new concrete floor, which insulation?

[alexander1982]

Hi Guys,
I am renovating my 1890s town house and as part of this I have removed the old wooden floors on groundfloor and am currently replacing with solid floors. As per my plans I have excavated down to depth. Put in 150mm hard core, 50mm sand and damp membrane then 150mm conctrete with a142 mesh midway. This is how it sits at the moment. My next plan is 100mm insulation. Underfloor heating clipped to this then finnished with a 65mm screed.
I have been looking at internet, books and speaking to trades counters ect and cant decide on which insulation to install. On the net 100mm is very expensive. I have 2 rooms of 36m square each to do.
Could someone advise on how to read energy ratings? Does it need to be celetex/kingspan? or does the polystyrene on the ebay do the same job? also would I be better going for 70mm say and more screed or would that be too much screed (80mm) and cost more anyway.
Any advise much apprciated.
Sorry about speeling.

 

[mointainwalker]

You cannot clip direct to expanded -polystyrene, the clips will tear out. If you want to use EPS, then lay down panels of welded-mesh ( 3 mm ) on top and wire to those.

Does it need to be celetex/kingspan? or does the polystyrene on the ebay do the same job?

It does the same job but not as efficiently. When new, Celotex insulates 60% better than EPS but over the years ( 7 or so ) this decreases as the celotex loses the gas in the cells which initially gives it improved properties. For this reason and taking the huge cost difference into account, I feel EPS is a better product as viewed from a cost/benefit standpoint.

Building Regs only look at the quoted values of the product ( as new ) and so what you can use may be limited by available height.

 

[freddiemercurystwin]

When new, Celotex insulates 60% better than EPS but over the years ( 7 or so ) this decreases as the celotex loses the gas in the cells which initially gives it improved properties. For this reason and taking the huge cost difference into account, I feel EPS is a better product as viewed from a cost/benefit standpoint.

Although mointainwalker has failed to point out out that there has been just as much negativity written about insulation types other than Celotex and the like over the years.

 

[mointainwalker]

FMT

If I have failed to point something out, it is because I am not aware of it.

What negatives are there about EPS in this application ?

 

[freddiemercurystwin]

I'm still waiting for a recent reference from you that this problem still exists.

 

[mointainwalker]

http://en.wikipedia.org/wiki/R-value_(insulation)

Insulation aging

Some types of foam insulation, such as polyurethane and polyisocyanurate are blown with heavy gases such as chlorofluorocarbons (CFC) or hydrochlorofluorocarbons (HFCs). However, over time a small amount of these gases diffuse out of the foam and are replaced by air, thus reducing the effective R-value of the product.

and also

http://www.marmox.co.uk/uploads/product_images/47/MarmoxProductBrochureOct09.pdf see bottom of page 2

Thermal conductivity 0.027 watts/mK

Thermal conductivity after 5 years 0.032 watts/mK

So they reckon that their board loses almost 20 % over 5 years which is a fairly significant whack and as far a I have read, this continues until it* ends up at the same value as expanded polystyrene and fibre-wool. ( *talking about closed-cell boards generally, not specifically Marmox )

So now what have you to say about EPS ?

 

[freddiemercurystwin]

I ignore anything written on Wikipedia and your Marmox reference is at least 2 years out of date and in anycase Marmox is extruded polystyrene not PIR.

 

[mointainwalker]

I ignore anything written on Wikipedia

Oh, hoity-toity !

your Marmox reference is at least 2 years out of date

I've no idea how old it is, but tell me why it is out of date.

in anycase Marmox is extruded polystyrene not PIR

Irrelevant. The important fact is that is a closed-cell foam like PIR and suffers the same problems.

So apart from replying to this, how about now answering about weaknesses of EPS ?

 

[freddiemercurystwin]

I can't be a bothered to trawl the web for an evening to prove my point, I have looked previously in the past and have found evidence that all types of insulation has bad press.

Your Marmot reference is at least 2 years out of date, the clue is written in the PDF link.

As mentioned it does not refer to PIR type insulation.

 

[mointainwalker]

Freddy, your replies to many queries are often good, but now and agaim you veer off.

I can't be a bothered to trawl the web for an evening to prove my point

Oh wow. You can ask me for proof of what I say, which I attempt to provide and then you come back with that. I'd have to say that's pretty bloody arrogant.

Pretty much like " You little people can do these things, but don't bother ME with it .."

Your Marmot reference is at least 2 years out of date, the clue is written in the PDF link

The link shows that it is two years old, but that does not mean at all that it is out of date by a day. It is not out of date until it is superseded. Are your Planning Regs out of date just because they are suffixed 2006. No, of course not . They are not out-of-date until replaced/proved wrong. Quit the pointless, pathetic quibling.

Regrettably i feel that you are dancining around, trying cheap shots to blur the issue like a dodgy politician in a TV interview.

You have now had a lot of reply from me, so how about replying ( in detail please ) to this AND finally coming across with details about the little known problems of EPS.

 

[freddiemercurystwin]

That's all I got, you got me and we both know it!

 

[alexander1982]

Didn't realise such debate went on on here. As it happens I got offered a load of 125mm kingspan through a friend whos company over-ordered.