I haven’t had a really good rant for a long time, so here goes. Indulge me – You'll definitely learn something and you might even be entertained.
I’m angry because the ICF myths and misinformation continue. I’m tired of hearing people say all ICFs are alike. ALL ICFs ARE NOT ALIKE!
Some are utter garbage and should not be legal. Others are not legal at all. Some are OK, a few are good. Polycrete Big Block, though, is so far advanced that it can hardly even be compared to the rest. Am I biased? Of course I am! But I’m not just blowing smoke and you don’t have to take my word for it. Just stick with me for a few minutes, look at the evidence and decide for yourself.
Insulating concrete forms (ICFs) are forms for building reinforced concrete walls. They’re made out of expanded polystyrene foam. These forms stay in place after the concrete cures and serve as insulation for the building. Sheetrock attaches directly to the ICF surface on the inside and siding -- brick, stucco or whatever you like -- attaches directly to the outside surface.
It’s a great way to build highly energy efficient buildings that can stand up to Mother Nature. As long as it’s done right. This construction method has been around since the 1960’s. Very popular in Canada, it’s become more widespread in the USA over the past several years.
Let’s all agree that we have building codes for a reason. If you aren't on board with that, you can stop reading now and go back to checking the baseball scores. This article is not for you.
A series of basic tests is required for an Insulated Concrete Forming system to be approved by the International Code Council (ICC) – the governing body that most U.S. building codes rely on. The tests need to performed by an approved independent testing service. Most often, that’s Intertek, one of the largest and most well-known building materials testing laboratories on earth.
We recently spent several days poring over technical data available on websites of all the major and some minor ICF manufacturers in North America. It’s been an eye-opening experience.
There is a “Fastener Test” in which a screw is screwed into the fastening system of an ICF test wall. The wall is a complete wall with concrete cured under controlled conditions. Using a carefully calibrated machine, the screw is then pulled out of the fastening system and the pounds of pressure required to pull out the screw is recorded. They do this several times and calculate the average.
Get this: One mainstream ICF company didn't like the results they got from Intertek, so they went out and hired a screw supplier to run their own test. Surprise! The screw supplier discovered that if you put a screw in a very specific location on their plastic stud (they call it a "Sweet Spot") you can get 500 lbs resistance. And they publicize the heck out of that. Can you imagine that happening in the field? This is the kind of misinformation and garbage people have to wade through.
OK, back to business. The other screw test is a shear test. They test how much lateral (sideways) pressure can be applied to the screw before the system fails. The screw pulls out, the fastening web/strip breaks or the screw breaks. They also do this several times and record the average. This is important because you want to be confident that if you screw kitchen cabinets, bookshelves or a flat screen TV to the wall, it will stay there – even when a four-year old tries to climb on it.
Let’s talk about results. On Fastener tests, the common plastic tied ICFs have screw pull ratings of about 125 – 150 lbs. Polycrete’s was an average of 311 lbs. with a maximum of 359 lbs. There was only one other ICF we could find that was in our league.
On the lateral shear test, Polycrete Big Block averaged 375 lbs. with a maximum of 420 lbs. The others we found averaged 235 lbs. That’s almost 37% weaker. We’ talking about all the mainstream ICFs. There’s only one in the same league as Polycrete on the screw pull, but on the shear test, the screws reportedly snapped off pretty easily in that one.
These are all mainstream ICF products, and as you can visit their websites and see from the independent testing reports, they’re woefully weaker than Polycrete Big Block.
Other tests are “flexural” and “compressive” tests where they test the actual strength and density of the polystyrene panels. The “flexural” test measures the bending strength of the EPS panel and the “compressive” test measures how hard you have to push on it in order to sqwoosh it.
Most ICFs are made from “Type II” polystyrene, and that means the manufacturer uses anywhere from 1.35 to 1.5 pounds of polystyrene per cubic foot. The greater the density, the stronger the form and the more likely it will be to hold concrete. The test results should show that.
Basic stuff, but you need to know because when you fill an ICF wall it’s a lot like dumping concrete into a throw-away coffee cup. You want to have a fighting chance of not ending up with loose concrete flowing all over the jobsite.
Then come the fire tests. I like fire. There are two different testing protocols. This is where they measure the fire resistance of the entire wall system and also the burning characteristics of the ICF components. I say “components” because if the ICF has plastic cross ties, they have to test the EPS panels and the cross ties separately.
In the first fire test, they build a test wall -- again with the concrete cured to a specified humidity level so all ICFs can be compared like apples to apples. The wall is usually eight feet wide and eight feet tall. They wheel the wall into a furnace, heat it up and record what happens. After a while they turn a fire hose on it and see what happens. They record the results. This is serious business, and it does not come cheap.
