I'm in the design stage of an addition to our beach cabin in the San Juan Islands (Northern Washington State). I've been reading as much as possible on the various ICF systems available, talked with factory people and watched some of the many videos. There are a couple of ICF builders in my area, as well I've got a lot of stick frame building under my belt, have a good friend who is a retired concrete bridge & commercial building builder, and several talented people to help - so I am leaning toward DIY. I also have a retired ICF contractor who will help with any stage I need. So I'm feeling pretty good with the DIY aspect of the job. Question: Am I crazy to attempt a DIY ICF project? The Quad-Lock factory is very close to my place, so I am leaning toward using their system. I am ready to hear the "bad stuff" about Quad-Lock, (if there is any) as their web page "only" tells me everything "good" about their system. I'd like to ask you, for your comments on Quad-Lock. I also have pretty easy access to FOX and ARXX, but I like the feature that Quad-Lock lets us build a rebar cage (if we want to) easier since that system comes KD (knock down) and we assemble each block. Your comments are really appreciated. PS: I don't want a bunch of back and forth about how great another brand is - or isn't. I just want the lowdown on Quad-Lock, precautions, what to understand about it, or what to look out for... or maybe it is as wonderful as the factory says!

Posted By Roger R on 06 Jul 2013 07:15 PM
I'm in the design stage of an addition to our beach cabin in the San Juan Islands (Northern Washington State). I've been reading as much as possible on the various ICF systems available, talked with factory people and watched some of the many videos. There are a couple of ICF builders in my area, as well I've got a lot of stick frame building under my belt, have a good friend who is a retired concrete bridge & commercial building builder, and several talented people to help - so I am leaning toward DIY. I also have a retired ICF contractor who will help with any stage I need. So I'm feeling pretty good with the DIY aspect of the job. Question: Am I crazy to attempt a DIY ICF project? The Quad-Lock factory is very close to my place, so I am leaning toward using their system. I am ready to hear the "bad stuff" about Quad-Lock, (if there is any) as their web page only tells me everything "good" about their system. I'd like to ask you, for your comments on Quad-Lock. I also have pretty easy access to FOX and ARXX, but I like that Quad-Lock lets us build a rebar cage (if we want to) easier since that system comes KD and we assemble each block. Your comments are really appreciated. PS: I don't want a bunch of back and forth about how great another brand is - or isn't. I just want to low down on Quad-Lock, precautions, what to undersatand about it or what to look out for... or maybe it is as wonderful as the factory says!

I don't think it is out of line to attempt a DIY ICF job based on your past knowledge and ability to access current concrete/ICF help.


From what I have read Quad-Lock is NOT as strong as other blocks that come with factory attached internal ties/strips. This will come into play during the pour and vibrate, the wall might have to be braced a lot more as blow-outs could happen more easily with this type of block. It is a "knock down" block which is not that great of a block, IMHO. If you are worried about shipping, blocks like Nudura work well because they are hinged and fold flat.

If you want a DIY block for ICF, I don't think a knock down block is going to be kind to you.

I built my home DIY with experienced help during the pour using LiteForm ICF which is similar to Quad-Lock in design. No problems. No blowouts. I liked the flexibility the knock down block offered. Cutting the forms to length was easy using a chop saw. Changing the height of a wall was relatively easy by running the foam through a table saw and ripping to the desired height. Knock down is a little more time consuming because you assemble as you go including cut-to-fit and building your corners.

One disadvantage of knock down forms is that they don't have continuous furring strips to attach stuff to. This might be an issue of you are installing vinyl or plank type siding. Not so much with drywall interior and stucco exterior. I'm installing brick, so it shouldn't be an issue.

Posted By arkie6 on 07 Jul 2013 05:43 AM
One disadvantage of knock down forms is that they don't have continuous furring strips to attach stuff to. This might be an issue of you are installing vinyl or plank type siding. Not so much with drywall interior and stucco exterior. I'm installing brick, so it shouldn't be an issue.

Arkie, Thanks for your info. Quad-Lock has their FS block, which does have furring strips moulded into the foam - they also explain that you can screw into their 'connectors' if you find that the connectors are the correct space for you. You mentioned not having furring strips shouldn't be a problem for installing sheetrock. How's that? Don't you need to screw the rock into a plastic connector or furring strip? Do people use Green Glue, or silicone on ICF, to help hold sheetrock?

Posted By Roger R on 07 Jul 2013 01:55 PM


Arkie, Thanks for your info. Quad-Lock has their FS block, which does have furring strips moulded into the foam - they also explain that you can screw into their 'connectors' if you find that the connectors are the correct space for you. You mentioned not having furring strips shouldn't be a problem for installing sheetrock. How's that? Don't you need to screw the rock into a plastic connector or furring strip? Do people use Green Glue, or silicone on ICF, to help hold sheetrock?

