Green Building Forum - What is the best proven method of fixing and finishing 200mm EPS EWI?

What is the best proven method of fixing and finishing 200mm EPS EWI?

docmartin — Wed, 02 Feb 2011 14:10:58 +0000

Several members have stated "put 200mm EPS on it", or words to that effect, on various threads.
6 days ago Fred56 reported that he "did not find anyone offering 200mm of insulation" ( on the single block ACC block thread).
Previously, another member has posted that a contractor simply refused to tender for 200mm EPS EWI; I can't find the post now.
My sole experience, so far, was researching the method and getting the materials for the plasterer doing my refurb to fix 25m2 of 60mmK5 EWB ( phenolic ) on a dense brick solid 9" wall of a single storey offshot kitchen.
This involved an adhesive mortar levelling coat, K5 boards mechanically fixed with nylon hammer-in fixings, cementitious base coat incorporating nylon mesh and a final JUB acrylic trowel-on finish. Although expensive the results have been so impressive that the plasterer has undertaken several more jobs using the method that I 'taught' him. I will certainly use EWI on a new build that I am currently researching.
However, the mechanical integrity of the bond of 200mm EPS to blockwork and the durability of the finish causes me concern. Is mechanical fixing, as well as adhesive, used at these depths?
The location is sheltered.

What is the best proven method of fixing and finishing 200mm EPS EWI?

docmartin — Wed, 02 Feb 2011 14:12:36 +0000

Edited

What is the best proven method of fixing and finishing 200mm EPS EWI?

tony — Wed, 02 Feb 2011 14:22:26 +0000

Almost routinely in much of central Europe, not even sure that they bother with foam just mechanical fixings?

What is the best proven method of fixing and finishing 200mm EPS EWI?

Mike George — Wed, 02 Feb 2011 16:41:47 +0000

Doc Martin has a good point though. Im not sure 200mm is manufactured in the UK. When Ive investigated in the past, ive been advised that I could use 2 x100mm slabs. I also have concerns over fixings, which I have not seen this lenght.

Same issue internally, and for this reason I have only used 62mm laminated plasterboards.

What is the best proven method of fixing and finishing 200mm EPS EWI?

Mike George — Wed, 02 Feb 2011 16:55:01 +0000

http://www.wbs-ltd.co.uk/images/pdfs/certificates/Epsitec%2009-4625_PS1.pdf

Covers fixing up to 60mm Phenolic

What is the best proven method of fixing and finishing 200mm EPS EWI?

fostertom — Wed, 02 Feb 2011 17:37:37 +0000

Current project using 200 EPS (not Platinum). Ribbon of adhesive 50 clear inboard of perimeter of ea 1200 x 600 board, plus dabs on 'interior' of board; 5 hammer-in fixings per board.

At this thickness, even the slightest un-flatness of the background causes significant tapered voids between board edges, so extensive squirty-foaming of joints is necessary - essential that those joints don't remain void, otherwise convection will bypass heat straight from warm to cold side. By the same token, essential that on pressing boards back onto the adhesive, no adhesive gets into said joints, otherwise the joints become conductive.

It won't end flat and flush, so much rasping of the surface reqd before rendering.

What is the best proven method of fixing and finishing 200mm EPS EWI?

MarkBennett — Wed, 02 Feb 2011 17:55:16 +0000

I approached 3 or 4 EWI/render system suppliers (including some of the big names like Weber and Wetherby) a year or so back and none of them had any problem doing with 200mm phenolic as EWI. I need to go back and look at the details, but I think most of them specified 2 layers of material. I think some used mechanical fixings and some used "glue".

If you look at the AI PassivHaus/Underhill House, then they used something like 300mm of EPS just glued on. According to http://www.sto.co.uk/99760_EN-Company-sto_passivhaus.pdf they can support up to 400mm of EPS.

Technically it is possible. Cost is another factor of course.

What is the best proven method of fixing and finishing 200mm EPS EWI?

jamesingram — Wed, 02 Feb 2011 18:00:14 +0000

Not sure of the best proven, but here's what I've used in the past and will be using on current project
http://www.netweber.co.uk/external-wall-insulation-systems/weber-systems/systems/webertherm-xm.html
xm system which uses EPS up 200mm

Bond insulation (1200/600) on to slab with adhesive , at least 50% coverage , then use 2 fixings per board/part board , I like this as it should reduce thermal bridging caused by the fixings ( compared to the 5/board systems)
then 3mm render on to EPS , trowel in mesh cloth , apply 3mm topcoat render , then prime, apply finish.

Detail as Tom suggests is important.

