A brief update because it's been a while:
1) I've now personally moved over 40 tons of gravel...which feels like it sounds. My hands are kinda messed up and I'll need to have one of my fingers looked at sometime when I have a second because the finger keeps locking (never good!). Anyhow - after something near $4000 worth of gravel, the slab is finally set (as well as the draintile). Can't say I budgeted for that!
2) Continuing along the lines of the foundation, I've now laid down roughly 10-12" of gravel (don't ask), which is more than is needed, but will at least give a nice capillary break. After a fair bit of research, I've come to some other conclusions including:
- the layering should go (from bottom to top): compacted soil, 3/4 clear crush gravel (at least 4"), insulation (more on that in a second), then vapoour barrier, then mesh (with PEX zip strapped to it), then concrete slab (32 MPA minimum).
- Type II EPS and Type IV EPS (known as XPS) is an interesting debate. Most people use EPS, which is baiscally compressed styrofoam. It isn't as strong (compression strength), doesn't have as high an R-value per inch, is less moisture resistant, and more appealing to termites compared to XPS. EPS, however, is cheaper and better for the environment. In the end, I went for XPS because the thought of having a slab that runs into major issues makes me want to put a gun to my head. It was $900 extra for peace of mind. We'll use 4" for a slab insulation value of R-20, which is R-8 above code (in Vancouver = R20). From the sounds of things however, it would appear that Vancouver will soon move to a slab R-value of 20 which I find kinda surprising (more on that in a second as well).
3) I'm pretty surprised actually at how green the Vancouver building code is. It is actually (apparently) the greenest building code in all of North America - kinda surprising for a climate that is as mild as Vancouver's! It requires an R-40 attic, R-22 walls, R-12 slab, an HRV, to be plumbed to be solar-ready, rainscreens (which make a lot of sense given our climate), and a bunch of other things. Furthermore, they're actually in the process of making it even stricter (R-50 attic, R4 windows (= U 0.25 which is pretty high), R22 EFFECTIVE walls - which means that you have to factor in the fact that where the 2x6 studs run you have R-6 hit...in other words, your walls probably need to be a nominal R-26 or so to get to R-22 effective), a tightness of 3 ACH, and a slab of R-20.
Now the thing that gets me is that if you break down how much heat is lost by different parts of a house, it roughly breaks down as follows (from all that I've learned):
Attic = 25%: To get to R-50 in the attic is cheap (probably about $1500 or so for a place like ours)
Walls = 35%: To get to R-22 effective is pricey...cheapest route is a double stud wall with blown cellulose which is probably about $4-5000, but eats up a huge amount of space. Our approach will probably cost about $6000.
Slab = 15%: To get to R-20, you'd need either 5 inches of EPS ($1800) or 4 inches of XPS ($2700)
Windows = 10%: To bump up from double to triple glazed is actually quite cheap (R3 to R5 bump) - somewhere around $50-150 per window.
Air leakage = 15%: Now 3 ACH (or air changes per hour at 50 pascals) is a decent standard for air leakage but FAR from where Vancouver should really be heading. My thinking would be that they should be targeting an ACH value of about 1 if they're really wanting to "push the envelope" (har har). Passive houses (which require values not far from what the Vancouver building code will soon be) require roughly R40 walls, R60 attics, R6 windows, BUT an ACH value of less than 0.6 (often down around 0.3-0.5) = nearly airtight. So I'm kinda surprised that they're not wanting to make the houses more airtight especially given that an HRV is already a mandatory thing in Vancouver. We'll be aiming for an ACH of less than 1, and I'm using a combination of Prosoco's RGuard CAT5 product and (I hate to say) some spray foam to get at the areas that are problematic to seal. This will probably cost me about $6000 in the end (for a total insulation and air sealing cost of about $17,500 versus a standard house that would run about $8000 in Vancouver). I'll likely never pay that back (even a simple payback is over 15 years by rough calculations), but I do expect that my heating load (and CO2 emissions) will be about 75% less than the average house (ignoring life cycle assessments).
So why do it?
Comfort. That's the number one reason that people have gravitated towards passive building...they're comfortable to live in year round...no weird cold patches...no drafts...healthier...better for the environment, etc. etc. - there are a lot of reasons, but probably health and comfort trump the rest.
4) The framing continues to move along with the lower level basically done and the upper level starting this week, which is exciting. The downside is that the main floor is pretty dark (no side windows). I had been hoping that the big front and rear window assemblies would make up for this, but it seems I was ambitious in that thinking. While there will be more light when the drywall and paint go in (white), as well as the ceiling (white) and polished floors (concrete) and cabinets (high gloss white), I still fear it will be dark. So what are our options:
a) Leave it as is: could do...but....don't really like darkness and feeling like we're living in a dark cavern. Not really an option.
b) Install a solatube: Costly $800, inefficient (R3 hole in the roof), but does add light that would brighten up about 250 sq.ft. in the kitchen.
c) Add back in windows that were originally in the house: One of the FEW bonuses of doing a renovation is that you can usually retain windows that were existing. Accordingly, we're hoping that City Hall might allow us to retain one additional window on the east wall and one on the west wall. This would add a lot of light and thought it would require re-working the kitchen design, we both agree it would be worth it. So....we've taken our plans to City Hall and will explore whether it is possible....stay tuned, we'll find out next Tuesday. Hopefully it won't delay the schedule by much...possibly a little bit, but I'm hoping I can work around it for the most part since the exterior and interior will soon be on separate paths and 95% of the windows can go in soon (next week at the earliest).
So - plan is to go for (c) with a backup of (b).
A few shots of the progress...and having looked through them, a lot has happened in the last while!
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June 17th - view of cribbing with the walls in place |
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June 18th - our new sewage and water lines being inserted with a torn up East 6th Ave. |
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Yay draintile! Which fell during a very wet (and muddy) period unfortunately (taken June 23) |
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Gravel and delta drain falling into place (lots of gravel, round 2) |
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Cribbing being removed and the house lowered back down...well, at least lowered back down on the east side! (taken June 28th) |
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Strongwalls in place and parallam starting to go in |
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Parallam and all lower framing complete (as well as a 2" gravel layer in the slab area). Taken July 13th |
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An additional 7-9" of gravel being added on July 14th. |