Having the plastic strips to attach drywall, artwork/paintings, shelves, cabinets, trim mold, electrical outlets, etc, is a vital part of making life easier for the finishing trades. If an ICF block has attachment strips every 8" oc, the drywall people can simply lay the drywall flat and run the screws into the webbing. You do NOT want to be gluing drywall and messing around with that.

One thing to remember is that you don't want to have the electric drill speed on high because the plastic strips heat up and can melt and strip out easily. A wood stud can take a high RPM screw but a plastic ICF web is more sensitive to the heat generated by the high speed drills and over tightening. Slower RPM and don't over tighten it.

Here is some info: Drywall Attachment

Plastic (usually polypropylene) fastening strips were introduced into ICFs in order to make a lower cost product that could be easily sold to DIY homewowners with little knowledge of construction. It is one of the silly characteristics of insulating concrete forms that makes it hard for commercial construction professionals to look at our industry as anything other than a quirky fringe product.

In my opinion, plastic cross ties and plastic fastening strips are a safety issue. They cannot hold a screw like steel does. That means they cannot hold a brace, sheetrock, cabinets, a flat screen or even a painting like steel does.They do not perform as well in a fire either. Don't take my word for it, look at the facts. Here's a recent blog post http://polycreteusa.blogspot.com/2013/06/i-havent-had-really-good-rantfor-long.html (Administrator, this is not a plug, it's an expose).

There are two or three manufacturers of ICFs with steel cross ties and steel fastening strips. I know about the ICF manufacturing process. There is no reason why any of the main stream ICF companies cannot make a steel version.

Posted By BrucePolycrete on 08 Jul 2013 08:27 AM
Plastic (usually polypropylene) fastening strips were introduced into ICFs in order to make a lower cost product that could be easily sold to DIY homewowners with little knowledge of construction. It is one of the silly characteristics of insulating concrete forms that makes it hard for commercial construction professionals to look at our industry as anything other than a quirky fringe product.

In my opinion, plastic cross ties and plastic fastening strips are a safety issue. They cannot hold a screw like steel does. That means they cannot hold a brace, sheetrock, cabinets, a flat screen or even a painting like steel does.They do not perform as well in a fire either. Don't take my word for it, look at the facts. Here's a recent blog post http://polycreteusa.blogspot.com/2013/06/i-havent-had-really-good-rantfor-long.html (Administrator, this is not a plug, it's an expose).

There are two or three manufacturers of ICFs with steel cross ties and steel fastening strips. I know about the ICF manufacturing process. There is no reason why any of the main stream ICF companies cannot make a steel version.

And there is simply no reason they would want to. That why they are mainstream. We've been through this bs before. Any of the plastic webs will hold all the weight that is needed. We don't hang kitchen cabinets with one screw. Drywall only weights 1.6 pounds per square foot. If your product is so bad that the only way you can promote it is by fear mongering and ranting, I guess we don't have to worry about it ever being mainstream.

For those that care, the reason almost all mainstream producers use poly webs is that they are highly resistant to thermal bridging. If you care to go to Polycretes site you will find their thermal characteristics of their big block. If you look at how fast the temps drop across the assembly you will understand just how conducive steel is to temperature. I live in an area with a design temp of -32 C and have never seen interior wall temps that low.

I could spent time to go through Bruce's rant line by line and debunk this nonsense but I'm sure most of you can as well. I'll just point out that in most jurisdictions the only thing that differs in a 3 hour and a 4 hour wall is the thickness of the concrete in the wall. If you want to get technical, the exposed steel and its ability to conduct heat into and through the concrete and the thermal expansion of steel, will be a much bigger concern in a firewall than plastic webs.
In spite of Bruce's blathering, I don't doubt that Polycrete will be an acceptable form for some of you. I won't use it because I don't use forms that won't lock together bottom to top and side to side. Also in this day and age there is no excuse for not having a fully interlocking corner piece. These are just personal preferences but make a big difference on the job site.

FBBP I understand that you want to keep doing things the way you're used to doing them. It's a natural quality. I have only two material comments on your post. The first is to correct your misconception that Polycrete's steel ties create any thermal bridging. It's not the case, as the steel web which reinforces Polycrete's EPS panels and the integrated fastening strip is set inside the polystyrene. It is not exposed to the outside environment. There are lines molded into the outside of the panel to indicate the location of the fastening strip and cross tie system. The thermal analysis you see on the website is a computer model showing performance of the wall with an extreme temperature variation from inside to outside. I agree it's a bit unrealistic in most climates, but it's just an illustration.

