Icynene - alternative to Warmcel?

[fostertom]

What opinions of Icynene? - see my summary 15.2.09 in this http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3341&page=1#Item_10

[Mark Siddall]

Tom
You could call this "spray-in-place foam insulation"

Anyway.... Not convinced by spray-in-place foam insulation. This also goes by the name of Flash foam. I first heard of it being used in a PassivHaus being built in the USA and this led me make some enquiries. The key problems are:

1) For PH standards of airtigthness it is not "the" solution as it I have been told by an experienced builder in the US (that has constructed super inusulated homes for many years and now has started PassivHaus) it "does nothing to address the gaps between multiple studs and lintels over openings" i.e. still need standard airtight details using a continuous barrier.
2) The foam layer is usually built up in layers 12-25mm thick. It then has to be left to cure before the next layer is added. Does this save time?
3) If possible foam insulation should be used sparingly due to petrochemical content and high embodied energy. (Unlike Warmcell which is recycled news paper and has a low embodied energy.)
4) The USA has great deal of experience with these products. Much of it is bad.
For example in some installations shrinkage has split the foam all over the place and distorted framing members. Furthermore Michael LeBeau (my contact) notes that "cracks develop in foam several months after installation. If you stick a knife in year old foam it starts a crack that can open up for several feet and can be wide enough to get my hand in. Of course most of the time everything is covered up by the time this shrinkage occurs." That troubles both me and Michael.
5) As it is an American product does it comply with ZODP and does it have a GWP of less than 3? (I'd lost interest by this point so didn't check.)

So, an alternative to Warmcell? I think not.
Mark

[Doug McEvers]

Hello Mark,

Maybe some test walls are in order for the different new products available. Testing to see how they age and if the manufacturers claims are accurate for infiltration reduction properties and insulation value. Some of the open cell foams have been problematic in cold climates as they need a separate air/vapor barrier to keep the insulated cavity from excess moisture retention.
I am also concerned about shrinkage of some of the foam products, infrared scanning of some built housing using open cell foams may possibly show shrinkage gaps.

[Mark Siddall]

Hi Doug,
Yes, I agree, test samples would be a good way of learning about the pros and cons.

By the way. I understand that these spray foams got band for a while in the US. Then at some laterl date a number of states reviewed how to the foams could be used and some rigorous QA procedures were established (adding to the cost of instalation).

Mark

[Doug McEvers]

Mark,

I am by no means an expert on foam insulation but some of the early spray in place foams in the U.S. contained formaldehyde. I applaud the industry for seeking a more environmentally friendly foam product, time will tell if the water based foams are durable and cost effective.

Closed cell foams like spray polyurethane have been used with good results, the air sealing properties are good and the R-value is somewhere around 6.5 per inch. The concern with this family of products is the blowing agent used, HCFC's raise havoc on the atmosphere and we need to demand more environmentally friendly manufacturing processes.

Are spray foams durable and cost effective and does the long term benefit (increased efficiency) outweigh the short term global warming (HCFC,CFC)consequences? Acelerated testing would help with durability concerns for the water based foams, an honest scientific evaluation for the others, polyurethane, extruded polystyrene and the like is in order.

I have and still use some extruded polystyrene and polyurethane foam board products, in some detail areas, they work very well. I am trying to substitute with higher density expanded polystyrene where feasable.

Doug

[fostertom]

Up late waiting for the early bus to Ecobuild! At end, I've copied over what I summarised about Icynene on http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=3341&page=1#Item_10.

I have been told by an experienced builder in the US (that has constructed super inusulated homes for many years and now has started PassivHaus) it "does nothing to address the gaps between multiple studs and lintels over openings" i.e. still need standard airtight details using a continuous barrier.

Wouldn't same be true of blown-in Warmcel, which I'd hope would also have airtightness that could dispense with a continuous barrier? If Warmcel/Icynene can't penetrate such spaces, what hope for blanket or board insulation? Closed-off and narrow spaces can be designed out, not insist on bog-standard timber panel layout. More to the point, neither Icynene nor Warmcel can seal to window/door frames, nor usually to wet plaster as airtight membrane, so I'd reckon on an edge-strip of membrane there. Icynene not only puts itself into compression, like blown Warmcel, but also adheres to the studs/rafters or whatever it's jammed against.

The foam layer is usually built up in layers 12-25mm thick. It then has to be left to cure before the next layer is added

AFAIK Icynene is applied in one pass - will check.

If possible foam insulation should be used sparingly due to petrochemical content and high embodied energy. (Unlike Warmcell which is recycled news paper and has a low embodied energy.)

