Pros & Cons of Insulated Concrete Forms /ICF construction

In my last video, we toured a factory that produces Insulated Concrete Forms or ICF blocks. Today we’re going to look at how an ICF wall is built with Fox Blocks as well as the pros and cons of this type of construction. NOT SPONSORED.

Chapters
0:00 Intro to Fox Blocks
1:02 Types of blocks
2:10 So how do you build ICF walls?
4:00 Advantages of ICF
6:04 6-in-1 assembly
8:22 Disadvantages of ICF
10:30 Summary

All Fox Blocks are made of molded polypropylene plastic ties which secures two pieces of 2 ⅝” thick Expanded Polystyrene foam pieces. The distance between them can vary from 4” to 12”. The blocks have teeth so they interlock on the next block, like Legos. The blocks should be staggered in a running bond method to avoid continuous seams. Horizontal rebar sits inside the ties to strengthen the wall assembly. Concrete is poured inside this sandwich and vibrated to eliminate air pockets, pack the aggregate, increase the density and strength of the wall.

After excavating the site, the concrete footing is poured on the perimeter walls with rebar sticking out of them. Next, the corner blocks are placed to define the edges. Straight blocks are then stacked in a running bond, staggered layout towards the center of each wall. Rebar or reinforcing steel bars, snap into the polypropylene ties of every single ICF block. The concrete in ICF walls must have a slump of 5” to 6” which is higher than a concrete mix for a floor which may be at 3”. The aggregate in the concrete must be between ⅜” to ¾”.

Advantages: Strength of the wall. They will withstand hurricanes and tornadoes, floods and they are fire-resistant. Air-tightness provided you use good quality doors, windows and a roof. The continuous interior and exterior insulation prevents mixing of cold and warm air, thus reducing condensation and mold. They have 1 to 1.5 ACH. They have a HERS rating of 30-50. Low sound transmission, STC rating of 50. Good R value. Great DIY wall assembly. Fox Blocks uses full-height ties and they have an extensive BIM library.

Fox Blocks markets their wall as a 6 in 1 assembly. The EPS foam acts as a natural vapor barrier, and provides continuous double layer insulation. The solid concrete core acts as an air barrier. The polypropylene ties have inbuilt rebar support and also act as fastening or furring strips for any finish. Their reversible interlocking design saves construction time and reduces waste.

Disadvantages: It is more expensive than wood construction in the States. They are not as good in cold climates. Waterproofing is expensive. Running electrical and water lines through the house, and even installing electrical boxes in your walls requires you to melt and cut out the EPS foam or even the ties. Any connections to the outside have to run through PVC sleeves which are placed before the concrete is poured. ICF homes can have humidity issues if it isn’t properly ventilated. The walls also occupy a lot of space. Concrete has a massive carbon footprint and is pretty destructive to the environment. But you also need to compare the short lifespan of a poorly built wood home to the 100+ year lifespan of an ICF home. Remodeling the exterior walls of your ICF home is nearly impossible. Less forgiving construction.

I think homeowners are slowly going to demand better-built homes because of all the information that is available on the internet. Right now, most people are just concerned with interior finishes like the type of granite used, shiplap walls, and hardwood flooring. They don’t realize that the bones of the building should take precedence over the stuff that you fill your home with. I can see ICF homes becoming more and more popular especially with custom builds.
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#insulatedconcreteform #icf #diybuild #diy #construction #architecture #constructionscience

[trahim]

These are by far the best construction education videos I’ve ever seen. Well done.

[maryricalottman]

I'm a Spanish literature professor with no experience in engineering, architecture or design, but I find Belinda's videos fascinating. Keep up the marvelous work!

[MJ-pybm]

I’m a ex general contractor. I truly love ICF walls. When you build a home with icf walls; make sure to install good dehumidifier, it can regulate the moisture in the house. Waterproofing? In northern part of state applied spray tar on the basement walls; it is fast and cheaper instead of applying expensive layers of sheathing.

Thank you so much for your educational videos. It is good to hear from a architect views on the building. One of many things I see in usa 🇺🇸, not many people doesn’t know what is better way to build a house. The most production builders, they will skin the cat in the structural of the house and very poor quality carpenters and concrete. The most the walls not even level. They can’t even build a 50ft wall in a straight line. It is so sad.

The production builders just do a modern lipstick on interior finishes and make looks so pretty. The house will start breaking down in 5 years.

2nd.. the recent freeze happened In Texas; most of the pipes are broken from attic. It is not climate control. The pipes were exposed on exterior temperature; little bit of temperature changes and stayed in 15 degrees for few days; many Houses got damaged.

Do you think, the lessons ever learned? No, the production builders keep building same way. They are completely forgotten what is happened 2 weeks ago In Texas.

[Tech-Drew]

I'm a main-contract manager from the UK Belinda. Thank you for making these wonderful well researched videos. We have something called 'toolbox talks' over here as part of good practice (part of construction design nand managment) to give all staff a knowledge of what everybody else is doing basically. I watched your video on Laminated flooring finishes and insulation (neither of which are my fields but as an ex chippy I'm going to re-do ours at home) and was blown away. I came to see a couple of your 'Structural' videos out of curiosity. These are just wonderful!