The other exception is with the term mainstream. I made the mistake of using the term first, when I should have said simply "main ICF manufacturers". That's the problem in a nutshell, there is nothing mainstream about ICF and it's because so many of the products offered to the market come across as toys that are not taken seriously by construction professionals. Believe me, I know because I climb that mountain every day. It's an easier sell to a DIY-er, "Hey, you can do this yourself and you don't even need power tools."

Numerous ICF blocks that use plastic webbing are used in commercial applications. They've used Nudura and Fox Blocks when building a fire station. Many commercial buildings, let alone a fire station, and they used a block with plastic webbing with no problems. As far as the fire issue. The EPS will melt way before the plastic ties will melt. With no direct fire fuel source, the EPS and plastic ties do not carry their own fuel or flame. They self extinguish and require an outside fire/fuel source.

Back to the question at hand. Attachment strips are a big plus and will make the rest of the build go that much more smoother.

Lbear, Just because residential grade ICFs have been used to build commercial buildings, it does not make them commercial products.On the contrary, the many commercial (and military) ICF disasters make it abundantly clear that there's a difference between a residential grade ICF and a commercial one. In my view, there are only three commercial grade ICFs available in the USA, but I'm not about to name them. With regard to the fire issue, the fear among construction professionals is that plastic ties melt and create a path that allows flame to travel through the wall. This seems to be the reason that Polycrete's 5-5/8" concrete wall has earned a four hour fire rating while the plastic tied ICFs are mostly rated at 3 hours for a 6" wall.

Posted By BrucePolycrete on 08 Jul 2013 02:51 PM


In my view, there are only three commercial grade ICFs available in the USA, but I'm not about to name them.

If Bruce won't name the other two "Commercial Grade ICF's - can somone else name them?

Posted By BrucePolycrete on 08 Jul 2013 02:51 PM
Lbear, Just because residential grade ICFs have been used to build commercial buildings, it does not make them commercial products.On the contrary, the many commercial (and military) ICF disasters make it abundantly clear that there's a difference between a residential grade ICF and a commercial one. In my view, there are only three commercial grade ICFs available in the USA, but I'm not about to name them. With regard to the fire issue, the fear among construction professionals is that plastic ties melt and create a path that allows flame to travel through the wall. This seems to be the reason that Polycrete's 5-5/8" concrete wall has earned a four hour fire rating while the plastic tied ICFs are mostly rated at 3 hours for a 6" wall.

A 4 hour vs. 3 hour fire rating is not going to make a difference in block choice. Most residential structures have only 1 hour ratings with wood frame. Besides Nudura achieves a 4 hour fire rating with their ICF and 1/2" drywall. As mentioned before, the EPS foam will melt long before the plastic ties will melt. The plastic ties are rated at 700F for the Flash Ignition Temperature. EPS begins to melt at 190F.

The whole metal vs plastic tie is a wasted debate. In the end it's the 6" of concrete that makes the structure.

Roger - residential/commercial is just a figment of Bruce's imagination. Just like their wood and steel cousins, foam forms don't really care if the are out in the sticks or on the twentieth floor of some high rise.

Disasters are the makings of installers not the forms.

No actual building "professional" worries about flames penetrating the convoluted path of the webs, even if they where to melt all the way through 6 inches of concrete. It would have to be some kind of fire for the heat to penetrate to the core of 6" wall even if there was a fire load on both sides. It would be virtually impossible with the fire exposure from one side only. I would sure like to see Polycretes test results for 4 hours on a 6" wall with no drywall or other coating.

To say that there is no thermal bridging because the steel is set inside 1/4" of eps is like saying I'm not going to freeze to death outside at minus 32 because my t shirt separates me from the cold. Really? The 1/4 inch provides all of R-1 and then its a super highway till it hits the R-1 on the other side. It's thermal bridging capabilities are further enhanced by the fact that is is a wide metal strip (a lot of surface area) attached to the ties that absorbs and radiates the heat to the outside.

Bruce, can't you see that by attaching the rest of the ICF's you are bring down the whole industry and cutting your own throat? There is nothing about Polycrete that makes it better than other forms and maybe not that many things that make it worse (except that they don't lock together and that they have high thermal bridging.) Just support the whole industry and take your market share of the increase.

FBBP continues to argue that the sky is green when it is clearly blue. If he were to just do a small amount of research rather than relying on anecdotes and his personal assumptions, he would see that. Here's a few comments to clear up more of his misconceptions:

Polycrete's steel reinforcing web, cross tie and fastening system is recessed an inch and a half below the EPS surface and there is no thermal bridging. All of Polycrete's ICC test results are presented on the PolycreteUSA website and available to all for download.

Residential grade ICFs are those that are suited for building single family homes. They work well when the walls are 8 or 10 feet tall, and the linear runs are 20 feet or so with lots of window openings and bump-outs. Commercial grade ones are bigger, stronger and can easily be used for tall walls -- up to 20 feet or more and wider walls -- up to 24" of concrete with linear runs of up to a couple hundred feet.

