protecting radon barrier

self_builder

Hi all,

Doing subfloor at the minute in self build. Is it normal to leave radon barrier exposed during build or should you pour concrete over to protect it? Add far as I can tell it is done differently throughout the country. Was hoping to only pour concrete for screed i.e. hardcore, sand blinding, radon, 150mm platinum aerobord, then underfloor pipes & screed ?70mm. Any advice? Thanks

sydthebeat

self_builder wrote: »

Hi all,

Doing subfloor at the minute in self build. Is it normal to leave radon barrier exposed during build or should you pour concrete over to protect it? Add far as I can tell it is done differently throughout the country. Was hoping to only pour concrete for screed i.e. hardcore, sand blinding, radon, 150mm platinum aerobord, then underfloor pipes & screed ?70mm. Any advice? Thanks

you cannot just pour a 70mm screed, you need structural sub floor...

holy god says miley

self_builder

AFAIK and I am no expert if it was 150mm pour of concrete would this be ok. But I wasnt sure about having the underfloor pipes in this much concrete??

Hitchens

If I was you I would try and avoid putting water pipes under concrete. Have every piece of plumbing easily accessible at all times and you will have no headaches in years to come (that's if this house is going to be your home for a long number of years).

sydthebeat

self_builder wrote: »

AFAIK and I am no expert if it was 150mm pour of concrete would this be ok. But I wasnt sure about having the underfloor pipes in this much concrete??

if you are not, then who is advising you?

im not trying to be smart here, but your first post shows very fundamental errors. For your own sake, i hope you are going to get a professional to design the construction for you.

self_builder

Yes this will be our home and I am only planning on doing this once! What would you put the pipes in so?

Syd - yes it has been designed by architect and engineer. The plans contain however generic heating (oil and rads) and insulation (Kingspan, Kingspan, Kingspan) spec so changes are up to ourselves. They were draw a few years ago also. I know it sounds dubious, if I was starting again I would spend a lot more on our architect. The spec i listed is one i got from heating company except with 150mm concrete. What errors do you see? Would appreciate your advice.

sydthebeat

i personally wouldnt put UFH pipes into anything more than 75mm screed.

however you MUST have a concrete subfloor for basic structural integrity. So you need two pours!!

From what youve posted it sounds like you have no current professional imput, only what was designed for planning?? am i correct?

self_builder

Architect is supervising build and professional builder on site

sydthebeat

self_builder wrote: »

Architect is supervising build and professional builder on site

"supervising" or "inspecting" ??? theres a huge difference?

what does your architect suggest regarding this detail, as s/he will be the one 'signing it off'.


oh and last question, is it a raft foundation? because that will determine the detail as well.

self_builder

Thanks Syd. Architect is inspecting site. Its a standard foundation not raft. I did ask architect and he said he has seen it done before and he was happy but did not supply drawings. I have heard that it is done this way in certain parts of the country??

sydthebeat

self_builder wrote: »

Thanks Syd. Architect is inspecting site. Its a standard foundation not raft. I did ask architect and he said he has seen it done before and he was happy but did not supply drawings. I have heard that it is done this way in certain parts of the country??

:eek::eek::eek::eek:

happy with a 70mm screed and no subfloor????

alarm bells ringing here.

self_builder

Thanks Syd, Ill go back to drawing board and look into it more

fclauson

also - how are you complying with part L

if plans where drawn up a couple of years ago then this was probably to part L 2008 - we are now using part L 2011

I would go into maniacal detail now before you do anything more

What are the U values of all of your structures ?

self_builder

Thanks fclauson, yes we are aware of Part L - will be using air to water and solar.

U-values: floors - 150mm platinum aeroboard = 0.15 + perimeter insulation, 200mm pumped cavity = 0.15, 300mm sheepswool/rockwool on flat ceiling= 0.13, sloped ceilings and dormers we are trying to decide on at present and will be the trickiest detail for us (U-values not taking into account of cold-bridging). Triple glazed windows = 0.7/0.8 - haven't decided on which company to go with yet.

We unfortunately need to press ahead with the build so yes we are aware we will have things we would have changed but we are trying to do as much research at present - not ideal I know. Have got provisional BER done and hope to achieve A3 but DEAP/PHPP calculations don't fit into our budget.

muffler

self_builder wrote: »

Have got provisional BER done and hope to achieve A3 but DEAP/PHPP calculations don't fit into our budget.

