concrete brick easily given how porous that stuff appears. The wall/floor surface area underground is quite large in our home.

Paid about 1500 for ours. About 50' of 8" PVC and a fan. Honestly could have DIY'd for a third of that but I could not have made it look as professional as they did. Maybe $400 in materials? They really did a great job though.

Since mitigation, I have not seen it over 2 (typically 0.5 to 1 unless heavy rain and cold weather). That little fan is covering about 1800 sq ft of floor plus 1/2 of the basement walls being underground.

8" pipe? Is that correct? Most seem to be 3 or 4"
We are about 3/4 done with seams and wall/floor seam. This morning we are at 12. Im starting to doubt that this will be enough. Thinking im gonna have to install a blower mitigation system

 

[mewop]

8" pipe? Is that correct? Most seem to be 3 or 4"
We are about 3/4 done with seams and wall/floor seam. This morning we are at 12. Im starting to doubt that this will be enough. Thinking im gonna have to install a blower mitigation system

Yea I bet it is coming through the floor/walls like ours was. When the sliding door/window was opened it cleared out fast but really built up on those "perfect storm days" when it was cold and the ground fully saturated.

It actually might be 6". It is either 6 or 8". The difference in airflow with 4" vs 6" is more than double - you want to go as big as you can so they don't end up coming back and need to make another run on the other side of your slab. I was worried the single run might not lower it enough. Part of our slab is under the garage/mud area and they noted they can tee into the main run if needed. I have not tested that area but not really worried as that is not "livable area" where we spend any significant time

 

[nortcan]

Hi, not a radon expert but I wonder if having some device to get outside of the house fresh air to create a light positive pressure inside so the radon would not be pulled out from the places it comes from. I supposed it doesn't come from water. If from water you will need an air injection system, there are very simple and not expensive system for aeration just like neutralising sulfur in the water. There are also air ozonator systems but not shure if OK for radon??? I could make some reseaches for it.

 

[DBoon]

It's couterintuitive, but you also should make sure any leaks from your ceiling to your attic are well sealed. The idea is to eliminate the stack effect that pulls radon from the basement into the house and through leaks in the ceiling into the attic. Seal the leaks at the outlet and slow the flow into the basement. The seal up obvious holes in the basement as well.

We had a radon mitigation system installed - $1500, 4" pipe, AC induction powered fan runs 24/7 and consumes about 40 watts/hour. Went from 18 to <2.

 

[semipro]

It's couterintuitive, but you also should make sure any leaks from your ceiling to your attic are well sealed. The idea is to eliminate the stack effect that pulls radon from the basement into the house and through leaks in the ceiling into the attic. Seal the leaks at the outlet and slow the flow into the basement. The seal up obvious holes in the basement as well.

We had a radon mitigation system installed - $1500, 4" pipe, AC induction powered fan runs 24/7 and consumes about 40 watts/hour. Went from 18 to <2.

At $0.10/kWh that's $35/year for power - not too bad just for fan operation.

 

[Indianawood]

Update. Making great progress!
Got up this morning and we are down to 5.45. We have most of the floor cuts/cracks sealed. Started on wall/floor crack yesterday. About 1/2 done. Finishing today.
For anyone reading this in the future. By far the wall/floor seam made the biggest difference. Once we started that yesterday the levels dropped all day.
Where the seam was accessible i cleaned, dried, and caulked it. Where there was foam board and drywall i cut bottom 1" away and spray foamed with closed cell foam.
Finishing today. I'll post another update

 

[peakbagger]

My guess is that running a fan 24/7 365 is overkill but simple. It would be interesting to set up a data recorder and see what the trends are over the long term especially summer time when the heating system is shut down and the house is more opened to the outdoors. My guess is radon in soil diffuses quite slow through the soil and once the system had been running for awhile 24/7 that the levels will drop to the point where the fans could be cycled on an off. Of course this introduces complexity and expect most systems are designed for KISS operation.

I personally would be interested in seeing how solar powered DC fans would work. I have A DC pump on my Solar Hot Water system and its been running over 20 years with no intervention.

 

[Indianawood]

Couple of pictures from today and likely the biggest offenders, the wall/floor and relief cracks

 

[faultymechanics]

New house we just bought has a proper mitigation system put in. I can tell you if you sell your house and it tests anywhere over 4 the buyers won't touch it without a proper system being installed and reading being under 4. In fact my wife and I said the system has to be under 3 (which it ended up fulfilling) because the World Health Organization says anything over 2.8 should be considered actionable.

You also need to test your water if you have a well. You're talking about something that can cause cancer...I wouldn't mess around. Yeah $1500 is a decent chunk of money but hospital costs are way more. Also consider the levels are estimated to halve each floor above the basement. So even at 5 in the basement you'd be seeing 2.5 on your first floor. Are you comfortable with that?

