Radon Barrier

Twinkle Toes

My builder has put down radon barrier firstly instead of taking radon over the the floor edge block he took it under it. This was bad enough but when I went home yesterday he had trimed all around the edge of the inner leaf so it dosn't reach the outer leaf of the footings as a result there is no DPC. My Engineer said this could only be rectified by torching felt on? Does anyone know a better way or have they done this before?

galwaydude18

Have you the floor slab layed yet?

Twinkle Toes

Yes afraid

galwaydude18

Id make him dig it up and relay the radon barrier properaly if I were u at his cost. Y should you pay him for shoddy work?

Twinkle Toes

I would only he's a friend of a friend and was doing it more of a favour!!! Some favour!!! I need to get a solution for problem instead.

galwaydude18

Radon can cause cancer so I if was you I wouldnt care if hes a friend of a friend and was doing it more of a favour! It's wrong and incrorrect and at the end of the day its your health and familes health thats at risk because of this major mistake.

Mellor

this is a serious problem
are you in a high radon area? i'm take this twices as serious uf so
also the radon barrier shouldn't be used as a DPC. it should exit the outer leaf at GL and the DPC should be installed at least 150mm up the wall.
Is the outer leaf started, if not you could use a bitumenous compound and torch on felt to extend the barrier out to the outer leaf. build the outer leaf, installing a DPC at correct height

golden

Here is a link from the radiological Protection Institute of Ireland
http://www.rpii.ie/radon/maps/map.html. You can click on your county and see where your townland is it will give you what the radon levels are

Ewan

the radon barrier is sometimes taken a block or usually a soap brick below ground floor f.f.l to avoid damage from power floating the slab.....is this what your builder has done....?

Twinkle Toes

From the map it says I'm <1%. (Cheers Golden) The local school had radon levels tested and levels were very low.

Ewan the radon barrier is a soap below finised floor level. Instead of taking the barrier over the top of the block at finished floor level he took it under it.

Mellor this looks like my only solution is this expensive?

galwaydude18

No not expensive for you expensive for the cowboy that put the radon barrier totally arse ways and incorrectly. you should be making him pay to correct it and not one cent should you give to have it corrected!

smashey

Twinkle Toes wrote:

From the map it says I'm <1%. (Cheers Golden) The local school had radon levels tested and levels were very low.

Ewan the radon barrier is a soap below finised floor level. Instead of taking the barrier over the top of the block at finished floor level he took it under it.

Mellor this looks like my only solution is this expensive?

Time for you to stop being Mr. Nice guy. The builder screwed up. He pays to get it fixed properly. End of story. It doesn't matter who he is or who he is friendly with, if he can't do the job, he should consider another career.

galwaydude18

Look your only option in my view and probably a lot of peoples as well is make him dig up the slab and get him to put it down correctly! As smashey says "Time for you to stop being Mr. Nice guy. The builder screwed up. He pays to get it fixed properly. End of story."

I don't care if the radon level is only <1%. There is still a serious risk of radon gas leaking and causing cancer to either yourself or your family! No please grow some balls and make him do it right for you and your familys health??!!!

You shouldn' have to accept that shoddy work even if he is a friend of a friend. If I were you I'd get it re laid and done correctly.

Mellor

Twinkle Toes wrote:

Ewan the radon barrier is a soap below finised floor level. Instead of taking the barrier over the top of the block at finished floor level he took it under it.

I just want to doublecheck something. Is the radon barrier underneath the slab, and contining through the wall at the same level. Or is there a small upstand on it (over a soap bar under FFL) as it makes a huge difference.

galwaydude18]Look your only option in my view and probably a lot of peoples as well is make him dig up the slab and get him to put it down correctly!

The slab doesn't need to be dug up. The barrier is under the slab and exiting the wall at the wrong point. The wall needs to be taken down and relaid with the barrier in the right place.

Extending the barrier up and out with a bitumenous coumpound is the easiest option, its cheaper but your not paying. If you are doing this extend it out to the outer leaf but make sure itis also extended up the wall as this upstand is required to keep water from crossing it.

Twinkle Toes

Radon Barrier is underneath FFL and continuing at the same level

De_man

My builder has put down radon barrier firstly instead of taking radon over the the floor edge block he took it under it. This was bad enough but when I went home yesterday he had trimed all around the edge of the inner leaf so it dosn't reach the outer leaf of the footings as a result there is no DPC. My Engineer said this could only be rectified by torching felt on? Does anyone know a better way or have they done this before?

i have seen this done on one occasion on a "raft" foundation
i thought it was a better job running the barrier straight through
rather than the under and over method


This was bad enough but when I went home yesterday he had trimed all around the edge of the inner leaf so it dosn't reach the outer leaf of the footings as a result there is no DPC.

absolute madness!! are you absolutely sure that he didn't cross the cavity?? i find it hard to believe that a builder would do that....
well on second thoughts nothing surprises me:eek:

he would be putting in a separate DPC

Mellor wrote:

Extending the barrier up and out with a bitumenous coumpound is the easiest option, its cheaper but your not paying. If you are doing this extend it out to the outer leaf but make sure itis also extended up the wall as this upstand is required to keep water from crossing it.

mellor is correct, you could also try the following...cut lengths of radon barrier say 3ft widths the using "double sided tape" join to the existing barrier.

