insulated concrete forms - a lesson in efficiency

today's lesson in eco-home building deals with insulated concrete forms.

one of the most significant building decisions we've made is the use of insulated concrete forms (icf) for our foundation as well as the common wall (basement to attic).while icf is more expensive than traditional construction methods, it results in a more energy efficient home with greater insulation (both heat and sound insulation), increased structural strength and more comfortable living spaces than conventional homes.

icf is composed of interlocking polystyrene pieces, that lock together a lot like lego blocks.

as the blocks were stacked, rebar was placed within them to provide additional flexural strength. then the forms were filled with concrete.

unlike traditional foundation construction, after the concrete cures, our forms are left in place permanently.

in conclusion, the main reasons we chose icf are:

1. higher thermal insulation - because the concrete and foam are effectively sealed together, there is greater insulation value and less air leakage in icf structures. a traditional foundation with fibreglass insulation, studs and vapor barrier typically provides an r-value somewhere in the range of r-20. we can expect an r-value of r-40 for our foundation. since we plan on using the basement for living space, not just storage, the icf foundation will make the basement much more comfortable and usable. 

2. higher acoustic insulation - we wanted to ensure that the two homes never feel like they're sharing a wall. with an icf common wall we have increased soundproofing all the way to the attic.

3. minimal waste - because of the locking block format, there was very little in the way of materials waste or overages. our icf was ordered specifically for our design and arrived straight from the manufacturer. 

4. less material and labour - drywall can be drilled directly to the icf, removing the need for insulation, studs and vapor barrier.

that ends our lesson on icf, if you find yourself still wanting more information on the icf products we used and why they're a smart environmental choice, you can do some extra credit studying here: amvic building products

stay tuned next week for a history lesson on the historic neighbourhood of bridgeland's history.