On the current project I'm sourcing my own super plus EPS ( lambda 0.030) from UK manifacturer via insulation wholesaler (special order,cut to 1200/600 ,which I will age myself on site)
as Weber dont use it , perhap for the reasons Tom suggested in another thread ( marginal U value improvement verses cost ??) and using a collection of left over materials from other projects

all there systems are described in this book
http://www.netweber.co.uk/external-wall-insulation-systems/find-the-right-solution/gb-external-wall-insulation-for-refurbishment-download-brochure.html
XM is a EST approved EWI system
http://www.netweber.co.uk/external-wall-insulation-systems/news-list/news.html?tx_ttnews%5Btt_news%5D=61&tx_ttnews%5BbackPid%5D=82&cHash=c4749d5180

just to say there are lots of other system out there and NBT woodfibre EWI with lime render I presume would be the most environmentally sensitive for choice of materials used.

cheers Jim

What is the best proven method of fixing and finishing 200mm EPS EWI?

docmartin — Wed, 02 Feb 2011 22:52:29 +0000

Jim,
thank you for the precise info about a system you have used successfully. Broadly similar to the JUB system I used with 60mm phenolic to achieve a U value of 0.28. Drilling for the 90mm nylon fixings was a problem on a proportion of the fixings when the drill deflected into the lime mortar course instead of the 1930's hard red brick. The prospect of this 200mm deep on concrete blocks was a concern. The aerated concrete blocks you are using do appeal for this reason; ordinary drill bits should even be possible.
Do you think that Tony's concerns about cracking and movement apply more to the 100mm aerated blocks rather than the 215mm? Regards, Martin.

What is the best proven method of fixing and finishing 200mm EPS EWI?

jamesingram — Thu, 03 Feb 2011 08:59:02 +0000

I think some people dislike any light weight block due to longterm stuctural/thermal movement concerns and poor plaster key, though a 215 got to be more solid than anything thinner.
I'm using a 140mm Fibrolite which I presume is somewhere in between a AAC aerated and medium dense block , mainly choosen for availablitly and ease of working with.( they had a few at my local builder merchant and I got a good deal ) I'd have preferred a medium recycled agg. block

What is the best proven method of fixing and finishing 200mm EPS EWI?

tony — Thu, 03 Feb 2011 09:21:49 +0000

me too

What is the best proven method of fixing and finishing 200mm EPS EWI?

Mike George — Thu, 03 Feb 2011 09:52:13 +0000

yep, and me

What is the best proven method of fixing and finishing 200mm EPS EWI?

fostertom — Thu, 03 Feb 2011 10:07:43 +0000

Posted By: MarkBennettmost of them specified 2 layers of material

That is surprising, as it's far more work than a single 200 thickness.

Posted By: MarkBennettsome used mechanical fixings and some used "glue"

that is also surprising, that there's such variation is 'best practice' still, after many years' experience.

Posted By: MarkBennettPassivHaus/Underhill House ... used something like 300mm of EPS just glued on. According to http://www.sto.co.uk/99760_EN-Company-sto_passivhaus.pdf they can support up to 400mm of EPS.

That's incredible. I mean, I assumed it would be all-glued to start with, but was then had impressed upon me the importance of mech fixings because of the considerable (?) outboard weight of thick EPS + render, as well as holding in place while the glue sets. How can there be such disagreement?

Posted By: jamesingramuse 2 fixings per board/part board , I like this as it should reduce thermal bridging caused by the fixings ( compared to the 5/board systems)

Too right, but again, how can they so disagree? Another variant (the excellent Chris Hirst http://thinjoint.com/)is to put one mech fixing at each board corner, on the joint line, so it straddles 3 boards.

What is the best proven method of fixing and finishing 200mm EPS EWI?

jamesingram — Thu, 03 Feb 2011 10:19:52 +0000

Tom , I presume no. of fixing depends on amount of adhesive used .
Weber XP one coat through colour system shows no board adhesive and 5 fixings in example video.

Re. glue for fixng together EPS / XPS anyone got a link to a supplier/make , as I'm struggling

the XPS I got for below DPC was only 100mm thick sheets , so I would prefer to glue them together before fixing.
Tried PUR glue ( gorilla grip) but it expanded a tiny amount and left small gaps

What is the best proven method of fixing and finishing 200mm EPS EWI?

davidfreeborough — Thu, 03 Feb 2011 10:55:43 +0000

Illbruck CT375 contact adhesive is specifically designed for bonding polystyrene:

http://www.tremco-illbruck.co.uk/products/02947_index.html

I don't know if they have EWI fixings, but EJOT are often recommended for warm roof fixings:

http://www.ejot.co.uk

David

What is the best proven method of fixing and finishing 200mm EPS EWI?

jamesingram — Thu, 03 Feb 2011 10:57:35 +0000

thanks David

What is the best proven method of fixing and finishing 200mm EPS EWI?

jamesingram — Thu, 03 Feb 2011 17:24:30 +0000

Re. Fixings for 200mm EWI , just ordered these up from Fischer ,
http://www.fischer.co.uk/PortalData/18/Resources/fixing_systems/salesinformation/_documents/10insulation/07.pdf
Unfortunatley the full range (on the german site) is only available to larger EWI supplier
http://apps.fischer.de/poc/default.aspx?page=layer&sprache=en&kat=$MART-HK-$MKAT-HK-$MPG-WDVS&ekat=$EKAT-HK-EN&path=$MART-HK-$MKAT-HK&path=$MART-HK-$MKAT-HK-$MPG-WDVS

What is the best proven method of fixing and finishing 200mm EPS EWI?

