pro's & cons of different ICF systems

[Jeremy Harris]

37 minutes ago, najem-icf said:

I doubt the risk of concrete burning off the foil is something that will happen in the short term - so I guess we will just have to "watch this space" - I have asked the a colleague who works in the Built Environment section of a University here to see if he can assist me with determining the longer term effects of this kind of scenario.  If nothing else, it is an interesting topic.[/quote]

As a former chemist, I can say with certainty that the majority of the reactions will have completed within around 2 to 5 days.  After that time, the only reactions taking place will be very, very slow ones, relating to changes deep within the structure of the concrete, that cause it to harden gradually over the next few decades.

 

Quote

 

Oh gosh - I strongly disagree with you here.  EPS with FRA has an ignition point of 360°C.  Prior to this EPS will melt at source but will not spread flame.  There are numerous tests that have been conducted that have confirmed this.  If the EPS perishes, you have a monolithic wall of concrete with no breaks in it to facilitate the spread of flame.  The foam products of yesteryear (mainly ceiling tiles in kitchens) have long since ceased existence.  All ICF EPS/XPS now use Polymeric Fire Retardants as it became illegal in North America to use HBCD.  As we know, North America is the worlds biggest ICF market.  EPS is 98% air.

 

PUR on the other hand is a known flammable product, decomposition from fire can produce significant amounts of carbon monoxide and hydrogen cyanide.(<- straight out of wikipedia!)  Grenfell is a prime example of what PUR/PIR insulation can do.  The internet is littered with examples of PUR/PIR fires.

 

 

I refer you to the Grenfell Tower thread here.  Read that, understand the research several of us have done, and then comment.

 

Better still. put a sheet of PIR/PUR foam on a non-flammable surface and point a blow torch at it.  Then do the same with a sheet of EPS/XPS and tell us what you discover by experiment.

 

I've extensive experience with using PUR foams in foam core aircraft structures (where certification requires fire resistance testing) and agree that the products given off when polyols and isocynates are heated are potentially nasty, and the gasses and vapours are flammable, hence the fires seen on the videos I posted here earlier this year in the Grenfell Tower thread on the PIR cladding tests.  However, on that same thread you will also find a video I posted of an EPS facade fire.  Given that, chemically, polystyrene is significantly more flammable than PUR or PIR, that isn't surprising.

 

I suggest a look at the basic polymer chemistry and, in particular, the way that these products react when heated and subject to oxidation might be useful.  The differences between the extreme flammability, and ability to sustain a fire, that polymers like polystyrene exhibit, particularly when compared to foamed polyol/isocynate , are very clear.  Both will contribute to fire, but polystyrene is inherently flammable, whereas it is the heat breakdown products of isocyanates, in particular (as used on Grenfell Tower) that are flammable, the core foam chars, rather than burns (there are lots of images of the charred residual PIR on Grenfell Tower, for example).

 

The chemistry of flame propagation and development within, or on the surface of, these products is fairly complex, particularly with PUR/PIR, where outgassing is the most significant cause of flammable product release.  Polystyrene, be it XPS or EPS is easier to get to grips with, as the entire polymer is flammable in any form.  Both can be treated with additives to reduce the initial flammability; things like the addition of melamine to a polyol before foaming  can reduce flammability, for example.

 

Don't believe everything you read on Wikipedia - check the flash point of hydrogen cyanide for example, then look back and see if you think it's realistic that it would be released without igniting in a fire...............

Edited September 26, 2017 by JSHarris

[Alexphd1]

@Triassic  I am can't comment on strength of the cross ties but i thought it would be easier to get a good pour with less bulk in the center core for the cement to flow around. 

[Triassic]

I've started to get quotes back from the various companies and interestingly they are all very close in price. I had thought there'd be a wide spread of prices, clearly they don't compete on price.

[willbish]

Out of interest @Triassic which product have you gone for in the end?

[Triassic]

In the end I’ve decided to go with Amvic. They were a bit of a late entry into my selection process, the decision was mainly down to price, they were significantly cheaper than everyone else. 

 

For or those who like to see progress, here’s a photo of the hole for the walk in basement.

Edited January 28, 2018 by Triassic

[Russell griffiths]

More pics as you progress please @Triassic I spoke to amvic at the build show on Saturday and also nudura, both seem very knowledgable, the nudura product looks to have had a lot of research put into it. 

The nudura rep also lives 15mins away from me so could be good to get a bit of a friendship going. 

 

[Triassic]

These test results might be of interest

http://www.nudura.com/docs/default-source/tech-centre/NUDURA_FORM_CAPACITY_TESTING.pdf?sfvrsn=0

 

Edited January 28, 2018 by Triassic

[Alexphd1]

We went with nudara as there price was the same as amvic but there wall bracing was cheaper which swung it. There is amvic build just a few minutes up the road and was impressed the block aswell. Would happily use either on next build.

If you are doing the icf yourself have a look at the rebar tie machine, it is a expensive luxury but makes life so much easier. We bought ours on eBay and hopefully break even when we offload it.

[Alexphd1]

+1 for more pics. Just out of curiosity what's the spec of rebar in basement wall, next build has a three sided basement as well. 

[Big Neil]

On 15/09/2017 at 13:40, jack said:

What about putting strips of something over the webs (or maybe every third of fourth web) that will be detectable with a stud-finder? Would aluminium tape work?

 

I hate you - that was my next million pound Idea - how about a wire embedded into the centre of the polypropylene strip near the front? Would something as soft as solder work?

[Big Neil]

Actually I suppose if the middle stud on each block had a metal covering/was just metal full stop, this would suffice wouldn't it?

[MuddyOne]

Found this thread- shame it seemed to stray from the original question and went down a rabbit hole around foil - and vermin attack - valid points that needed making, but seemed to be flogged to death.

 

So wished to pull this back to the original thread.  I am looking at ICF.

 

There seem to be two types, polystyrene (or similar) Lego blocks or woodcrete based forms.  

 

I prefer woodcrete due to:

 

1. Future fixings not having to find the webs 

2. Thermal mass not insulated so works

3. The polystyrene is non structural and has fire concerns.

 

I am no expert,  I am edging towards Velox due to lack of thermal bridges and ease of construction (I am a self build).

 

Any others I should be looking at and any feedback from using Velox?  

 

Cheers

 

 

 

 

[Russell griffiths]

I have said this so many times I’m getting a bit annoyed 

go out and play with some blocks spend a day on site chucking it about, cut some up

you say you are going to diy it, so that means YOU will pick up every block, get it up two lifts of scaffolding 

 

you cannot make a choice on paper or one based on thinking you won’t be able to put a picture on the wall, what a load of shit. 

Go to three sites and then make your choice 

 

i did and and then I chose the most expensive one, not because I wanted to spend lots of money, but because I thought it was going to be easy to use, offered a reasonable insulation level, was strong, went up quick, didn’t need air sealing,etc etc

 

do not choose a product because it is cheap, at the end of the day adding a parge  coat to a whole house will cost loads be it in time or materials it’s an extra step you could avoid. 

Edited July 10, 2019 by Russell griffiths