Radon reduction cost for soil based radon
Hello friends,
Apology for writing this partly in English.
I am in process of buying a house which has a high radon concentration 440 + - 60 Bq / m2 Arsmedelvlrde
My questions are
1. Is it possible to lower it below 100 bq / m3?
2. What can be the maximum cost in worst case scenario?
3. The plot is displayed as an area with high radiation (6.3) when I view it in https://apps.sgu.se/kartvisare/kartvisare-uranstralning.html , are these type of areas avoided by buyers?
Below is the radon measurement report, I received after the radon test.
Measurement with Alpha-Guard gave results at floor moldings and kryppgrund
Floor • t bedroom 653 bq / m '
Creeping ground 798 bq / m '
Long term measurement Oct - Jan
Bedroom 430 +/- 60 Bq / m3
Living room 440 +/- 60 Bq / m3
Ventilation observations:
Lack of fresh air vents in the property's bedroom / living room.
The ventilation is considered to function as intended (Natural), but not from a radon perspective.
Gamma measurement of building materials indicated low radiation in all walls of the property.
The property has a municipal water supply, which means that water can be excluded as a source.
Because water and building materials could be excluded as sources of radon, the land is considered to be so
only remaining factor to the elevated radon gas content.
Measurement with Alphailuard gave results at floor moldings and creeping ground (see ground air leaks).
In addition to the house's ventilation system, the air exchange in a building is determined by the wind's impact on the house.
as well as by ventilation. These factors also affect the indoor air pressure, which in turn affects the flow -
of radon-containing soil air into the property.
Step 1
Sealing and creating negative pressure.
Cover the crawl space with age-resistant plastic.
Installation of two pressure / moisture-controlled fans type Security guard PRO-X and one heating loop.
Discharge of air takes place via existing ventilation holes in the crawl space.
The installation will create a negative pressure in the crawl space and suck it out
radon gas-containing soil air.
Alt 2:
Installation of a mechanical exhaust and supply air system with heat exchanger, FTX system.
By balancing the flow of supply and exhaust air, the system can greatly increase air circulation
at the same time as the air that comes out of the house is slightly heated.
Step 2:
Carry out a new long-term measurement with trace film during the heating season. (October 1 - April 30)
Step 4:
Installation of supply air devices in the living spaces where it is missing.
This contributes to an increased air turnover, a reduced negative pressure and thus a slightly reduced radon gas content.
Apology for writing this partly in English.
I am in process of buying a house which has a high radon concentration 440 + - 60 Bq / m2 Arsmedelvlrde
My questions are
1. Is it possible to lower it below 100 bq / m3?
2. What can be the maximum cost in worst case scenario?
3. The plot is displayed as an area with high radiation (6.3) when I view it in https://apps.sgu.se/kartvisare/kartvisare-uranstralning.html , are these type of areas avoided by buyers?
Below is the radon measurement report, I received after the radon test.
Measurement with Alpha-Guard gave results at floor moldings and kryppgrund
Floor • t bedroom 653 bq / m '
Creeping ground 798 bq / m '
Long term measurement Oct - Jan
Bedroom 430 +/- 60 Bq / m3
Living room 440 +/- 60 Bq / m3
Ventilation observations:
Lack of fresh air vents in the property's bedroom / living room.
The ventilation is considered to function as intended (Natural), but not from a radon perspective.
Gamma measurement of building materials indicated low radiation in all walls of the property.
The property has a municipal water supply, which means that water can be excluded as a source.
Because water and building materials could be excluded as sources of radon, the land is considered to be so
only remaining factor to the elevated radon gas content.
Measurement with Alphailuard gave results at floor moldings and creeping ground (see ground air leaks).
In addition to the house's ventilation system, the air exchange in a building is determined by the wind's impact on the house.
as well as by ventilation. These factors also affect the indoor air pressure, which in turn affects the flow -
of radon-containing soil air into the property.
Step 1
Sealing and creating negative pressure.
Cover the crawl space with age-resistant plastic.
Installation of two pressure / moisture-controlled fans type Security guard PRO-X and one heating loop.