TimSmall — Wed, 13 Jun 2012 14:29:38 +0100

Posted By: jamesingram
On the current project I'm sourcing my own super plus EPS ( lambda 0.030) from UK manifacturer via insulation wholesaler (special order,cut to 1200/600 ,which I will age myself on site) as Weber dont use it

Sorry to dig up an old thread, but... The EPS supplier which I've been speaking to said that the EPS needs to be aged (for "three times as long" he said) during the manufacturing process, and that would seem to agree with page 2 of:

http://www.thermalinstallations.com.au/imagesDB/wysiwyg/TDS_Expanded_Polystyrene.pdf

... i.e. before the beads are fused together.

I presume you were told that aging on-site was sufficient? If-so, how long did you age it for, and under what conditions?

Is this the graphite-enhanced "platinum" EPS? If-so, then my understanding is that they do now supply it.

What is the best proven method of fixing and finishing 200mm EPS EWI?

TimSmall — Wed, 13 Jun 2012 14:30:26 +0100

http://www.thermalinstallations.com.au/imagesDB/wysiwyg/TDS_Expanded_Polystyrene.pdf

What is the best proven method of fixing and finishing 200mm EPS EWI?

jamesingram — Wed, 13 Jun 2012 20:13:42 +0100

"for "three times as long" he said" as what ?
Discussing shrinkage of EWI here http://www.aecb.net/forum/index.php/topic,3612.0.html
Tech guy from kay metzeler said "'most customers ask for it to be 'aged' 2-3 weeks in block form"
possibly a more informative post " A few years ago at an AECB Conference Berthold Kaufmann from the Passivhaus Institute noted that EPS can shrink by about 10-20mm per meter within the first 30-60 days. Like John he suggests a maturation period before installing on site."

Personally In the above case I brought straight off manifacturing run and aged onsite for 2+months as I had the time and space .
Yes platinum /graphite EPS

What is the best proven method of fixing and finishing 200mm EPS EWI?

jamesingram — Wed, 13 Jun 2012 20:19:37 +0100

I left some EPS installed on the wall, unrendered on one job for a couple of months, the boards exposed to the sun shrunk (after aged ) approx 5mm , though in shade didn't. Whether this would happen underneath when covered by render I'm unsure.

What is the best proven method of fixing and finishing 200mm EPS EWI?

TimSmall — Thu, 14 Jun 2012 11:24:33 +0100

Posted By: jamesingram"for "three times as long" he said" as what ?
Discussing shrinkage of EWI here http://www.aecb.net/forum/index.php/topic,3612.0.html

Sorry, I wasn't clear on this. He was saying that they allow the beads three times longer in the "aging" stage - this is carried out on the polysyrene beads before they get fused into blocks. From that Australian article on EPS manufacture:

"Aging
After pre-expansion the prefoam is transferred via to fluidized drying bed to large silos for aging. This process
is designed to allow for the replacement of expanding agent by air in the cells of the bead. Aging also allows
for stabilization and cooling of the prefoam."

... this was compared to the manufacturer's "standard" grade - which is typically used for applications such as underfloor insulation.

Thanks for the info!

What is the best proven method of fixing and finishing 200mm EPS EWI?

fostertom — Thu, 14 Jun 2012 15:12:36 +0100

Posted By: TimSmallreplacement of expanding agent by air in the cells

What is the expanding agent in EPS, BTW?

What is the best proven method of fixing and finishing 200mm EPS EWI?

jamesingram — Thu, 14 Jun 2012 15:31:22 +0100

pentane

What is the best proven method of fixing and finishing 200mm EPS EWI?

fostertom — Thu, 14 Jun 2012 17:03:21 +0100

Is that OK stuff?

What is the best proven method of fixing and finishing 200mm EPS EWI?

jamesingram — Thu, 14 Jun 2012 20:44:49 +0100

Seems ok ish
Scottish environment ad. factsheet
http://apps.sepa.org.uk/spripa/Pages/SubstanceInformation.aspx?pid=79
DOW Product Safety Assessment Pentane
http://msdssearch.dow.com/PublishedLiteratureDOWCOM/dh_0082/0901b8038008211a.pdf?filepath=productsafety/pdfs/noreg/233-00293.pdf&fromPage=GetDoc

What is the best proven method of fixing and finishing 200mm EPS EWI?

TimSmall — Thu, 14 Jun 2012 21:05:11 +0100

GWP is 5ish (it photo-degrades by combining with O2 to form CO2 + H2O I believe). I'm not sure what % of the pentane outgases during manufacture, and what % evaporates later. I get the impression that some of the more advanced EPS manufacturing plants capture the pentane for re-use.