Plastic cross ties are usually made from polypropylene and that stuff catches fire much faster than the EPS. The EPS has a flame retarder in it and the polypro doesn’t necessarily have one. For this reason, 6” thick ICF wall systems with steel cross ties usually have a four hour fire rating and the plastic-tied ICF systems are generally only good for three hours. An important consideration if having your building collapse in a fire worries you.
The second burning protocol calls for putting the ICF components into a furnace and recording how long and at what temperature the EPS panel and the injection molded plastic cross ties flame, melt or both.
They also measure the smoke generated and the “flame spread index”. For the record, the smoke generation and flame spread with nearly all ICFs is significantly less than with wood, so we can kill that myth once and for all.
Nearly all the EPS in North America comes from one of a very small handful of manufacturers of raw polystyrene “beads”. Those polystyrene bead manufacturers all use the same flame retardant chemical and supply the beads with the flame retardant included. Burning characteristics of the EPS itself don’t vary much from ICF to ICF. It’s generally the cross ties that make the difference, but you have to do the test anyway so you know the ICF is not made with some fluky pirated polystyrene.
The most interesting test of all is not yet actually required in the USA. But the fact it’s not required doesn’t mean the results aren’t very interesting to read. This is the infamous “Forming Capacity Test.”
Canadians have used ICFs much more widely than we lower forty-eighters, so they are far ahead of us in their general knowledge and experience with the technology. Canadian building code officials know that keeping the concrete inside the ICF wall is important for safety and efficiency. Canadians are also persnickety – they don’t like cheap junk. So they insist on a test that shows just how strong the ICF system is under real concrete pumping conditions.
For the Forming Capacity test, the ICF manufacturer builds an ICF wall using their published recommended construction process. Bracing is done according to the manufacturer’s published instructions. The testing scientists then install sensors in at least nine different places on the wall. These sensors measure the thickness of the wall. The testers also measure the straightness or plumbness of the wall.
Four feet of concrete is then pumped into the ICF wall and the concrete is vibrated using specific equipment and specific techniques . Fifteen minutes or so after the first lift is placed, a second four foot lift is added and that is vibrated as well in order to get proper consolidation of the concrete. Then the readings on the nine sensors are recorded, and that tells you how much the EPS foam panels have bulged from the weight of the concrete. If the ICFs break and blow out the concrete, that is noted as well.
The ICF manufacturer can choose what thickness of ICF wall he wants tested, and their designated personnel build the wall. The thicker the wall, the heavier the concrete and the greater the chance of bulging or blow out. Most ICF manufacturers choose to test a 6” wall. Polycrete tested a 10” wall.
Besides Polycrete, only one other main stream ICF supplier makes their forming capacity results available on the website. That company tested a 6” thick wall. It was not plumb when they built it, and it got further out of plumb when the filled it with concrete. They made no attempt to straighten it. I’m not making this up, it’s in the report. “Why did they build it out of plumb?” you might ask.
Experienced ICF installers know that residential grade ICF walls move when you pump in concrete, so they tilt it in towards the bracing before pumping. That’s because it’s a lot easier to push it out into plumb than to try to pull it back (think screw pull test). We’re going to assume that installers in the field remember to try to plumb it up after pumping. Oh. That wall bulged up to 3/8” also. The testers call that measurement “deformation.”
Polycrete tested a wall with 9-5/8” thick concrete – over 60% more concrete than the plastic-tied one. The Polycrete Big Block wall had zero, zero, zero deformation. Zero. Can I say that again? ZERO. It moved a nearly invisible 3 millimeters out of plumb over sixty-four square feet of wall surface, and that was easily fixed with a minor adjustment of the bracing.
Don’t take my word for it, remember, I’m biased. Look at the Intertek reports. You don’t have to be Einstein to figure out which ICF is stronger.
Now you may ask, “Who cares and why?” Well, deformation is important because if the wall is all bulgy and snaky, you have to deal with it before putting up sheet rock. The common way is to bring in a team of laborers with big rasps and they shave off the high spots where the walls bulged. Undesirable things come from this: Construction delays and labor costs. You also reduce the R Value or insulation properties of the wall because the insulation is now thinner.
What if the ICF system has fastening strips (studs) exposed on the surface of a bulging wall? Flattening it will be impossible. The only way to fix that bulgy and snaky wall is by furring and shimming. More labor, more materials.
Then there are the fringe systems, and that’s where the ICF world really gets problematical. For example, there’s a heavily marketed, vertical, knocked-down system that is more like a traditional cast in place concrete form. It’s a very labor intensive and consists of a lot of parts to be assembled onsite. It’s reported to be prone to blow outs, and knowledgeable ICF people tell us they won’t touch it with a ten-foot pole.