Since http://www.ukgbc.org/site/resources/showResourceDetails?id=63 I've held that such insulation is the best possible use for petrochemicals, if that use saves a zillion times more petrochemical as fuel during its lifetime. Icynene tell me it's "a type of polyurethane foam insulation.  The resin portion of the chemistry is a guarded secret".  Polyurethanes are likely to be made of soya instead, but I'm not sure that's a good thing! "water is included in the resin to provide a blowing agent for the foam.  There are no blowing agents" - "We have conducted VOC testing and I have attached a summary of the results along with the analysis conducted by the Toxicologist" - negligible.

in some installations shrinkage has split the foam all over the place and distorted framing members. Furthermore Michael LeBeau (my contact) notes that "cracks develop in foam several months after installation. If you stick a knife in year old foam it starts a crack that can open up for several feet and can be wide enough to get my hand in.

Icynene stays softly rubbery and stretchy forever apparently.

As it is an American product does it comply with ZODP and does it have a GWP of less than 3?

Icynene is Canadian FWIW. As it's water-blown I'd think it has ZODP and very low GWP but will check specifically.

"No blowing agents included in the material and as a result there is no long term thermal degradation of the insulation.  It is light weight and flexible and can move along with the structure during building movement.  The insulation does not crack or debond.  Air seal of the insulated cavity is thereby maintained."

Here's my summary:

"Looked into Icynene and it seems to be a good option.
Its virtue is as an alternative to blown-in or wet-sprayed cellulose e.g Warmcel, in that

Both force their way into any cavities or hidden spaces that might be difficult to fill with other insulations, and remain there in compression.

Consequently both make a good airtight job without all the palaver of installing a separate airtight membrane - but you still have to work out how it's sealed airtight to other adjoining elements, like wet plaster (as airtight membrane) and windows.

Both are very water vapour transparent, thus suitable for 'breathing wall' constructions,
and also providing a better route for structural water content seasonal ebb and flow, than all being concentrated into the rafters because the insulation between is impervious (e.g. Cellotex).

The only doubt remains its eco-credentials, that I'm still pushing for info on, so may yet fall at the last fence!

The new UK installer is http://www.airsealinsulation.co.uk. Only the Spray version available so far in UK - the alternative Pour Fill (poured into a cavity where it expands) to follow maybe.
Installed price (Devon) comparable to foil faced PUR for similar U-value but lower k so thicker.

Icynene Density: Spray 7kg/m3; Pour Fill denser (unverified).

Thermal resistivity k: Spray Icynene 0.039W/mK; Pour Fill Icynene about 0.035 (unverified). That's similar to basic EPS (expanded polystyrene - the white bead-board) or Warmcel.

Air permeability for 133thk: both Icynene types 0.0049 litre/s.m2 @75Pa. That's very airtight - 0.02 is a good air barrier)

Water vapour resistance G for 127thk: Spray Icynene 1.67MN.s/g; Pour Fill Icynene 3.9

Water vapour resistivity r: Spray Icynene 13.15MN.s/g.m; Pour fill Icynene 32.5. Dividing by 5 gives German-style µ (mu)-value Spray Icynene 2.63; Pour Fill Icynene 6.5 (the BBA Cert says 2 to 5). That's very low resistivity indeed - slightly more resistive than min fibre, same as the most open kind of wood fibre board.

Hygroscopicity (capacity to absorb and release water vapour (not liquid) from and to the air as the relative humidity of the air changes) - Icynene very low, unfortunately, like most mineral or plastic insulants. By contrast, Warmcel, like other plant/animal fibres e.g. sheeps wool, has high hygroscopicity, so acts as a humidity buffer if not isolated (by a vapour check) from the building interior. Warmcel etc can also act as a heat store, beyond its thermal capacity, by also absorbing/releasing the heat content (incl some latent heat) of the absorbed water vapour. That so far is the main deficiency of Icynene.

Note that water vapour permeability is different from hygroscopicity.
Water vapour permeability is about allowing water vapour to pass through, when there's a vapour pressure gradient.
Hygroscopicity is about 'hungrily' soaking up any water vapour into itself (though not liquid water - that's capillarity!).

Icynene though very airtight is very transparent to the through-passage of water vapour . It's confirmed that both of these factors hold whether or not any skin to the foam is removed or punctured.

Spray Icynene expands 1:100 in seconds; Pour Fill Icynene expands 1:60 in minutes. So both force their way into any cavities or hidden spaces that might be difficult to fill with other insulations.

Both Icynene types adhere strongly to surfaces - unless covered with loose muck, presumably. Blown-in Warmcel of course doesn't adhere.

Icynene has a soft rubbery spongey texture, apparently forever - so quite different from other rigid board- or spray-foams. This bodes well for continued airtightness.

It's possible that Icynene's not-brilliant k-value 0.039W/m.K is what other PU foams sink to once the blowing agent retained in the bubbles has eventually permeated out and been replaced with air. A little while back, all the foamed insulations - board, spray and squirty - had their quoted k-values downgraded, from as-new with full blowing-agent content, to something based on average content over lifetime, or similar. In other words, typical foam insulations start better than quoted but end worse than quoted. The foil facings on Cellotex are as much about retaining the blowing agent, as about reflectivity. Icynene is (possibly?) unique in that it uses water as blowing agent, so no beneficial blowing agent is retained in the bubbles, so k-value doesn't decline with time, on that score at least."

