From commercial pilot to general contractor (4): How I became an ICF 'Block Head'
John Bleasby had heard some negatives about using ICFs from hearsay but decided, after more in-depth research, to use them. He has found four serious advantages of using ICFs over poured concrete foundations and outlines them here. He says using ICFs was one of his best decisions.
June 18, 2014 by John Bleasby
EDITOR’S NOTE: Meet John Bleasby. John is a retired commercial pilot transitioning to life as a general contractor. Now, as he attempts to do his first solo on a new home build, north of Toronto, he has kindly offered to share his experiences with us here in a series of blogs. Veteran contractors, go easy on him – but all comments are most welcome.
If you missed John’s previous posts, here they are:
I admit it, I am a Block Head; an ICF Block Head that is. Choosing ICF construction, not only for the foundation walls of my new house but also for the main floor walls, was one of my best decisions. I had seen ICFs used in a garage/office loft project several years ago, and had heard good reports from my architect, from friends, and from my master carpenter Steve. However, not everyone was on board. In fact, the negative attitude of my original General Contractor towards ICFs was largely why I went on my own. He claimed there would be an additional cost of at least 30 per cent for ICFs versus conventional poured concrete foundation walls, and wouldn’t even touch the subject of ICFs above grade for a number of unsubstantiated reasons. Even the salesman at a local building supply store said in semi-confidence: “I know I’m supposed to sell this stuff, but I could never recommend it.”
After considering the free advice and my own research, I turned to ICFs for the following reasons.
- New standards below grade require increased insulation. ICFs give me that, plus the vapour barrier. I can apply the drywall directly to it. With a traditional concrete foundation wall, I would have had to add studs, insulation and vapour barrier; not only a material and labour factor, but a loss of internal square footage too. On the exterior, I could use the ICF manufacturer’s rubber waterproof membrane. With conventional concrete I would have had to tar and possibly add Styrofoam insulation as well. Taking the ICFs to the roof meant all the above benefits plus it eliminated both the need for external insulation and housewrap.
- Energy savings. The insulation values of ICFs are fantastic. While I’m no spring chicken, I decided that the long-term energy savings were worth it.
- Structural strength. You can’t argue against the strength of concrete walls reinforced with internal webbing and rebar!
- Fire resistance and better insurance premiums. My insurance agent told me that ICF construction, when taken to the roof as I intended, was more fire retardant and would therefore reduce my annual premiums by about 10%.
When everything was taken into account, using ICFs for my entire shell structure represented a 15% (not 30%) up-front premium: Well worth it!
Special ICF considerations:
Dealing reinforced concrete walls means ensuring all service penetrations through the foundation and main floor walls are planned in advance, BEFORE concrete is poured. The last thing anyone wants to do is bore through concrete, internal webs and rebar! HRV, Dryer vent, gas and air-conditioning, septic outlet; I listed these and many more, contacted each trade and confirmed the location and size of all required sleeves or bucks.
Next time: Mistakes will be made, but c’mon…we can do without the finger-pointing!