Talk:Insulating concrete forms

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I have a small problem with some of the editing to date: it is said that "Post-and-Beam" (or "screen grid") systems have no fire resistance, but that is, perhaps unintentionally, misleading. It implies that this design is dangerous, compared to the other design types, but the fact is that if a fire gets to the stage where a small opening in the concrete will allow more material to be combusted, the building is a total loss in any case. The post-and-beam/screen grid design allows a relatively small amount of concrete to be replaced by EPS or other foamed plastic, thereby increasing the insulation value of the overall wall structure. Since the plans for an insulated concrete form building are checked by structural engineers, and the local building authorities check the plans for ALL buildings, the post-and-beam/screen grid type of product are perfectly safe, from fire, structural, or any other standpoints, especially when one considers the comparison to traditional wood structures.

It should also be noted that EPS will only burn if a direct flame is applied to it, and the resulting smoke is said to have only 5% of the toxicity of wood smoke.

I have an ICF home - the first to be built in Texas in fact. We used the 'Greenblock' system. It's been very noticable that there are very few insects in the home - and even after 8 years, we have not needed to have the house sprayed for Roaches - in previous houses we've owned in Texas, we needed annual spraying to keep things bearable. An all-electric home of 2500 square feet consumes $200 worth of electricity in the height of Texas summer - that's around half what a similar house of timber-frame construction would need. The claims for quietness are quite believable - but we built far from the nearest road or neighbour - so it would be pretty quiet anyhow. I'm hoping we never have to test the claims of tornado-resistance - but Greenblock claim the walls will survive 300mph winds - I'm more concerned with the roof and windows! SteveBaker 18:00, 16 June 2006 (UTC)

[edit] Screen grid vs. Flat slab ICFs

I have heard, and seen here, that screen grid ICFs are an "old", or "first generation" system, implying that they are in some way inferior. I want to challenge that "first generation" assertion, and then provide some reasons I think post and beam systems are superior.

Applying Occam's razor: Which is more likely to have come first, given the newly discovered insulating properties of EPS?
A. Create an intricate form such that poured concrete flows in a regular grid pattern throughout the wall.
B. Pick up two EPS slabs, support them somehow, and pour concrete in between.

I believe the "first generation" argument came from flat-wall competitors looking to make their more basic system look better. There are many, many flat-wall ICF manufacturers and, like all rumors, that which is repeated most often is that which is most often believed.

Which will give off more exothermic heat as it cures, a 6" monolithic concrete slab, or a grid of 6" diameter posts and beams? Which, then, is more likely to shrink away from the form, causing an insulation-negating, insect-inviting air gap?

Which wall weighs less, requiring less concrete and less extensive foundation work?

Which makes sense when, with properly engineered concrete and rebar, the grid-walled structure can be built to 8 residential stories, or withstand 200 MPH winds? A flat-wall may be made to go higher, and/or withstand stonger winds, but how much more is appropriate, or cost effective?

Which will insulate better, 2 slabs of EPS (usually 4" total), or those same 4" plus a repeating pattern of "nodes" where the insulation goes from one side of the form to the other?

I work for Amazon Forms and, compared to flat ICF systems, our Grid-Wall ICF blocks are heavier (requiring less pre-pour bracing), stronger than EPS alone (less prone to pour-day trauma, with no need to find a "sweet spot" to hang a picture), easier to apply external and internal wall coverings (ie: no mesh or scratch coat needed for stucco or plaster), and easier to add after-pour afterthoughts (like external hose bibs).

And we use 100% post-consumer recycled EPS, including the jobsite scraps from everyone else's ICF system.

So, tell me again, which system is inferior?

Randy@amazongridwall.com

OK - three issues here:

1. Firstly, your email address and what you tell us makes it very clear that you are associated with the 'gridwall' business - which makes it very hard for anyone to believe that you are unbiassed in what you say when you advocate that technology. Whether that's true or not - there is a strong PERCEPTION that this is the case. Wikipedia has strong policies against you advocating your business here - so please tread very softly!
2. Secondly, Wikipedia is not the place for these kinds of technical debates. Read WP:NOR to understand our policy here. We generally require evidence in the form of books or other unbiassed, non-commercial sources. So could you perhaps point us in the direction of such evidence to back up your assertions. A comparative review from a reputable trade journal (not one directly associated with the grid-wall business of course) - any government studies that back up your claims? Structural engineering books perhaps?
3. Thirdly, whilst I'm not in the business, I have owned homes built with both techniques - and I have to say that my personal experience leads me to disagree with almost everything you said. Our present ICF home (the first ever to be built in Texas - and using the 'Greenblock' system) has proven vastly better in practical terms than our previous house which was built with the grid wall approach (I don't recall the name of the exact construction system we used on that home) - of course I'm talking strictly as a consumer of the technology - I'm concerned about how cheap and effective the resulting home is - not with how tricky it was to put together. Certainly your claims that the ICF will have poorer insulation value or be somehow less insect-resistant has not proven to be the case. All that the heat of 100F Texas summers and the HORDES of insects we are plagued with here in Texas are a pretty tough test of the things you are claiming. We've lived in our present Greenblock house for seven years and our summer A/C bills are about 30% lower than we had with the grid system home (and 50% lower than with the conventional timber-framed house we owned before that). What's more, we don't see any insect infestations whatever. We have not had to have the house fumigated once in seven years - which could not be said of our previous homes. So - I am a little biassed - but as a result of consuming the technology - not because my business stands to profit from it or anything. (I work in computer graphics - I design flight simulators).

In the end, both systems are so far ahead of 'stick-built' houses, that we are truly arguing about the icing on the cake - but I would certainly say that my ICF home is 'next generation' compared to the grid wall approach. My findings are as a practical result of living in these buildings and not based on the kinds of "Which is more likely?" types of assertions that you present.

SteveBaker 20:42, 23 August 2006 (UTC)