Sorry to all for the delay on postings...it's just going to be like that sometimes...but what I will say is that I will always return and post in the end!
So a brief update on a bunch of things and then some gory details on insulation. In general, things are with BCA right now as they update design documents and get things ready to go to permitting with the City of Vancouver. Accordingly, not much to report in terms of design (except for the fact that I've been fiddling around with a few internal, 3D programs ranging from Ikea's kitchen planner (which seems to constantly crash my computer as a warning) to a relatively nifty one I found the other day while poking around on YouTube called Homestyler. I've also been doing a ton of research into wall assemblies (wall design/composition in simple terms), insulation, and a little bit on foundations/draintile and excavations...oh, and soil remediation. I've had quotes for a bunch of demolition/hazmat removal (will get to hazmat stuff in another posting), as well as a few quotes for insulation thus far. That and I need to start thinking about plants and shifting vegetation if possible. And that's the general update of things.
More specifically: insulation. What kind to use?
Options and thoughts:
1) Fiberglass (loose fill/batt)
Basically fiberglass is spun chunks of glass...it's what we all grew up with.
Upside is that it's cheap, it is relatively heat resistant (doesn't melt until a few hundred degrees), and it offers pretty good "bang for your buck".
Downsides are that it's an irritant to the skin (etc), it's not super environmentally friendly all-around, and it doesn't offer large R values. It can also droop in the wall cavity and is totally ineffective if not properly installed.
Cost: To give you a sense of cost to R-value (effective "warming" value), Home Depot offers this: Owens-Corning EcoTouch R12 (3.5") for 2x4 studs (which equals an R of 3.42/in.) for about $64 for 150 sq.ft. ( = $0.42/R3.42/sq.ft.). To put this into perspective, to insulate the proposed full house to R20 walls, would roughly cost $850 + HST.
2) Cellulose (loose fill/wet spray)
Basically chopped up (recycled) newspaper plus a non-toxic mold/insect/rodent repellent/fire retardant (borate).
Upsides are that it's also cheap, and offers very good bang-for-your buck, and is environmentally friendly. Downsides are that it's less flame resistant, can also sag in the wall cavity and can create a fair bit of dust. Cost wise it's about the same as fiberglass , but takes up a little bit less space if done via wet-spray (so more R-value can go into the same space).
Cost: An R-value of about 3.5/inch is reasonable, with a rough cost of about $0.50/sq.ft. or, for R20 walls and an R60 attic in our place, about $2200 + HST.
3) Foam (soy-based/standard/cementitious)
Foam is the touted "wonder solution" of the insulation world. Not only does it (largely) form a vapour barrier, it has a relatively higher R-value to inch ration (around R4-6/inch) and can be sprayed into all sorts of spaces. While relatively expensive, it is the choice of many people (including Mike Holmes!) because of the fact that it seals in air while giving a high R-value, thus delivering a 2-in-1 value. Furthermore, there are a bunch of types of foam (see this for a more complete list): more "environmentally friendly" soy versions that are non toxic; standard (and toxic) Icynene foams that are made up of who-knows-what (can contain VOCs and produces poisonous gases when burned); and lastly cementitious foam (commonly called AirKrete) which is magnesium oxide and cermaic talc. Unlike a bunch of other foams, it doesn't do the crazy (expand in a nano second thing) but rather comes out like shaving cream and then hardens over 24 hours. Each one has its own pluses and minuses but in general...
Upsides: Vapour barrier, fits into many spaces, dense R-value for tight spaces (can get upwards of 24 into a 2x4 studded wall), mostly environmentally benign.
Downsides: Poisonous when it burns, though fire retardant it often has a low melting point (note: both of these are not true for cementitious foam - but it has the downside of being more fragile at lower densities), expensive, and not easily removed (therefore does not permit deconstruction). Some types of foam also produce nasty chemicals when created (e.g., CFCs, etc.)
Costs: Rough quotes for something like BASF Walltite Eco Foam are about $4/sq.ft. (R5, but includes a vapour barrier that makes the effective R value better overall). This means that quotes for R30 walls + R55 attic come out to about $11-12K + HST.
4) Rockwool (loose fill/batt/rigid)
Rockwool (which in Canada is sold under the brand Roxul) is a mineral wool composite basically made up of 75% recycled slag (steel) and 25% basalt. The products are heated to very high temperatures (1600 degrees C) and then spun into various forms.
Upsides: Decent R value (~R4/inch), extremely fire resistant, quite sound resistant, moisture/insect/vermin resistant, comes in various forms (some of which can be applied to the outside).