They do a lot of marketing, but here’s the problem: That system has not undergone any ICC testing that we are able to find. No fastener tests, no compressive tests, no flexural tests and no burn tests. No forming capacity tests. No nothing.
So we called the company. No, we didn’t tell the lady who answered the phone we were from PolycreteUSA, we just said we were an interested consumer. We asked if they would share their ICC test results. Well, the phone was covered with a hand or something, there was a lot of whispering in the background, and finally the lady came back on and said no, they did not have any ICC test results to share.
She confirmed our suspicion that the vertical ICF is not a real approved, code compliant ICF system. The EPS was tested and approved for use as a perimeter wall insulation only. There are a lot of other restrictions to its use. You can read the report for yourself. Look up ESR-1006 on the ICC-ES website. This is the report for the foam panels they claim to use in their system.
Some people may ask, “What about Pensmore?” It’s a gigantic house. It’s under construction (has been for a long time) and it’s being built out of the that system. If you look at pictures of the building under construction, you can see that the foam panels seem to be shored up with corrugated steel, and that seems to support the claims of installers who say it’s a weak system.
The owner is building this house for himself and he chose a location that has no building regulations. The structure is not subject to inspections. He told the New York Times that building codes and inspections would “complicate” his efforts. Don’t take my word for it, read the NYTimes article.
There are other untested fringe ICF products out there as well. Most common ICFs with plastic ties are made by contract manufacturers—companies that specialize in making things out of expanded polystyrene. The same companies that actually manufacture many ICFs also make packaging materials, take out containers and coffee cups.
Many brand name ICF companies do not actually own any manufacturing facilities. They’re really just R&D, sales and marketing companies. Instead, they pay a machine shop to make them a special mold, they deliver it to a contract EPS molding company and cut a deal for the molding company to make their ICFs to order. The plastic cross ties can be bought from China by the container load. One EPS molding company may make several different brands of ICF under different contracts.
Sometimes these EPS molders get their own ICF molds and make black-market no-name ICFs. They’re untested, have no approvals, and get sold to unsuspecting do-it-yourselfers or nefarious fly-by-night contractors. These ICFs are often weak and substandard because they’re made with lower density foam prone to bulging and blow outs. They give a bad name and black eye to the entire industry. Cheap contractors want us to try to compete with them price-wise. We won’t do it.
Polycrete Big Block is manufactured on Polycrete equipment in Polycrete factories, to Polycrete standards. We do our own steel fabrication and mold our own EPS. We use no contract molders. Our EPS panels have a steel cross tie system and welded steel wire mesh inside the polystyrene panel for strength. No other ICF has this feature. It prevents bulging and blow outs. That sets Big Block™ very far apart from the crowd.
Big Block™ stands up to 1,600 lbs per square foot of lateral pressure. We invented a machine to measure that strength. We actually got it up to 2,000 lbs and the machine broke before the form did. But we only claim 1,600 lbs. It’s enough. We also measured a bunch of conventional ICFs, and none of them passed 800 lbs. It’s that forming capacity thing.
Big Block™ is also the largest ICF anywhere. Standard size is 2’ x 8’. Install sixteen square feet of wall in one motion and that’s faster than any other ICF on the planet. Yes, there is another 8’ long product, but it’s only 18” tall and it has big clunky plastic cross ties that impede the flow of concrete and can break if they get hit by a rock while pumping concrete. Blow out city.
Cheap materials don’t make a lower cost building if they result in added labor costs, more headaches and construction delays. Who wants angry and frustrated customers? In the end, you get to decide. Are straight, flat walls important to you? Is finishing on time and on budget important? Is jobsite safety and disaster performance important?
Polycrete’s mission is to make it easy to build energy efficient structures that stand up to Mother Nature. Whether it’s by partnering with other technologies to reduce steps in the construction process or bringing in consultants to help you take advantage of energy efficient tax breaks. We constantly look for ways to make your life easier and building experience better.
Two words about installers: Due diligence. A bad installer can screw up the best ICF in the world. Believe me, I’ve seen it. Pick them carefully. PolycreteUSA seeks out commercial concrete contractors and trains them to install our ICFs. They understand the challenges of commercial construction and already know how to work with concrete. Many ICF installers are wood framing crews trying to move up the food chain. Some work out fine, a lot don’t. Once again: Due diligence.
PolycreteUSA is not interested in one-offs. We want to be your ICF supplier for life. We’re on the team. We are always going to deliver a premium product, we don't snow you with marketing hype and we always have your back.
I hope you found my rant worthwhile. Thanks for your time.