Dallydoo: Structural Building Methods

Tuesday, January 1, 2008

Structural Building Methods - ICFs

I think the first priority in making a home work for the owner rather than the other way around is to build the home right so that it minimizes the amount of money the owner has to lay out in order to keep that home going. To the degree that the outlay of cash can be eliminated, so much the better. Probably the largest single outlay of money for most home owners is the outlay for energy costs. I know. I currently live in a home that costs WAY too much to keep comfortable. It was built in the 70's in the fine tradition of crappy spec home stick builders.

When we bought the house, it was me, my wife and a small child. The home seemed like a fine starter home for us and we were ignorant of what our options really were. Hindsight is 20-20 and if we had to do it over again, we would have saved prodigiously until we could afford to build a house that works for us instead of the abode we currently have that requires hundreds of dollars in utilities every month, not to mention the myriad maintenance requirements.

For this entry, I am going to just review construction methods I have explored and offer my opinion of what I consider is best. Beyond the stick framing that most everyone is familiar with, the industry offers a wide variety of building methods to construct a home. Even within the conventional stick framing there have been numerous improvements made recently that improve upon the age old model.

Within the model of stick framing, new methods of insulating offer a much improved home over yesteryear's offerings. There are still a number of builders that use older staid technologies, cutting corners wherever they can, rather than building to the benefit of the consumer. Given the options available, it amazes me that builders still insist on use fiberglass matting for insulation instead of some form of spray on insulation. You can Google spray foam insulation to see a number of available options, including DIY options. These are great for retro-fitting existing homes to a higher standard of insulation, however, I want to focus on methods to build the home correctly in the first place.

There are a number of energy efficient building methodologies available including geodesic, rammed earth, straw bale, ICF, SIP, and earth bermed and earth sheltered homes, as well as a number of variations on each of these. Of these technologies, the two I like the best are ICF (insulated concrete forms) and SIP (structural insulated panels). I am sure the other building methods are very energy efficient and offer their own set of benefits, but the benefit that puts ICF and SIPs over the top for me is their re-saleability. In other words, they look conventional without being conventional. If I ever needed to resell the home, I would not have to find that unique individual that would be willing to buy my unique home. ICFs and SIPs have fewer barriers of perception to overcome.

Insulated concrete forms are forms comprised of two insulating pieces of thick foam with plastic webbing between the foam pieces to keep the pieces at a consistent width apart and provide a seat for rebar placement. The forms are Lego-like and can be stacked in a staggered fashion to form walls. Concrete is poured in the cavity to form reinforced monolithic concrete walls. The foam of the forms stays in place to serve as an effective insulation. Besides providing superior energy efficiency, the houses are as air tight as they are going to get, they conserve natural resources, they offer superior noise reduction, superior protection against damaging forces of nature (including hurricanes and tornadoes), superior fire protection, and they are SOLID. If they are done right, that means less maintenance for hundreds of years, where the standard stick built home is geared to last maybe 100 years tops (with loads of maintenance). I like no maintenance. That's the home working for me. Maintenance is me working for the home.

Here are the benefits cited most frequently in the industry by ICF dealers:

Superior strength
Inherent resistance to destructive natural forces
Excellent sound attenuation
Impervious to rot, decay, and termites
High fire resistance
Energy savings of 25-70% depending on location
Consistent indoor comfort due to high thermal mass and low permeability
Structural longevity
Consistency in product and application
Maintenance-free
Architecturally "substantial" appearance due to thicker walls vs. traditional 2x4 or 2x6 construction
Negligible outgassing - no use of formaldehyde during manufacturing process

Comfort, noise reduction, strength, and energy efficiency are the four top benefits cited by owners of ICF homes. You can read more about ICFs at http://www.builderswebsource.com/techbriefs/about_icfs.htm.

Outside ease of construction, I do not know that one ICF offers much benefit over another. When I select an ICF, my primary deciding factor will probably be what my builder (or myself) is comfortable with and price. I am certain that if I had all the time in the world on my hands, I might be inclined to try and build an ICF home "myself". The Lego-like appearance of the blocks gives a deceptive impression that these would be easy to build with. While that is true to a certain extent, anyone considering this course of action is well advised to remember that you are dealing with concrete here. Your mistakes will be immortalized and as such, you cannot afford any. If you do decide to build with ICFs yourself, I would encourage you to hire an experienced supervisor to manage your crew. You will need more than just yourself at the very least when you are doing the concrete pour. It is impossible for a single person to run a pour.

The main features of an ICF form that I would look for are reversibility (the form is the same forwards, backwards, upside down and rightside up), interlocking (keeps the forms together, particularly during pours), and plastic webbing that extends far enough into the foam and creates a furring strip to which you can attach drywall and exterior siding. Here are a few of the ICF dealers that I have researched. You will not find a lot of pricing, so you may have to get a number of bids when you are ready to build.

Rewards Walls
BuildBlock
Standard ICF
SuperForm

There are other forms and I would encourage you to check them out as well. These are the ones that I have bookmarked and will most likely look at when the time comes for us to build.

Labels: ICF