Polycrete ICFs do not lock together because there's no need for them to lock together and why would you want them to anyway? The little nubs and holes just cause extra waste and slow you down. Polycrete Big Block's great strength and ship lapped edge profile uses the weight of the concrete to lock the forms together. There is technology and engineering in the Polycrete product that people wedded to conventional ICFs may not initially notice because they come at it with certain assumptions.

I will agree that the installer plays a big role. A crummy installer can screw up anything -- and boy have I seen that! Polycrete has engineered out many of the problems inherent to the residential grade and earlier generation ICFs. Installers and sales reps who have been able to make a living by mastering the quirks of those products are threatened by these advances.

I will continue to rail against the poor quality ICFs that some manufacturers try to foist on an unknowing public. I will also continue to call out those who insist on pushing products that are entirely unsuited on penny-wise and pound-foolish GC's. If you think that military ICF disasters like Ft McCoy, Ft Campbell, Youngstown, OH and Pittsburgh, PA don't give a black eye to the ICF industry, you are the problem and not the solution.

Keep insisting that this junk some in our industry try to pass of as a commercial construction product is viable and you will always be part of a fringe industry that no responsible professional takes seriously.

It's the same thing being repeated over and over. Here, this post is 3 years old, sound familiar?

Posted By BrucePolycrete on 29 Oct 2010 05:05 PM

 The problems with plastic webs include:
Failure in a fire: the web melts and the void allows heat and flame to spread through the wall
Air infiltration: EPS breaths. Since concrete does not adhere to plastic, there is necessarily a series of voids along the plastic webs. Those voids allow air to infiltrate -- that comes from the Air Barrier Association of America.
Plastic is weaker than steel. Steel webs mean fewer blow outs, no question.
Since the steel attachment strips are recessed beneath the surface of the foam there is no thermal bridging to worry about.
Finally, STEEL is much more satisfying to work with and build with than some flimsy old plastic stuff. Face it, do you want a building made of STEEL or plastic?

I love the part where it is equated that plastic webs vs. steel webs as effecting the strength of the structure. Are you serious? The attachment strips whether plastic or steel have absolutely NOTHING to do with the final structures strength. It's the 6"+ of concrete and rebar that make or break the wall structure, not the webbing.

And I quote, "Face it, do you want a building made of STEEL or plastic?"

Back to reality. Thermals have been shot of a ICFs that have steel webs instead of plastic webs. The thermal shots show that the steel webs will bridge heat or cold from the outside to the inside of the home.

Schock makes thermal bridge breaks for rebar when concrete decks are used. They have well documented that the rebar inside concrete will bridge heat/cold from the outside to the inside unless it is thermally broken.

Posted By BrucePolycrete on 08 Jul 2013 08:24 PM
If you think that military ICF disasters like Ft McCoy, Ft Campbell, Youngstown, OH and Pittsburgh, PA don't give a black eye to the ICF industry, you are the problem and not the solution.

References please. A non-exhaustive search on Google turns up nothing about military ICF disasters.

That's right, Lbear the more things change the more they stay the same. You know nothing about ICF except what you've read on this forum. dmaceld, there are people on this forum (other than me) who can answer your questions abut Military ICF disasters. There are even some who have been called in to fix them. The industry has swept them under the rug quite effectively. We're working hard to fix that. We helped write the UFGS spec for ICF construction that the Corps of Engineers released last February and we continue our efforts to get the garbage products and unethical installers eliminated from the program.

Posted By Lbear on 08 Jul 2013 09:00 PM

Schock makes thermal bridge breaks for rebar when concrete decks are used. They have well documented that the rebar inside concrete will bridge heat/cold from the outside to the inside unless it is thermally broken.

Lbear, Have you used these items?

Posted By Roger R on 08 Jul 2013 09:39 PM


Lbear, Have you used these items?

I have not but they are very popular in Europe and now in Canada. The US is a little slow in changing their building techniques. They have been used in many commercial applications for decades. Click here

They will do small residential and they provide a way to thermally break an exterior cantilevered or non-cantilevered balcony slab transitioning into an interior slab.

Building Science Article

Posted By BrucePolycrete on 08 Jul 2013 09:35 PM
That's right, Lbear the more things change the more they stay the same. You know nothing about ICF except what you've read on this forum.

Another incorrect statement. My research into ICF has included studies and research articles from Building Science, ORNL, Green Building Advisor, ICF Magazine, JLC, and many other sources. I have personally been on quite a few ICF builds, both commercial and residential.

Insulting & degrading people doesn't win them over as customers. That is sales rule #1.

Let the consumer chose between plastic or steel webbing but please don't claim that plastic webbing in forms like Nudura and other reputable blocks is somehow inferior. They both have their pros and cons.