16 February 2009 at 10:51 am #31065
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_1028 February 2009 at 4:21 pm #35803
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.
Mark28 February 2009 at 5:54 pm #35804AnonymousGuest
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.28 February 2009 at 6:49 pm #35805
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).
Mark2 March 2009 at 3:33 pm #35806AnonymousGuest
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.
Doug4 March 2009 at 6:48 am #35807
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?).
Nick5 March 2009 at 7:08 am #35808
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.6 March 2009 at 1:37 pm #35809
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.
* 15% of what? U-value unknown at this time! (I'm trying to find out)6 March 2009 at 3:42 pm #35810
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.
Nick6 March 2009 at 7:34 pm #35811
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.9 March 2009 at 1:02 pm #35812
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.
Mark27 March 2009 at 8:58 am #35813
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.30 September 2009 at 12:31 pm #35814AnonymousInactive
Did we get to some kind of consensus opinion on this? Just been to see a new build in Kent, the insulation will be warmcel but the owner/designer says she'd have used Icynene LDR50 if she'd found out about it earlier. Castor oil and water…1 October 2009 at 7:49 am #35815AnonymousInactive
I guess you are referring to Carol’s house. I am building a PassivHaus which I designed using the PHPP and which I hope to have certified. I have been trying to decide between Warmcel and Icynene for some time, both having advantages and disadvantages. I am now leaning towards using Icynene LDR50 even though it is slightly more expensive. I hope to produce a diary of the build, detailing construction methods.1 October 2009 at 9:55 am #35816AnonymousInactive
Yup it is Carol's house, very nice I thought.
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