More comment appreciated.

[Nick Grant]

A lot of detail to wade through but I want to pick up on 'airtightness'. Tom, unless I am reading you wrong you seen to be suggesting the foam can act as an air barrier. Great to prevent convection etc in the insulation but not bulk air movement through the structure, would still need an air barrier and IMHO an external wind proof layer as well for good measure. Mark S will hopefully pick up on this as he is presenting an excellent paper on it at Frankfurt PH conference this year (and hopefully at the AECB Conference?).

Nick

[fostertom]

Thanks Nick that's v much to the point, a gap in my data that may now get filled - so what figure l/s.m2 would constitute a bulk-air barrier?

If inboard, are you suggesting an additional anti-wind outboard one, which ordinarily lapped  breather felt wouldn't provide? Is that just a IMHO, or would anyone enlightened agree? Is so, then we cd forget inboard airtightness incl wet plaster and just do outboard?

[Nick Grant]

Tom

Need inboard and outboard. Some people have just done one and either will give good blower door test.

lapped breather should be fine on outside but don't do what I did on our house and save £50 by running it horizontal rather than vertical with battens to trap the joins. Same with roof, Mike Whitfield showed some great slides on this at the Durham conference couple of years ago, think they are here:

http://www.aecb.net/conference2007.php

Re required air-tightness of material  I'd say 100%. Target <0.6 air changes @ 50 Pa, you can do the maths for the foam but also need to note that this is a hard target even with 100% airtight board, membrane or and or wet plaster since the leaks are normally thru the gaps and joins.

Did you spot the soya foam at EcoBuild?

Nick

[fostertom]

Running felt vertically trapped by battens - that's good,

80m2 house, say 400m3 and 300m2 external surface x 0.0049 litre/s.m2 @75Pa air permeability as quoted by Icynene > 5.3m3/h = 0.013 ac/h - at higher Pa! That seems near enough 100% airtight, so in-use performance would depend entirely on installation gaps, freedom from cracks etc longterm, connection to windows and other membrane types elsewhere. Just like a continuous membrane in fact!

Before we (I) dismiss Icynene (or Warmcel) as airtight barrier, on these figures Icynene looks v good. What do you think? I do like things that do the job inherently and robustly, without recourse to fragile membranes etc.

[Mark Siddall]

Tom,
What you need to find the airleakage at the untreated joints (this was you can guage the remedial work required.)

To limit heat losses incurred by air movement to less than 15%* Canadian research suggests that an Air Leakage of < 0.07 m3/(m2 h @ 75 Pa) is required for the barrier. Incuding the joints <0.72 m3/(m2 h @ 75 Pa. Also note that a PE air barrier has a non-measureable (as they say in Canada) air leakage i.e. 0.00 lt/s/m2 h @ 75 Pa. 8mm Plywood has 0.0067 lt/s/m2 @ 75 Pa so Icynene is not all that special.

Mark

* 15% of what? U-value unknown at this time! (I'm trying to find out)

[Nick Grant]

NB I have edited my post as when replying in haste I missed out a decimal point calculating leakage in m/h from l/sec. So yes foam quite airtight.

Nick

[fostertom]

Canadian research suggests that an Air Leakage of < 0.07 m3/(m2 h @ 75 Pa) is required for the barrier

Icynene claim 0.0049!

Incuding the joints <0.72 m3/(m2 h @ 75 Pa

That's the challenge! The question is, are tape joints of unknown longterm durability a better or worse prospect for continuity/joints, than in-depth integral airtightness of an expanding and adhesive mass material like Icynene (or Warmcel, without the benefit of adhesion).

8mm Plywood has 0.0067 lt/s/m2 @ 75 Pa so Icynene is not all that special.

but it is in the top rank!

I'm still open to decision either way - to me it looks finely balanced, and my worry about tape joints is considerable.

[Mark Siddall]

Tom,
PE and OSB are far more dimensionally stable and have fewer joints/m2 (can oversail rather than having to sit between studs). Also, though I'm aware of the Warmcell "plugs the gaps" arguement it should not be considered as an airtightness solution.

With the risk of the Icynene insulation shrinking you have not only airtightness issues but thermal bridging issues to contend with. Going back to point up all the joints seems labour intensive and expensive (by the way who mentioned tapes to remediate this? I reckon that you'd need low expansion foam). Finally as the material shrinks there is also the threat that convective loops could develop undermining performance.

This does not look finely balanced to me. Spray in place is chock with risk and uncertainty. In my view still an unwise solution.
Mark

[Nick Grant]

Mark Brinkley has started a discussion on his blog. More about U value claims although not clear if they are claiming magic properties as yet unexplained by science, as multifoils, or just that the foam achieves a reliable U value with no degradation due to air movement.

ie is the foam better than hot box suggests or are other insulations worse in reality.

http://markbrinkley.blogspot.com/2009/03/on-icynene.html