ICF vs Conventional Concrete

 

ICF vs Conventional

Hi guys! Here we are already getting to the fun stuff! Lots of you might be wondering when building your home “what’s the deal with this ICF?”. There’s lots of info on ICF and the technology used in keeping basements warm and dry. Provided you know where to look. And we like to think that if you’re looking at our page, you know where to look!

The first ICF (Insulated Concrete Form) was patented in 1967 in North America. Patented by a Canadian by the name of Werner Gregori he took the idea of a styrofoam drink cooler to the residential and commercial market.

ICF is a system of formwork for a reinforced concrete wall made with rigid thermal insulation (usually expanded polystyrene insulation, but lately there have been more insulation methods used) on either side, tied together with plastic webs usually at eight inches on centre. These ribs provide the backing for drywall and other cladding attachments. The forms themselves typically stack like lego blocks and allow for a simple set-up as their tops and bottoms and lately usually sides as well have an interlocking design.

Like every system there are advantages and disadvantages. Even within the ICF field there are many different competitors that offer different construction methods to either save material or labour costs. Below are the disadvantages of ICF:

  • Difficult to visually inspect the concrete pour. Traditional concrete walls are easy to inspect/patch (if needed) once the formwork is taken off. Very seldom is patching needed for structural concerns.
  • Up-front cost. If you build with Dueck Homes this isn’t true as our spec for traditional walls involves spray foam to combat mold issues. Most new houses today however have a 2×4 frost wall with fibreglass insulation on the inside and that is a slightly cheaper option.
  • Burnability till covered. Because most ICF’s are made from Expanded Polystyrene Styrofoam they lend themselves to being pretty flammable. Cutting rebar or welding around ICF must be done with caution as it should be on any building site anyhow. Once covered with drywall though there is no more concern than a frost wall for flammability.

While the disadvantages may seem scary when listed, we haven’t found them to be an issue on our job sites when precautions like proper consolidation (vibration) has taken place. Once you know how to work with your product you can mitigate a lot of potential issues. Here are the advantages of ICF

  • Energy Efficiency. Huge advantage here. Building with ICF includes solid air barriers, high thermal mass and minimal thermal bridging. That’s fancy talk to say that cold doesn’t get conducted through the wall easily, and because the concrete is sandwiched between two layers of insulation, it takes a long time for the wall to change temperatures. This means your basement temperature has a much easier time staying consistent!
  • No mold/mildew. Because the styrofoam on either side of concrete isolates the water/moisture, you wind up with a dryer basement. You’ll have healthier air quality and much less chance of mold. Recently we removed the standard frost wall insulation and noticed that many of the batts were moist, some were soaking wet. Other basement’s with traditional style frost walls we’ve found an inch of ice built up on the wall. ICF will not allow moisture to build up on the styrofoam face thus meaning no mold/mildew issues in your basement.
  • Stronger walls. Because ICF is an insulated form that the concrete stays in, the concrete is allowed more time to cure. You can pour concrete walls with less effort in fall/winter because it’s blanketed by its own insulation. The hydration effect from the concrete will keep it warm, allowing it to cure longer. The longer it cures the stronger it will get.
  • Sound absorption. Building with ICF gets you a quieter home. Because you have sound-killing insulation on both sides of a solid concrete wall you will have a quieter basement. This is something to consider especially when you’re building in high traffic areas or considering building an entire house out of ICF.

I hope this quick breakdown has given you some things to consider as you look to build your house. We’ve built a few houses now with ICF to the rafters so we have a fair amount of experience both designing mechanicals and wall systems as well as the building. If you have any questions please ask either in the blog sections or find us on Facebook and ask there! I’ve attached a few pictures below from some of our builds.

 

Shalom!

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3 thoughts on “ICF vs Conventional Concrete

  1. Hi Guys,

    Great, post!

    I can appreciate all of the benefits of ICF, however, I am interested to hear any thoughts on the issue of disposing of an ICF assembly at its eventual end of life. Traditional concrete can be broken down to concrete and metal reinforcement bars and recycled/reused however I can’t really picture the same happening with ICF. I look forward to any thoughts!

    Keep up the great work.

    Eric

    Like

    1. Hi Eric,

      That’s a fantastic question! I have a few initial thoughts but will see if I can flush out a few more from wiser people than myself.

      1) ICF is often made from recycled materials (ie recycled plastic for webbing, some plants are taking crushed eps blocks back to reuse that insulation). So in that sense, it starts off being a recycled product.
      2) I would argue that in order to do a proper traditional concrete wall you’ll need outboard insulation that will have been glued to the concrete on the outside, then on the inside my argument would be for spray foam but even if you use fibreglass insulation (which is likely wet and moldy after 50-100 year life cycle) you’ll still wind up likely throwing that out.
      3) I’m assuming the questions is one of reducing carbon footprint and reducing waste? I would be interested in a study comparing the reduction of carbon footprint by using less energy to heat/cool your house even if at the end of the ICF life-cycle the styrofoam on the outsides is considered waste.
      4) Traditional concrete may be able to be broken down and re-used, but seldom is it. Often it’s crushed as much as possible, then hauled to a land-fill.

      And now for a completely pie in the sky thought. Perhaps at the end of the ICF lifecycle, it will be cut into slabs and have a use in that sense as an insulated structural unit.

      Thank you again for your posts. Great ideas are born through community discussions. Looking to keep bettering ourselves through these conversations. Thanks Eric,

      Josh

      Liked by 1 person

    2. Hi Eric,
      In follow up I went to pose your question to AMC Foam in Headingley. Very helpful folk out there.
      Before they began recycling broken blocks and cut off eps they actually had requests to ship the eps to be used as clean fill to mix with heavy soils. Recycled ICF will be less harmful to the environment than the traditional framing materials (not including wood, things like poly, rubberized tapes, caulking, glues, fibregless, formaldehyde used in pressboards, OSB, Plywood etc). So considering that traditional framing will be replaced many times before concrete it seems greener in that long run sense as well.
      Your question spurred a lot of thinking, thank you!

      Like

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