Passive open-concept family home in Climate Zone 8 – Ontario
Hi All
I just finished binge listening to some finehomebuilding podcasts and heard the 2 with Martin in and thoroughly enjoyed listening. We would live in US Zone 8 being 45 minutes north of Grand Portage, MN.
Degree Day Rating (18C / 64F) 5673
I am looking to build the best family home I can next year with a budget of around C$400k. It’s on 30 acres with well and hydro already in place. Looking to have maximum Southern exposure for passive heating and spend the money more on materials than labour. I am hoping to labour as much as I can around shift work as well as maybe do the electrical and PEX plumbing to save costs. I am a qualified UK electrician and it seems fairly straightforward with some subtle differences.
So my plan at the moment, with a PH architect doing the building drawings etc, is:
FPSF floating slab foundation R44 [Isoslab’s 16″ kit]
SIP exterior walls R38 [Thermapan from Toronto area]
Triple glazed Tilt & Turn windows [Geneo uPVC Access windows Winnipeg]
Slate effect Metal Roofing [Wakefield Bridge – English Slate]
Insulated PVC Siding [Cedraboards XL]
Zehnder Comfoair 550 HRV with pre heat [Small Planet Supply]
AO Smith 66G Hybrid HW tank
Zero clearance see-through wood fireplace [Supreme Duet]
Colour & polish the concrete slab for a finished floor.
Majority of the windows on the Southern side for passive heat with relevant overhangs to prevent summer overheating.
Thinking SIP walls due to limited building season, starting in June 2018 to guarantee slab has best chance to prevent cracking etc as it’s our finished floor, reduce waste and labour/framing costs.
‘False’ 2×4 framing for all interior walls to allow majority of plumbing and electrical to be stapled to the inside of the SIP panels. (My thinking is it will cut down on labour to drill alot of the studs and reduce any protrusions etc in the SIP which will be taped internally)
Open web trusses to allow easy installation of remainder of utilities between floors.
Raised heel roof trusses on top of a sealed ceiling filled with cellulose.
Wood fireplace will have a fresh air kit to help with sealing remainder of the structure. It’s there mostly for aesthetics (clad in culture river rock) and an emergency heat source.
Gas Range – because my wife wants one! and electric outages.
Also thinking;
Gace Vycor eN-VS as house wrap with a rainscreen under the insulated siding
Vycor flashing for all doors and windows
Grace Ice & Water shield HT for rooof
So am I crazy and living in dreamland?
Where do you see any major errors and suggestions…
Thank you, thank you, thank you 🙂
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Replies
Kiefk,
It sounds as if you think that a materials list makes for a good house.
But building a good house has very little to do with choosing brand names or specific appliances. It has to do with a conscientious approach that focuses on air sealing. Having the materials installed carefully matters more than the brand name.
Some specific feedback:
1. I don't recommend insulated vinyl siding. The best aspect of vinyl siding is that it has an irregular profile that provides a built-in ventilation channel between the siding and the water-resistive barrier (WRB). With insulated vinyl siding, this air channel is filled with foam insulation, creating a smooth consistent back surface. This removes the natural ventilation channel.
A wood-burning fireplace introduces a deliberate thermal bridge (the chimney) and a hard-to-seal air leakage path. Every time you light a fire, you'll have to worry about whether the combustion air source is working. So scrap the wood-burning fireplace.
A gas range introduces pollution into your kitchen every time you cook. I suggest that you look into induction cooktops.
Kiefk,
You don't say how much house you are attempting to create for $400K. If you are attempting to build something around 2,000 square feet, I would suggest targeting a "pretty good" house level of performance. With this approach, you can probably include some solar voltaic on your build and maybe even reach net-zero performance (assuming you have the right site conditions, of course).
GBA has many articles and discussion threads on this topic.
Thanks Martin & Steve
Our current floor plan is 57x36 ground floor and 57x28 upper floor.
Martin, would you elect for a double stud wall over SIPs. You seemed in the podcast to not be a fan? I thought costs/end results would be comparable but build time quicker with less waste using the SIPs.
Regards the fireplace, I hear what you're saying but it is the focal point of the open concept home. Also I am required by code here to have a source of heat which the Zehnder unit will not qualify as...don't really want to put in a couple of baseboard electric heaters just to tick a box.