Hope is a naughty word. Change it to "will have to"

Hitchens

self_builder wrote: »

Yes this will be our home and I am only planning on doing this once! What would you put the pipes in so?

If your question is for me then here's what I would do:

1. I wouldn't use underfloor heating at all.

2. I would design a channel system in the floor perimeter to carry the pipe work.

hexosan

Hitchens wrote: »

If your question is for me then here's what I would do:

1. I wouldn't use underfloor heating at all.

2. I would design a channel system in the floor perimeter to carry the pipe work.

Why would you not use UFH

Hitchens

hexosan wrote: »

Why would you not use UFH

Just to say that this is my opinion, others may have a different one:

1. It takes too long to heat up from cold.

2. Any leaks in the future will be a nightmare (assuming a wet system here).

hexosan

Hitchens wrote: »

Just to say that this is my opinion, others may have a different one:

1. It takes too long to heat up from cold.

2. Any leaks in the future will be a nightmare (assuming a wet system here).

1. If the house is kept at a constant temp then you don't have an issue with heat up/ cool down.

2. I hear this point about leaks all the time with UFH, if your so worried about leaks, how do you get over the fact that your qualpex radiator pipes are also going to be buried in the ground and can potentially leak as well.

Hitchens

hexosan wrote: »

1. If the house is kept at a constant temp then you don't have an issue with heat up/ cool down.

2. I hear this point about leaks all the time with UFH, if your so worried about leaks, how do you get over the fact that your qualpex radiator pipes are also going to be buried in the ground and can potentially leak as well.

1. Maintaining a constant temp means having the boiler constantly cycling, which may not suit people who are a bit strapped for cash.

2. My qualpex pipes will not be buried, that's one of the points I first made.

(but as I said, this is just my way, it may not be the popular way)

sydthebeat

Hitchens wrote: »

1. Maintaining a constant temp means having the boiler constantly cycling, which may not suit people who are a bit strapped for cash.

2. My qualpex pipes will not be buried, that's one of the points I first made.

(but as I said, this is just my way, it may not be the popular way)

1. A cycling boiler is a result of a badly designed control system.
Current regs pretty much denies having this. see 'boiler interlock'

2. if an ufh system should leak, then there is specific machinery to find and fix such leaks, its not a huge issue AT ALL.

delfagio

Hey Self Builder,

Basically this should be the kind of detail you need for the sub-structure;

1) Concrete Strip foundations (assuming thats what you have done) <SNIP>
2) Rising walls/dead blockwork brought up to the correct height for subfloor
3) Hardcore such as 3" or 4" down to bring your levels in the floors, up to correct height, make sure this is well compacted.
4) Approx 6inches of a layer of Cl.804 stone should be added on this to cover over the 3" or 4" down hardcore, as this makes it easier to walk on and cover for radon barrier, again make sure it is well compacted. Obviously radon sump/s and radon pipes laid to external walls to allow radon to escape. Don't forget to add in you upstand waste pipes for toilets, sinks, or ducting for heating pipes at this stage as well, save you having to dig floors up again later.
5) A sand blinding layer can then be added approx 50mm thick, this can be compacted also with a vibrating plate to give protection to the radon barrier from any sharp tones penetrating the radon barrier.
6) Radon barrier can then be laid and ensure to have good overlaps with radon tape sealant to prevent any radon gas getting through into the house. Pay close attention to this. Also better to use a reinforced radon barrier as it is a lot tougher than the non reinforced radon barriers. It is a good bit dearer but well worth it.
7) Once all radon barrier is taped and held down with blocks along edges etc, a concrete subfloor can be laid. This is generally <SNIP> A layer of mesh should be added into this concrete subfloor to prevent against cracking, sinking etc. Most building surveyors/engineers will say that there is not much need for this steel mesh, however it is best to add it in now, as it can't be done later on. Use <SNIP>
8) This is it for now, you can have your blocklayer start his block works for the walls, or timber frame company install their frame etc.

Once your blockwork/timber frame is complete, and roof on and weather tight and preferably after internal plastering has taking place, you can then layer 150mm - 200mm of rigid insulation onto your subfloor, ensure they are taped on joints, and as more than likely this insulation will be done in 2 layers, make sure you stager the joints. Don't forget to lay edge insulater upstands along the walls to prevent heat been transfered through the walls.