[DownToTheFrame]

I’ve watched three of your videos and being a content creator myself, as well as a build channel, I must say bravo! These videos are perfect educational content!

[KaceyGreen]

This was much easier to understand than the Pro-Builders I watched, I actually understand it now not just the pros and cons, and the focus on water management. Obviously both presentation styles are miles ahead of me walking past a construction site and looking over at the workers as they're there to work not teach strangers.

Great points in the conclusion, I think combining this with Solar and air exchange devices will make these very safe and economical. If planning to expand the home it seems prudent to leave provisions for that in the initial build like a wall that isn't ICF or has an oversized door/window opening that can be adapted for another use. Yes all the stuff inside will be out of date in 20-30 years why not focus on the parts that can't be easily changed (the bones).

I was also impressed with those three standing homes in that neighborhood, they looked completely unscathed, I didn't pixel peep to see how the windows and doors did, but the roofs looked fine in that quick glance too.

[perrydekryger]

We built a new home 14 years ago with all ICF exterior walls. I am sold on this type of construction with one of the greatest advantages be the comfortable living space . Living in Michigan we get some very cold days and with the thermal mass of the concrete walls you get a very consistent and comfortable living space throughout the whole house.

[martingibb]

Im a personal project builder in Toronto and finished my first all ICF two storey 3600 square foot home a few years ago. Fast, quality, and "considerably" less expensive than traditional methods, materials all around. An absolutely astounding incredibly comfortable quiet home. There will have to be a revolution in materials and processes before I consider using a different process than ICF. AND SO EASY!

[kivaunreads]

I just learned about ICF this morning, and I'm elated to see you've already done a video on it. Your videos give so many helpful visuals, in-depth info, and a light refreshing balance of humor while giving all relevant facts. Very easy and entertaining to watch.

[robertjune]

We built a 3 level, 12 classroom addition to a school using this method last year. Part of the reason it was chosen was cost. The budget was $2 million which we were able to stay on. Note: Much work, was done by volunteers such as the wired network, floor finishing, painting, and bathroom tiling. Interior walls were metal studs to allow "smurf" tubing for the AV equipment. The floors were Spancrete. The ICF part of the project went very smoothly, and it is a durable and safe building.

[grondhero]

Thanks for another educational video! I was a little kid when Typhoon Pamela hit Guam in 1976. We lived on base and had a cement home. Those cement walls really are tough!

[intheboonies]

Great video. I basically agree with all your points about pros and cons.
I would add one more pro that I only realized fully after I finished my 2000 sf home in 2013: The huge thermal mass. I live in central PA and I heat my house with a wood burner (gasifier) and radiant floor system. Even during the coldest days I only need to run my heater about every other day and just for 4- 8 hours depending on the weather. In the summer the house stays cool except for prolonged heatwaves (over 1-2 weeks). I don't have AC so a basically have no heating or cooling costs.
The house is very tight though, and if we have a lot of people together (i.e. for Christmas) during the winter, we have to open the windows to get fresh air and cool down the room we are in.
Thanks for the videos - I still have to watch more of them

[generalsnipe]

Thank you for these beautifully done and informative videos. I'm still about 6 years out from building my home. Im a tech nerd, so I am going to be running a lot of network and fiber cables to each room. I live in the upper midwest USA and think this will be a great choice for me.

[janell]

I love your vids!! You do such an amazing job. My husband and I have looked into icf, but haven’t seen something this well put together.

Keep up the great work!!

[yodaiam]

I have designed a number of ICF homes. I first used them about 25 years ago but they have more recently started to become more popular. The number one disadvantage in my mind is that if the rebar design is complex and the contractor makes a mistake, it is very difficult to fix. It is suited for simpler rebar designs. You tend to have more complex rebar designs in seismic areas and/or large windows and tall walls.

We also use it in cold climates and that has not been too much of an issue.

You can also use it just as a foundation wall. Where I am from, we usually use membranes etc on the foundation walls anyways so it is not an additional cost.

[gospelaccordingtojohn]

Great explanation Belinda. I built 2 commercial offices and three residential homes. Using a foam blocks. If you don’t have professional during the pour, you will have a blowout or worse the wall will not be plumb. Make sure who you hire for the pour has several references. It can get a little tricky, but the finished product is as advertised. And a great value since lumber has gone sky high.

[chrisgriffith]

This is a far better education on how ICF construction works than was imparted to me by my employer, 20 years ago when I was DOING ICF construction... even so- the blocks have come a long long way since then. I am going to build with this for my home, mainly for the reasons you mention, I can improve quality of the lower levels and get amazing insulation and sound proofing using ICF, and there is no reason not to use stick framing elsewhere on the build, so creative designs are only limited by ingenuity...

[CaptVimes]

As an experienced builder, I love your no nonsense, fact based research...subscribed and liked!

[morninboy]

"You can't have your typical beer guzzling lazy builders on sight" In the late 1800's carpenter were highly skilled, of high social status and well paid. Today a conscientious well heeled builder often has to compete with incompetent fools and as seen on TV everything can get built in a week or so because apparently it's easy

[benchavis]

I are adding on a 1400 sq ft ICF addition to my 1100 sq ft 135 year old home in Tucson, Arizona. Your research confirms my data on this project. Thanks.

Ben