200mm EPS

Mike2006

Hi,

I plan on putting down 2 x 100mm Aerobord platinum EPS in my floor of a new build, on top of that the UFH piping and then on top of that 50mm screed.

Does anybody see any problem with using that depth of insulation?

Thanks,

Mike.

Poor Uncle Tom

Yes. It will be virtually impossible to get the insulation layers together without some movement/space/voids vertically and laterally between the sheets. 50mm is a very slim screed to have over this 'spongy' base. Reinforcement of the screed is going to be very important as is the laying/positioning of the insulation layers.

archtech

We had a case recently where a 150mm conc floor of small area was placed on top of 100mm insulation and the whole thing cracked , still can't figure out what caused it other than possibly putting it down to the thickness of insulation. So its case of reinforcement in future for any floor with 100mm insulation or more.

Personally I wouldn't use a screed of less than a target of 75mm thickness.

Mike2006

Uncle Tom, (feels weird tying that as I have an Uncle Tom!!)

what would you recommend either above or below??

I was looking at the 200mm of EPS as it has a u-value of 0.12.
I could go with a thicker screed but then the response time of the UFH decreases a lot too.

Could also achieve 0.12 with 140mm kingspan but have read too much about off gassing of that product so have decided to avoid....

So how do you achieve the low u-value and also have a 'correct' bed for the ufh pipes???

Mike.

sas

Mike2006 wrote: »

I was looking at the 200mm of EPS as it has a u-value of 0.12.

Mike.

The u-value of 200mm of platinum EPS is around 0.15, not 0.12. I know there is a table on their website saying this but it's wrong based on the IAB cert thermal conductivity of 0.031.

redonly

what is off gassing?

sas

redonly wrote: »

what is off gassing?

Insulation depends on trapped gas to provide insulation.

In the case of EPS (white or grey) this gas is normal air.

In the case of kingspan PUR the gas is pentane I believe. The concept of off gassing is where the gas slowly over time is released from the board. This is then replaced by regular air hence somewhat reducing it's insulation effect.

There is also a theory that any non natural insulation (i.e. EPS, Kingspan etc) gives off all sorts of nasty stuff into your breathing air over time. This I'm alot less convinced of.

Poor Uncle Tom

Mike2006 wrote: »

Uncle Tom, (feels weird tying that as I have an Uncle Tom!!)

what would you recommend either above or below??

I was looking at the 200mm of EPS as it has a u-value of 0.12.
I could go with a thicker screed but then the response time of the UFH decreases a lot too.

Could also achieve 0.12 with 140mm kingspan but have read too much about off gassing of that product so have decided to avoid....

So how do you achieve the low u-value and also have a 'correct' bed for the ufh pipes???

Mike.

I've been called much worse...:D

Imo, if you wish to use any substantial thickness (over 100mm) of insulation in the floor then I would construct a loadbearing timber/steel joist system, insulate between and/or below the joists and use the joists to support the screed and heating piping.

Mellor

sas wrote: »

In the case of kingspan PUR the gas is pentane I believe. The concept of off gassing is where the gas slowly over time is released from the board. This is then replaced by regular air hence somewhat reducing it's insulation effect.

hmm, i'm not completly sure on that one.
Pentane is the blowing agent used in manufacture, not the finished insulator. And it is slowly released once set. The minute they come off the line, the conductivity is much less than the published results. it stands to reason that the conductivity will stabilise once it reaches 90-100% pentane replacement.

I would hope that the value in the IAB cert was at almost 100% replacement. It should be anyway. I haven't read it throughly.

I have no idea what value is used by kingspan, and any other similar boards. They may or may not be misleading, I have however seen other rival companys tell misleading facts about the pentane to make KS look bad.

sas

Mellor wrote: »

hmm, i'm not completly sure on that one.

Neither am I. I should have underlined that it is a theory that is thrown around.

I was speaking recently to someone who was at a trade show in Germany. Kingspan were there as was a german manufacturer of a similar product. The germans were quoting a thermal conductivity 0.05 worse than kingspan. So there may be something in it.