It's difficult to get right and Very Very time consuming but it should be okay provided the radon barrier is dry and dust free

Personally, i'd demand that the extra radon barrier required be "welded"!!!

Pity we don't have a photograph, how about uploading one?

what does your engineer say?

Shouldn't he/she have inspected the site before the slab was poured??

twenty8

To be honest it is not going to make much difference if it is there. The majority of radon barriers are not installed correctly. It is actually extremely difficult to install radon barriers and the majority of barriers that are put in are not put in properly.

I advise you to make sure that you put in radon detectors as soon as you move in. Everyone should do this regardless whether a radon barrier is in or not. If you have a high level of radon then you can use the sump to remove the gas.

If you want some further information just PM me.

smashey

twenty8 wrote:

To be honest it is not going to make much difference if it is there. The majority of radon barriers are not installed correctly. It is actually extremely difficult to install radon barriers and the majority of barriers that are put in are not put in properly.

I advise you to make sure that you put in radon detectors as soon as you move in. Everyone should do this regardless whether a radon barrier is in or not. If you have a high level of radon then you can use the sump to remove the gas.

If you want some further information just PM me.

Right. On what basis do you make your claims about incorrectly installed radon barriers?

Mellor

there is no reason that they can't be installed correctly, but I would imagine that certain areas are neglected, such as where services break the barrier, the barrier isn't resealed.

twenty8 wrote:

To be honest it is not going to make much difference if it is there

But I wouldn't agree fully with the above comment as it appears to forget that randon barriers also serve as damp proof membranes. and the floor external wall junction is the most critical in terms of water proofing.

I installed the radon barrier (the expensive reinforced stuff) in my place as recommended, plus three radon sumps, so far so good. Then 200mm EPS insulation, a layer of DPM then A192 mesh, UFH pipes were attached to the mesh.

Then got the screeders in, they went around all the internal (perimeter) walls marking levels (I'd already done this, but anyway) then they nailed a dozen rods through the dpm into the insulation & barrier to mark the ffl in the house, rather than using freestanding height markers. :mad:

I had two choices,

1. rip everthing up and patch the radon barrier & re install insulation UFH etc.
2. do nothing

I checked the rpi site and the area was <1% , am installing an active ventillation system, did a guestimate that the total size of the hole made is in the region of 200mm2 over a floor area of 180m2 also the subfloor is well drained (no capillary action through the holes).

I chose option 2, on the grounds that the increase in risk was probably too small to worry about. If the site had been in a high risk area then I would have been forced to do option 1!.

Not happy about it, but have to be practical

edit: I dread to think what builders get away with if this is the "standard" way to screed large floor areas!!

Mellor

Deleted User wrote:

I installed the radon barrier (the expensive reinforced stuff) in my place as recommended, plus three radon sumps, so far so good. Then 200mm EPS insulation, a layer of DPM then A192 mesh, UFH pipes were attached to the mesh.

Are the sumps actively being used, ie with a fan attached to the pipe, if so then it should be fine. Also your calculation on the hole size is exagarated. Each rod would of made a tear as opposed to a hole the size of the rod itself. If it helps your peace of mind.This like that do happen the whole time, especially at service entry and exit through floor.
Also a DPM above the radon barrier is a little overkill as the RB is gastight, this also means watertight. these small holes wont have a massive effect. And it isn't remotely as bad as the situation the OP was/is stuck in.

Mellor

Mellor wrote:

Are the sumps actively being used, ie with a fan attached to the pipe, if so then it should be fine.
No just going to a vent on the exterior wall, but unless testing shows an unacceptable level I'll just leave it as is.

Also your calculation on the hole size is exagarated. Each rod would of made a tear as opposed to a hole the size of the rod itself. If it helps your peace of mind.This like that do happen the whole time, especially at service entry and exit through floor.

Thanks, doesn't sound so bad now.

Also a DPM above the radon barrier is a little overkill as the RB is gastight, this also means watertight. these small holes wont have a massive effect.

I was keeping my options open on free-flowing screeds, the floor must be sealed otherwise the screed would flow under & lift the insulation. didn't use it in the end!

And it isn't remotely as bad as the situation the OP was/is stuck in.

Hopefully The OP can get it resolved without too much hassle!

tattoo

On the subject of radon barriers, every one i've spoken to says the rb should be orange but i've just bought one which is black. I'm also unsure of how to lay it properly i.e which tape to use.

all info would be much appreciated

muffler

tattoo wrote:

On the subject of radon barriers, every one i've spoken to says the rb should be orange but i've just bought one which is black. I'm also unsure of how to lay it properly i.e which tape to use.

all info would be much appreciated

I'd suggest you get someone who specialises in that area.

Twinkle Toes

Thanks for all the advice on this. Engineer came on Friday and suggested that top block be taken off all around the foundation and double sided radon tape used to attach another strip of radon so it will go over the top block at FFL and will also bridge the cavity correctly. He also confirmed that the radon barrier will work correctly now. I confirmed this with a radon intillation company who said they had rectified a similar error by doing this. The builder has agreed to do this work at his cost.

Mellor

Glad to see you sorted, make sure that when it goes over the block it goes back down and straight out and a separate DPC is installed in th external leaf.