Downsides: Moderately expensive; not easily available; quite heavy; high initial carbon footprint (embedded energy). Furthermore, while not noted as carcinogenic, early forms were harmful and other forms used to be classed as dangerous. More recently, non-human-available forms have been downgraded in their danger, but are still known to be irritants (like fiberglass).
Costs: Costs vary for the different forms (batt vs. hard), but come out a bit more expensive than fiberglass for the batting ($0.60/inch at R4) and I've had a rough estimate of about $1.15/inch at R4 for the hard (IS form). Combined, these would give a wall assembly of R38 and an attic of R58 (via Comfortbatt) for a total of about $6,100 + HST.
5) Natural wool (Sheep/Cotton)
Of late there has been an increased push to generate more natural forms of insulation. Accordingly, more traditional fibers such as wool and cotton have started entering the game. Sheeps wool, long used to insulate...well...sheep (and people from New Zealand, Wales, etc.) has made a resurgence, as has recycled denim jeans (cotton).
Upsides: Good sound absorption and decent R-value (just less than 4/inch), very little embedded energy and contains a large percentage of recycled materials (>85%), not dangerous in the least and can be handed without any protection safely. All things said and done, it's probably the most environmentally friendly insulation form of those listed here.
Downsides: Not easily available (though it is sold in BC - Bonded Logic - by Twin Maple Marketing in Abbotsford), not as cheap as some other forms of insulation, could be susceptible to moisture/mold issues and not as fire retardant as most other materials (though it does indicate protection from all of those things). It's also heavier than some other forms of insulation.
Cost: Roughly $65 for 84 sq.ft. for 3.5" (R13) (or $0.76/sq.ft), which means about $4,500 if I were to put in R24 walls along with an additional $2,300 for an R65 attic space.
6) Polystyrene/Structural Insulated Panels (hard foam)
While technically this is really another form of "foam", it's a bit different for several reasons. While polystyrene panels can (and do) exist on their own, I was keen to look into SIPs (or Structural Insulated Panels). These are basically a giant, pre-assembled walls made up of a big chunk of polystyrene sandwiched between two MDF boards (combined with a few other odds and ends). The cool thing about SIPs is that they're precision cut off-site and then just brought in and assembled directly from a crane. Accordingly, there's little was and assembly time is super fast (no framing). They're often used as a manner of doing "pre-fab" and have shown useful especially for modern housing design (especially in remote areas).
Upsides: High R-values (40+ possible), fast to assemble, little waste
Downsides: No cheaper than other forms, must have plumb surfaces, some quality/performance issues have emerged as the technology improves.
So - with all of that, here's what I've concluded so far:
1) SIPs aren't very suitable for a renovation (non-plumb foundation = nightmare)
2) Fiberglass, while cheap, weirds me out.
3) Cellulose is an option for the attic, but settling eliminates it as an option for the walls.
4) Rock wool is an interesting option, but the batt stuff kind of weirds me out (like fiberglass). That said, I'm pretty keen on the hard form on the outside...so it's still in the running.
5) I like the fact that spray foam creates an air seal, but I'm hoping I can do this in other means and avoid using it. It's expensive, and I don't like the fact that it eliminates deconstruction options in the future.
6) I'm pretty down with using the denim batts in the attic if I can because it makes it safe for us to go up there in the future (plus allow us to access it for potential "deep storage").
In summary, at the moment I'm thinking I'll probably go for a double layer of the Roxul ComfortBoard IS (rigid rock wool) on the exterior (giving me R24), along with either ComfortBatt (R14) or Ultratouch Denim (R13) on the interior walls. For the attic, I'll probably either do wet spray cellulose (super cost effective, but makes the attic dusty) to R60 or more Ultratouch Denim (to around R60). This provides a bunch of advantages - including minimizing thermal bridging, allowing me to maximize internal space, having a very warm/fireproof/soundproof house, while keeping costs somewhat lower.
The fronts and backs of the house will still be a bit cool (too much glass!), but such is life...we're trading off some heat for sunlight and views...
A few websites:
http://insulation.sustainablesources.com/
www.roxul.com/residential/products
www.smartlivingdirect.com
www.greenbuildingadvisor.com/green-basics/spray-foam-insulation-open-and-closed-cell
sprayinsulationbc.com
www.stocorp.com
And last but not least before I sign off for the night (will need to come back and finish up a few of the cost details), congrats to Vancouver for keeping Gregor in for another few years...looking forward to seeing what happens re: Greenest City. Yay to bike lanes and chickens!
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