Whether you’re a home or building owner or an installer, there are pros and cons of insulated concrete forms (ICFs), just like any other building material out there. And while ICFs are on the rise (especially as the advantages over wood-framed homes come to light), it’s still important to look at a balanced perspective.
Pros And Cons of ICFs for Home/Building Owners
Homeowners benefit from:
Home and building owners also benefit from ease of construction just like installers, but there are a number of additional advantages as well.
Homeowners benefit from enhanced energy efficiency — the general consensus is that ICF homes require 32% less energy to cool and 44% less energy to heat and have an effective R-value of anywhere between R-20 and R-28 for the entire life cycle of the home. In fact, they are a major contributor to achieving net zero compliance.
The problem with wood-frame homes is that they have insulation gaps and thermal bridging, resulting in energy loss. ICFs are so airtight that leaks simply don’t occur. In fact, this groundbreaking study (which we like to cite quite a bit on this blog!) found that an ICF wall had 60% less energy loss than a wood-framed wall.
Another major advantage of ICFs is their thermal mass, absorbing heat during the day and then circulating the energy back into the house as temperature drops at night. This results in a much more stable (and comfortable) temperature throughout the home.
- Extremely Resistant To High Winds And Climactic Events
Next to their energy efficiency, ICF homes are extremely wind-resistant due to the strength of the concrete. This is why there’s an increasing number of homeowners who are choosing to build with ICFs in hurricane-prone areas, just as you can see here. In fact, ICF homes are entirely disaster-resilient and even have a 4-hour fire rating.
As proof of their durability, a laboratory study conducted by the Wind Science and Engineering Research Center at Texas Tech University found that ICF walls were “far superior” to both conventional wood and steel framed walls in conditions simulating a tornado.
Indeed, Logix’s ICF walls are capable of withstanding winds up to 300mph.
The combination of the foam and the concrete, which acts as a sound barrier, results in a very quiet home. Logix ICFs, for instance, have a sound transmission class of 56, which is twice as much as a standard wood-framed wall.
That’s exactly why the Souris Hotel in Manitoba (shown below) was built with Logix ICFs (read more about the build here).
The effect? Almost no outdoor sounds and a quiet, comfortable home.
- Mold and Mildew Resistant
Finally, ICF homes are also mold and mildew resistant. Part of this has to do with the fact that the building envelope is airtight, therein providing a level of moisture control.
In contrast, a traditional build with house wrap results in a build-up of moisture. ICFs allow walls to breathe and prevent mold and mildew from growing.
And as for the cons…
- A Possible Lack of ICF-Friendly Builders, Architects and Engineers
Depending on where you are building there is can be a lack of builders, architects and engineers who specialize in ICFs, which can make them reluctant to want to choose ICFs due to their lack of experience.
However, this will continue to change as ICFs continue to become more and more popular.
Here is a free directory, ICF Pro-Link, to locate installers, engineers and architects who have worked with ICFs.
- ICF Walls Are Thicker = Reduced Overall Interior Space Dimensions)
ICF walls are thicker; and while this creates a very desirable window well effect, it also can reduce the overall interior space dimensions as well.
- Slighter Higher Upfront Costs
The initial cost of ICFs can sometimes be slightly higher than framed construction, but with an experienced ICF builder, and depending on the nature of the structure being built, this isn’t necessarily the case. Additionally, when it comes to cost, an air exchange system in an air tight ICF home isn’t optional.
- Future Additions Can Be Challenging
Finally, future additions and/or renovations can be a little more challenging with steel-reinforced concrete walls as compared to wood-framed buildings.
Pros And Cons for Installers
Installers benefit from:
First and foremost, installers benefit from a much easier build compared to wood. This is true even in winter conditions. Construction steps are condensed into just six simple steps, eliminating steps like house wrap. Put another way, many different building components are rolled into one product. The blocks then stack together like lego.
ICFs typically require less trades and therefore less coordination of trades, contributing to faster builds just as you will see below.
Installers will tend to see fewer callbacks due to water penetration in foundations as well as ICF foundations are fully waterproofed.
- Speed of Construction
An easy build results in a much more efficient build as well.
If you are a regular reader of the Logix ICF blog, you’ll have heard about what happened when General Contractor Harvey Schellenberg built two identical buildings (one ICF and one made of wood) beside each other.
The ICF build was completed much faster, with the only taking 12,000 hours compared to 18,000 with wood.
Again, part of the speed comes from the fact that only one trade is needed as well as the fact that you don’t need to sub out the basement (and the fact that callbacks are greatly reduced). There is also no need for house wrap.
Even in winter conditions, you don’t need to install exterior cladding; once the building is enclosed, interior work can be done.
Once the building is ready to be inspected by the building official, installers will also see fewer inspections as there framing and insulation inspections are eliminated.
And as for the cons…
- More Advanced Planning Is Needed
More advanced planning is needed at a couple of different stages of the ICF build. For instance, in order to determine lintel requirements, you must first determine loads.
Similarly, post concrete pour changes and service penetration locations can be difficult without the right equipment on hand, so advanced planning is recommended.
- A Possible Lack of ICF-Friendly Installers
While ICFs are growing in popularity, in some areas there can still be a lack of ICF-friendly installers (as well as electricians, plumbers, HVAC companies, framers and local building officials with ICF knowledge).
- Certain Practices Must be Adhered To
With ICFs, certain practices must be adhered to. Here are three primary examples:
- Proper concrete consolidation practices (due to the fact that voids in ICF walls are not obvious and visible).
- Below-grade waterproofing membrane (but not for conventional concrete forming to which damp-proofing can be applied).
- The exposed section of a wall between finished grade and cladding must be parged.
- Screws Are Used for Cladding Attachments
On the whole, ICFs save builders time and money compared to wood. However, that’s not to say that ICFs are without added labor and costs throughout the build. Since screws are used for cladding attachments instead of nails, builders will see added labor and material cost.
Wrapping It Up
While there are pros and cons to every building material, there is a reason why ICFs are becoming so popular for installers and homeowners alike.
From ease and speed of construction to energy efficiency, disaster-resilience and comfort, this is all part of the reason why.
Lastly, while there’s a lack of ICF builders, engineers, plumbers, etc. this will continue to change in the future.
Read more about the advantages of ICFs here.