Discharge of air takes place via existing ventilation holes in the crawl space.
The installation will create a negative pressure in the crawl space and suck it out
radon gas-containing soil air.
Alt 2:
Installation of a mechanical exhaust and supply air system with heat exchanger, FTX system.
By balancing the flow of supply and exhaust air, the system can greatly increase air circulation
at the same time as the air that comes out of the house is slightly heated.
Step 2:
Carry out a new long-term measurement with trace film during the heating season. (October 1 - April 30)
Step 4:
Installation of supply air devices in the living spaces where it is missing.
This contributes to an increased air turnover, a reduced negative pressure and thus a slightly reduced radon gas content.
My experience is that radon from the soil/ground is not difficult to fix.
The proposed method, creating negative pressure under plastics in the crawl space and vent it out is probably very effective and my experience is that you dont need to use purpose built and often expensive fans for it.
I prepared a suction pipe under the concrete floor in the basement when I rebuilt it - immediately after starting the fan (a cheap fan running low rpms) radon whent from 350 to 40-60bq. You have a similar situation but easier to get a suction pipe in place....
Recently I used the fan for other purposes and measurements went up to 350-400 again but after less than 24h of running the fan, radon levels dropped by 100bq. So, even the smallest negative pressure has a very good effect on radon levels. Reason for higher levels now compared to before is that concrete floor is gone in half the house.
And to answer your questions:
1. I dont think its a problem to get it bellow 100bq
2. If i do it myself I would estimate the cost to 2-3000SEK. Fan=1500sek, plastic=600, some drain pipes=500.
3. I think buyers to some extent avoid houses with radon in the building material (because its a lot more difficult to fix), but typically not soil based radon.
The proposed method, creating negative pressure under plastics in the crawl space and vent it out is probably very effective and my experience is that you dont need to use purpose built and often expensive fans for it.
I prepared a suction pipe under the concrete floor in the basement when I rebuilt it - immediately after starting the fan (a cheap fan running low rpms) radon whent from 350 to 40-60bq. You have a similar situation but easier to get a suction pipe in place....
Recently I used the fan for other purposes and measurements went up to 350-400 again but after less than 24h of running the fan, radon levels dropped by 100bq. So, even the smallest negative pressure has a very good effect on radon levels. Reason for higher levels now compared to before is that concrete floor is gone in half the house.
And to answer your questions:
1. I dont think its a problem to get it bellow 100bq
2. If i do it myself I would estimate the cost to 2-3000SEK. Fan=1500sek, plastic=600, some drain pipes=500.
3. I think buyers to some extent avoid houses with radon in the building material (because its a lot more difficult to fix), but typically not soil based radon.
Redigerat:
You can get up to 25 000 SEK in contribution for sanitation of radon (radonsaneringsbidrag). I got 25 000:- for installing a FTX system.
A "radonsug" is not very expensive if the radon comes from the ground through cracks in the concrete etc. If the house is built by "blue-concrete" (light-concrete) air circulation is the answer.
We have a combination of ground radon and blue-concrete.
Before we bought the house the previous owners installed a "radonsug" (in 2007) that lowered the value from approx. 700 to 300. Two years ago we installed a FTX system that lowered it from 300 to approx 100 bq.
More details here:
https://www.boverket.se/sv/bidrag--garantier/radonbidrag/
A "radonsug" is not very expensive if the radon comes from the ground through cracks in the concrete etc. If the house is built by "blue-concrete" (light-concrete) air circulation is the answer.
We have a combination of ground radon and blue-concrete.
Before we bought the house the previous owners installed a "radonsug" (in 2007) that lowered the value from approx. 700 to 300. Two years ago we installed a FTX system that lowered it from 300 to approx 100 bq.
More details here:
https://www.boverket.se/sv/bidrag--garantier/radonbidrag/
neil1983 skrev:
Really sad I missed this thread when it started. Fighting radon is both interesting and fun, even though it might take lots of efforts. Expensive? Depends of the amount of time and efforts you want to add to it. A workable solution will cost a couple of thousands if you perform it yourself (2000-5000). I wrote a large thread about this some years ago (searchable at this forum). We had close to 1000 in values inside most rooms in the house. My radon detectors are now showing an average of below 100 but...that is in the suspended foundation (what you call creeping ground). In the house, average is around 40. In the suspended foundation I had a couple of thousand before starting. Between 1000-3000 at the most.