It seems like sealing your cracks is helping which is great and you may get away with doing what you're doing. Just make sure you give the house an entire week after sealing all the cracks to level out. Also you shouldn't be opening doors and windows in the basement otherwise that will throw off the test.

Official Radon tests are left in the basement for around 4-5 days I believe to give you a range of readings as it generally isn't consistent.

Our system had the company drill a hole in the slab, run the piping out the side of the house using a fan to blow it out above the roofline and I feel way better about the time I spend in then basement, which is a lot. It also has a meter on the side so I can always check the levels in the basement to ensure it's functioning properly.

Just my 2 cents, take it for what you'd like.


P.S. Any Mitigation company worth their cost will be sealing all of those cracks as well as installing the system. Can't get a good vacuum with all those cracks open.

 

[nortcan]

New house we just bought has a proper mitigation system put in. I can tell you if you sell your house and it tests anywhere over 4 the buyers won't touch it without a proper system being installed and reading being under 4. In fact my wife and I said the system has to be under 3 (which it ended up fulfilling) because the World Health Organization says anything over 2.8 should be considered actionable.

You also need to test your water if you have a well. You're talking about something that can cause cancer...I wouldn't mess around. Yeah $1500 is a decent chunk of money but hospital costs are way more. Also consider the levels are estimated to halve each floor above the basement. So even at 5 in the basement you'd be seeing 2.5 on your first floor. Are you comfortable with that?

It seems like sealing your cracks is helping which is great and you may get away with doing what you're doing. Just make sure you give the house an entire week after sealing all the cracks to level out. Also you shouldn't be opening doors and windows in the basement otherwise that will throw off the test.

Official Radon tests are left in the basement for around 4-5 days I believe to give you a range of readings as it generally isn't consistent.

Our system had the company drill a hole in the slab, run the piping out the side of the house using a fan to blow it out above the roofline and I feel way better about the time I spend in then basement, which is a lot. It also has a meter on the side so I can always check the levels in the basement to ensure it's functioning properly.

Just my 2 cents, take it for what you'd like.


P.S. Any Mitigation company worth their cost will be sealing all of those cracks as well as installing the system. Can't get a good vacuum with all those cracks open.

Thanks for all those details.

 

[Indianawood]

New house we just bought has a proper mitigation system put in. I can tell you if you sell your house and it tests anywhere over 4 the buyers won't touch it without a proper system being installed and reading being under 4. In fact my wife and I said the system has to be under 3 (which it ended up fulfilling) because the World Health Organization says anything over 2.8 should be considered actionable.

You also need to test your water if you have a well. You're talking about something that can cause cancer...I wouldn't mess around. Yeah $1500 is a decent chunk of money but hospital costs are way more. Also consider the levels are estimated to halve each floor above the basement. So even at 5 in the basement you'd be seeing 2.5 on your first floor. Are you comfortable with that?

It seems like sealing your cracks is helping which is great and you may get away with doing what you're doing. Just make sure you give the house an entire week after sealing all the cracks to level out. Also you shouldn't be opening doors and windows in the basement otherwise that will throw off the test.

Official Radon tests are left in the basement for around 4-5 days I believe to give you a range of readings as it generally isn't consistent.

Our system had the company drill a hole in the slab, run the piping out the side of the house using a fan to blow it out above the roofline and I feel way better about the time I spend in then basement, which is a lot. It also has a meter on the side so I can always check the levels in the basement to ensure it's functioning properly.

Just my 2 cents, take it for what you'd like.


P.S. Any Mitigation company worth their cost will be sealing all of those cracks as well as installing the system. Can't get a good vacuum with all those cracks open.

All cracks sealed.
4"dc duct fan hooked to foundation perimeter tile.
Perimeter tile has been unused and buried since 2003. Figured I'd give it a try.
Im gonna turn off today and monitor levels for a few days to see if the ventilation is necessary.

 

[peakbagger]

All cracks sealed.
4"dc duct fan hooked to foundation perimeter tile.
Perimeter tile has been unused and buried since 2003. Figured I'd give it a try.
Im gonna turn off today and monitor levels for a few days to see if the ventilation is necessary.

View attachment 272531 View attachment 272539

Great news. You may end up being able to cycle the timer. Or you can try my concept and get a DC fan and hook it to a solar panel. Whenever the sun is out the fan runs when its not out it doesnt.

 

[Indianawood]

Great news. You may end up being able to cycle the timer. Or you can try my concept and get a DC fan and hook it to a solar panel. Whenever the sun is out the fan runs when its not out it doesnt.

Im hoping i don't need the fan. If i do i did get a dc fan so it has 10 speeds. I'll find a speed that is sufficient.

 

[Indianawood]

Update #2
Turned off fan. Took about 2 days and radon levels returned to about 5 range. Looks like sealing all the cracks got us from 15 to 5.
Within hours of turning fan on levels began to drop again.
Turned fan to 50% speed to see if that will maintain low levels.
Fan is only using 5 to 5.3 watts on 50%