The induction cook top we did have as an option B for the kitchen but the wife seems adamant she'd prefer a range, maybe something I can work on? I read on another 'future resistant' project where they elected for induction cook top and built in ovens because as they got older they'd be less reaching down and into a range oven. Seems petty now but could be a real back saver later on.
Floor plan works out at 2052 sqft and I think I'd be more than happy with Net Zero. Both my mortgage and mortgage insurance would give me rebates if I hit above Energy Star level. I'm hoping to rough wire in for a standby generator and PV for the future.
My mantra, it seems, will be attention to detail and air sealing. I put brand names etc down just so people could see the kind of materials we were thinking of, rather than leaving out info for people to guess.
I've attached our floor plan (Copyright: Gammond Architectural Technology)
thanks both of you
Kiefk: you need a heating source in zone 8 besides the fireplace.
I've said this before. Buy a cheap induction single burner unit for about $50. Try it out. Induction is more efficient and quicker and as responsive as gas. And you avoid dumping lots of CO2 And water vapor into your kitchen.
We located a wall oven with the bottom of the unit about 28" above the floor. It's much easier to access heavy items than with the typical range.
Kiefk,
Your plans include somewhere around 3300 sf of finished space. Given your budget of $400k, that works out to $120 a sq ft. I don't know what the average construction costs are where you are building, but that's the first thing you should probably find out. A code compliant house here is in the range closer to $200. The increase in costs moving to something "pretty good" in terms of levels of energy efficiency will typically be somewhere around 15%. I don't want to discourage you in any way, but the most common cause of problems among DIY builders is underestimating the costs of their project. Going in with a realistic budget sets the stage for everything else. Good luck with your project.
For clarity's sake, unless you're traveling at mach-III in a supersonic jet, 45 minutes north of Grand Portage MN would still be US climate zone 7. At a reported 5673 HDD18C you're still on the warm side of zone 7. Zone 7 starts at 5000+ HDD18C, Zone 8 starts at 7000+ HDD18C.
https://www.greenbuildingadvisor.com/sites/default/files/images/Table%20301.3%282%29_0.preview.jpg
Even Moosonee on the southern shore of Hudson Bay is still zone 7, but the cool edge, at a bit fewer than 7000 HDD18C for a 25 year average, with only the occasional year where it breaks 7K.
https://moosonee.weatherstats.ca/charts/hdd-yearly.html
Thanks Malcolm
I was hoping that by doing some labour, the electrics and supply plumbing as well as leaving some finishing (painting and tiling) I’d be able to make the budget work. It’s why I’ve been trying to find a simple efficient way to construct the home. Limited plumbing runs, utilities in existing voids etc. I will try and get the contractor I sub to into fixed priced work rather than hourly.
Dana
I obviously wrongly assumed zone 8 from the zone map on the website which had 7/8 for Minnesota...
Kiefk,
I'll reproduce the climate zone map below. Northern Minnesota is in Zone 7.
You're right that the Zehnder HRV is a ventilation appliance, not a space heating appliance.
Stephen is right: Code officials will not consider a wood-burning fireplace to meet the requirement that a home needs a way to keep the space heated during the winter. You'll need a furnace, boiler, heat pump, or electric-resistance heaters to satisfy code requirements for space heating.
.
Kiefk,
Every builder who has looked into the issue has concluded that SIP walls are expensive compared to other alternatives. If you schedule is tight, and you want your walls to go up fast, you may be willing to pay the premium required for SIP walls. The decision is yours.
For more information on this issue, see How to Design a Wall.
Thanks Martin
All good points to bring to the architect tomorrow.
Are there any articles on how best to air seal innie windows in thicker walls?
I’ll post how we get on
Thanks All
Kiefk,
Q. "Are there any articles on how best to air seal innie windows in thicker walls?"
A. Start with this article: Windows in Double-Stud Walls.
The short version: Most builders use canned spray foam to seal air leaks between a window and the window rough opening. This isn't a perfect solution, however, especially if you aim for a very low rate of air leakage. To reduce air leakage to a minimum, use a high quality tape on the interior side of the window to seal the crack between the window frame and the window rough opening.