ICF home construction

[billybob123]

Looking for some (helpful) advice from CP.

My wife and I are building a new-build infill in an established neighbourhood in Calgary. We're on a relatively busy street (lots of school-time traffic and a fair bit of cut-through; some city and "local" trucks but no buses or major traffic) and we're looking to build the quietest home we can.

I also am very interested in energy efficiency, both for the potential repayment from the AB government and the savings on heating bills over the next X years we live in the house.

Does anyone on here have any experience with building or living in an ICF (concrete poured into styrofoam blocks) house? Our contractor is experienced with ICF but suggested to me that I seriously consider building with plywood with the EPIS styrofoam on the outside. This is supposed to provide the same insulating effect as the concrete walls (R values are very similar) but I'm also concerned about noise in addition to the actual insulating effect the walls have.

We're planning on getting the "best" energy efficient doors and windows we can as well.

Cost is an issue, of course, but that's not the only consideration. For the premium I've been quoted (about 3-8% of the total build cost) it's not out of reach for us. For what it's worth, we don't plan on selling the house - I realize things change, but I'm not concerned with resale value at the moment.

I want to get peoples' first-hand experience in whether it's worth it. Is it quieter than a standard stick-frame + EIPS house with good windows? Does ICF provide a better savings on heating (and how cool is the house in the summer) compared as well?

[kermitology]

I'm in the midst of doing pretty much the same thing. Our plan is to do ICF in the basement and that's it. We haven't decided on ICF for the party wall for the duplex we're building.

I've seen the SIPs (Structural Insulated Panels) stuff before and I'm not sure about it. It's all fabricated at another location (the people I talked to had it fabricated in Vancouver) and then assembled at your construction site. We discounted it on the basis of cost and the lead time.

By far the biggest energy efficiency issue is windows. I've been reading some books on that and basically it's suggested that you have as many windows as you can on the Southern exposure and try to create a heat sink in the south part of the building, main floor only, to regulate the temperature in the house. So for example, we'll likely use double pane windows in the Southern windows, and triple pane in the Northern exposure.

That doesn't necessarily answer your question, but we considered it and thought it wasn't really worth it.

Some reading: http://www.sips.org/

[billybob123]

Thanks for the reply, Kermitology. Good to know someone else is in the same boat. I've looked into SIPS; what the contractor was describing for us is a little different - build a standard stick-frame house, then put an adhesive on, stick styrofoam panels (interestingly enough built by the same company as the ICF panels, it's the same material) on the outside, then hang stucco on that.

It's really information overload for me with this!

The south-facing issue is a good point too - our house is south-facing, so the big windows will probably be that direction anyway. I don't want my house to bake in the summer though!

[You Need a Thneed]

My dad (Gold Seal Certified estimator) has done calculations in the past, you can form and pour a concrete wall, then clad it with insulation on both sides for cheaper than buying the ICF blocks. You basically end up with exactly the same thing, probably even better insulation.

ICF blocks are a more expensive way of doing the same thing.

Let's put it this way, there's a reason why virtually no contractors do them - there are cheaper ways to achieve the same benefit.

[kermitology]

Originally Posted by billybob123

The south-facing issue is a good point too - our house is south-facing, so the big windows will probably be that direction anyway. I don't want my house to bake in the summer though!

The tip for that part is to provide an overhang over the main floor south windows such that in the winter, the sun shines through, but in the summer when the sun is higher in the sky it doesn't.

[moncton golden flames]

as a home designer, i have some experience with these products.

typical construction method: concrete foundation with wood stud walls and stick framed roof. this method is the most cost 'efficient' in the short term. but over the long term, your utility bills will offset any saving you had up front. most homes in calgary are built this way.

external insulated finishing system (eifs): this system is starting to be rejected by engineers. something about how the external rigid insulation is attached to the building, is starting to compromise the building envelope and hence may have vapour/moisture issues. it's a great retro-fit solution for older homes wanting to beef up insulation, but for a new build, i would steer clear as it's an inferior technique for efficient new construction.

structural insulated panel (sips): the great advantage to sips panels are that they have no thermal bridging between inside and out, like a typical wood stud wall has. this makes sips a more energy efficient system. sips also has roughly the same wall thickness as wood stud, which means you won't need special depth windows to span the wall thickness. sips can be a pain when you look at electrical and plumbing. you can't simple run your electrical or plumbing down thru the exterior walls. for electrical, you must cut out channels to run the wires thru. sips allow zero forgiveness in window placement, as the holes for windows are already pre-cut before arriving on site for assembly. so make sure you are 100% confident that the windows are located exactly where you want them.

insulated concrete foundation (icf): this product comes in many core widths, starting at 6.25" and 8" being the most common. tack on to those, a 2.75" layer of styrofoam on each side, and you have yourself a thick wall with no thermal bridging. the windows will need refelct the thickness of your walls and may cost you more. electrical voids are hotknived out of the styrofoam where the wires can be run. icf does give you the largest r-value as well as a great stc rating if you worry about noise levels.

there is no perfect way to build a home, but there certainly are wrong ways to do it. the wrong way would be to combine some of these elements to say you used them, instead of using them properly in their entirety. an example of the wrong way to build a homes would be to use an icf foundation, typical wood stud walls with eifs and a sip roof. keep the build simple and consistent.

if i had my choice to build a new home today, i'd be building a strawbale home, but that's for another discussion......

[topfiverecords]

Some additional products that are being contemplated for a new build I'm working on. Forms made of wood fiber instead of foam/polystyrene.
http://faswall.com/
http://www.durisolbuild.com/

[mots]

I think you are better off putting money into better/triple pane windows. The styrofoam under acrylic stucco as opposed to stucco wire is great until one of your kids is playing hockey or basebell and it goes through the stucco as its so fragile.

[moncton golden flames]

Originally Posted by topfiverecords

Some additional products that are being contemplated for a new build I'm working on. Forms made of wood fiber instead of foam/polystyrene.
http://faswall.com/
http://www.durisolbuild.com/

i've never seen this product, thanks for this!