I was advised to install several different solutions. But installing something replacing lots of air (big suction fan) will in some (most?) cases give you problem with high humidity. That will cause a need for a dehumidifier.
I read all forums I could find and realized that (as mentioned by another writer below) the solution in case of concrete based ground was to add a negative air pressure. Generally giving good results. At least decreasing values 50-75 % or so. Generally that would be enough to get lower than the 200 limit (depending on what values you start with of course).
Applying that theory using plastics does work. But only if you do it the right way and if you make it completely air tight. This sounds easy. And it actually is as long as you are careful and thorough during the job. This applies to everything. Ground, lower walls (if under soil) and all pipes. I found lots of information/recommendations regarding sealing pipes going from the suspended foundation and up in the house. I agree, that is really important. But it is also important to seal all pipe pieces if you have your own sedimation tank. The amount of radon from that tank can be pretty much. Each time someone flushes toilet, air is pressed back into your pipes. And if you have (as I do) three neighbours using the same sedimation tank....there are lots of flushing.
I used these articles:
* Butyl rubber (17 units á 300 grams)
* 350 metres of T-flex green tape (I would not recommend anything else in this case)
* 75 meters of draining pipe (90-110 mm)
* Age resistant plastics, 250 m2
* 2 x 7 watts Pax fans (I tried cheaper ones. They will not last)
* Time, lots of it
My general recommendation is to not touch too much regarding air renewal in the suspended foundation. Replacing air is not always good. Especially not parts of the year here in Sweden and not in that specific area of the house.
Earlier threads discussing parts of this, along with picture/s, below. I got more details if needed.
https://www.byggahus.se/forum/threads/radon-i-krypgrund-loesning-med-extremt-lite-luftombyte.323535/
Also notice that radon values can fluctuate extremely in a short amount of time. You made long time measurement and that is the value to fight against. If you measure after some work has been done, you need to measure for some time and not only right after work/adjustments are made.
I also wrote stuff about the product for measurement I use. I do recommend those. I use 2 in order to calibrate them towards each other. You cannot really "calibrate" but it might happen they show strange values and needs restart once per year or so. Easy to see when needed if you got two. Not so cheap of course but a pretty good investment that keeps track of your work afterwards. As they also keep track of temp and humidity, you will see if you are able to also improve the humidity in the suspended foundation.
My solution worked really fine in this house. You might of course get different results in another house, but if all of your issues relates to the soul, this should work for you too.
When it comes to "radon areas" in Sweden, I would say most places of Sweden have these issues in cases houses were not built with the intention of solving this from the beginning. Seems whole Sweden rests on Uranium foundation.
Another important check to do is ti inspect other areas of the house maybe having concrete floor (in my case a storage room om 10m2 and a garage of 20m2). I needed to seal the concrete floor in those areas. I had a huge amount of radon leaking into other parts of the house, causing even higher values in rooms.
I cannot guarantee exact numbers here but I would guess that below numbers is a good estimation of what my different kinds of sealing gave to the total result:
1. Complete sealing in the suspended foundation using plastics, including fan under pressure solution 70%
2. Sealing all the pipes (yes, all parts of them) 10%
3. Sealing garage and storage room 10%
4. Sealing parts of walls and cracks using normal foam 5%
As you can see, 5% is not counted for. That is the amount I have to live with, still.
Our water contains the level of 500. It does not affect the air so much it seems (in our case) but it is generally said that 5-10% of it can "pollute" the indoor environment and casue raise of the radon levels.
I think it is important to have a plan how to solve radon issues before buying a house. But me personally would not avoid buying a house because of the levels. It can be solved. I would rather look at the water values. Our house had issues with Uranium in the water. That cost a lot more to fix than radon as I could fix radon levels myself.
I would really appreciate to know how you move on with your project and the results from it (if you buy the house)