Then lay your plastic sheeting, on top of which you lay your underfloor heating pipes. You can now lay your screed on top of the pipes.

Instead of going with a <SNIP>, perhaps look at easi-screed, or self leveling liquid screed which is much better suited to underfloor heating, as it has a faster reaction time to the heat response. Plus it can be laid at thickness of <SNIP> and you will have better leveled floors, which will make any tiling or wooden floors easier to lay.

Hope this helps Self Builder,

Sorry for the long winded reply.

Anybody can correct me if i am wrong

Delfagio

Hitchens

sydthebeat wrote: »

1. A cycling boiler is a result of a badly designed control system.
Current regs pretty much denies having this. see 'boiler interlock'

2. if an ufh system should leak, then there is specific machinery to find and fix such leaks, its not a huge issue AT ALL.

1. by constantly cycling I mean the normal on/off cycle as per thermostat settings.

2. not if but when unfortunately, and in the case of fixing it ....it's like the cure being worse than the disease in monetary terms.

muffler

delfagio wrote: »

Anybody can correct me if i am wrong

I have just corrected your post. Please read our forum charter, particularly Section 1.5 before posting again and I hope there will be no repeat of specifying structural items here.

Stone Deaf 4evr

You need to go buy the homebond house building manual. Full of priceless information and details that comply with the building regs.

sydthebeat

Hitchens wrote: »

1. by constantly cycling I mean the normal on/off cycle as per thermostat settings.

2. not if but when unfortunately, and in the case of fixing it ....it's like the cure being worse than the disease in monetary terms.

we are going slightly off topic here, but seeing as the OPs query has been all but answered....


1. All modern heating systems are should be set up so the thermostat controls when the boiler comes on or not. That's regardless of the fact whether its a rad system or UFH or whatever.
The whole theory of modern building is that we no longer should have heating up / cooling down periods. Modern building regulation levels are so onerous so as to limit heat loss through elements and air infiltration as much as possible. By retaining the heat within the build, that means your heat emitting systems are under less pressure and the need for a high responsive system is negated.
Plus, delayed start thermostats are a standard spec now because of their cost / benefit under DEAP analysis.

2. like i said previously, its not AT ALL a huge issue to fix a UFH leak. Once the system has been properly pressure tested and the loops identified and denoted then finding the leak is not difficult. More often than not its where some protrusion has been fitted recently.
To be honest, id rather have a UFH leak in a first floor than a rad leak.


anyway, the choice of UFH to rad is mostly more personal than practical.

laying your rad pipes in conduits on a ground floor is probably ioverkill, but so be it.

You cant lay UFH pipes in conduits.

Hitchens

sydthebeat wrote: »

anyway, the choice of UFH to rad is mostly more personal than practical.

laying your rad pipes in conduits on a ground floor is probably ioverkill, but so be it.

You cant lay UFH pipes in conduits.

Conduits? ...I never mentioned conduits, either with or without UFH, maybe we are confusing each other

sydthebeat

Hitchens wrote: »

Conduits? ...I never mentioned conduits, either with or without UFH, maybe we are confusing each other

apologies, when you referred to your qualpex pipes not being buried, what did you mean?

Hitchens

sydthebeat wrote: »

apologies, when you referred to your qualpex pipes not being buried, what did you mean?

no worries ....see (2.) #16

sydthebeat

i assume you wouldnt be insulating the pipes then?

Hitchens

sydthebeat wrote: »

i assume you wouldnt be insulating the pipes then?

I would indeed

sydthebeat

Hitchens wrote: »

I would indeed

do you think you can afford to reduce the perimeter of a floor slab by 65mm min ??

do you think that would be accepted by a certifying engineer / architect?

Hitchens

sydthebeat wrote: »

do you think you can afford to reduce the perimeter of a floor slab by 65mm min ??

I don't see why not

do you think that would be accepted by a certifying engineer / architect?

I don't know tbh, but when I did mine none of that was necessary.

(we had all those regulators during the boom and did it really mean much benefit to Johnny Raw?)

sydthebeat

Hitchens wrote: »

I don't see why not

I don't know tbh, but when I did mine none of that was necessary.

(we had all those regulators during the boom and did it really mean much benefit to Johnny Raw?)

well that says enough for me..... thank you and goodnight.