Retrofitting radon barrier?

toastedpickles

Howdy peoples

Just curious, is it possible to retrofit a radon barrier? Or any other means of prevention?

Thanks

phormium

Not that I know of, would require taking up floors surely so not a great plan even if it worked.

I had my house tested years ago now and it was high, I got 3 different quotes for remediation work varying from 2.5k to 5k at the time time. Having done a lot of research I went for the cheaper option which started at an even lower rate initially, as in they installed vents in the house and a pump thing in the attic to pump air in, the theory being that it would increase the pressure inside thus preventing the radon gas from coming in, anyway it didn't work and the noise of it drove me mad, that option had it worked was around 1k.

Next option was to make a sump outside the back wall of the house and fit a pipe and fan, I had the house tested after doing it and it did reduce the levels substantially to below guidelines. I watched the guy do it and quite honestly had I known it was that simple I would have done it myself with the help of a family electrician which you would need. He basically cut a hole in the path, dug down through the rubble under the house, put in a plastic pipe, ran it up the wall to about 2 ft over wall plate level, fitted a plywood box with a fan in it just below roof level, ran wire into attic and connected it and screwed it shut. Filled in the hole around the pipe with concrete, I was quite astonished at how basic a system it was for 2.5k and a days work. Fan is on continuously works and is definitely heavier on electricity than they would lead you to believe.

One of the other companies insisted that the sump had to go in the middle of the house and they wanted to dig up floor in kitchen and run pipe along inside wall and up through attic and out, a much messier and bigger job. The crowd I went with said outside back wall of house would do so I preferred that option. I did not have to pay until tests confirmed it had worked.

toastedpickles

Hmm ok, well taking up floors isn't an issue, we were discussing it there today so it's an option, but your method sounds pretty good!

phormium

I don't know for sure but I don't think even taking up floors fixes it, in a new build to the best of my knowledge the barrier goes all across the foundation and under all the walls, that would be impossible in an existing house, you would be just doing each room and that wouldn't solve the problem.

toastedpickles

phormium wrote: »

I don't know for sure but I don't think even taking up floors fixes it, in a new build to the best of my knowledge the barrier goes all across the foundation and under all the walls, that would be impossible in an existing house, you would be just doing each room and that wouldn't solve the problem.

Yeah that's what I was thinking myself, I thought a retrofit was bit far fetched with that kind of thing

phormium

Apart from anything else I know of loads of newer houses than mine that were built with the barrier installed and they still have high levels. Many have had to do further work to them to reduce the levels. I live in an area of high radon in general. My house is 20+ yrs old but much newer estates around me have tested high despite all of them having been built since regulations required barriers. It must be hard to install them correctly if so many don't work.

toastedpickles

phormium wrote: »

Apart from anything else I know of loads of newer houses than mine that were built with the barrier installed and they still have high levels. Many have had to do further work to them to reduce the levels. I live in an area of high radon in general. My house is 20+ yrs old but much newer estates around me have tested high despite all of them having been built since regulations required barriers. It must be hard to install them correctly if so many don't work.

Our house was built in the 40's so, building regs were never heard of, but we're slowly getting it up to code, the only reason they don't work is they aren't sealed up around piping and the like i'd guess

bbam

phormium wrote: »

Apart from anything else I know of loads of newer houses than mine that were built with the barrier installed and they still have high levels. Many have had to do further work to them to reduce the levels. I live in an area of high radon in general. My house is 20+ yrs old but much newer estates around me have tested high despite all of them having been built since regulations required barriers. It must be hard to install them correctly if so many don't work.

Many cowboy builders laid strips of barrier over the existing foundations to give the appearance of a full barrier, would pass engineer inspection no bother.

I've also seen flooring crews intentionally puncture radon barriers to let excess water down to make laying floors easier.

I laid my own barrier and it's not that hard to lay, just time consuming. Took 8 hours on a pissy wet day. Horrible job.

Fries-With-That

phormium wrote: »

Fan is on continuously works and is definitely heavier on electricity than they would lead you to believe.

Would it be possible to change your electric fan for a wind operated cowl, like some people have on their chimney.

phormium

Doubt that it would be efficient and consistent enough to do the same job.

tommykeane45

u went for cheapest option ,cant believe it wasnt top class job ? amazing

red sean

tommykeane45 wrote: »

u went for cheapest option ,cant believe it wasnt top class job ? amazing

Welcome to boards. You seem a helpful chap :rolleyes:

Audioslaven

toastedpickles wrote: »

Howdy peoples

Just curious, is it possible to retrofit a radon barrier? Or any other means of prevention?

Thanks

Hi,

I was doing up my house and we dug up the floors. We put in two sumps and joined them together with pipes and had the output outside.

We then placed plastering sand on the floors and laid the radon barrier on this. We used a tar based tape to seal the radon barrier to the wall. The wall was cleaned off to get a good seal. The radon barrier also acted as a damp proof course.

We then put insulation over this and poured with floor screed. I am in a high radon area but I didn't get the house tested before the work. I did get it tested afterwards and it was low so I was happy with it.

Audioslaven

Homefarm

Have a 200+ year old granite building with earth floors covered by a thin crust of concrete (1cm). As they're leaky, we needed to reinstall floors with a radon+water barrier. We're in a high risk radon area and groundwater is only a foot down.

A sump solution was impossible as the digging we'd have to do to install a decent depth of hardcore would likely upset the foundations of our two-storey building. Even an edge sump requires hard core under a slab.

We opted to dig down minimally and install a radon barrier sealed to the internal walls, below a well insulated floating floor. We unearthed old wall vents, and installed a few more with the view of keeping the airspace between the radon barrier and floor well ventilated. This is in case radon gets through.

We're just finishing this job now and I'll report back on readings. We figure we still have the option of installing a fan or negative pressure cowl on a vent pipe to assist with circulation, if required.

I'm sure were not the only ones without hardcore in an old house. It did put a spanner in the works for our plans to lay hemp-lime screed floors, but hopefully our solution is equally effective, whilst still utilising natural materials.

I'd love to hear from others about their experiences retrofitting very old buildings.