Posted By bp f150 on 23 Jan 2011 11:59 PM
[...]
Also I have read that there is a diminishing return to higher R-value in airtight homes however I have never really read a scientific reports on this.
[...]

Posted By vkykam on 24 Jan 2011 10:06 PM
bp f150,

, Chris,

$0.80/sqft is probably correct, the OP is probably referring to the 1.75" and not the board foot EPS pricing.

Victor
www.ecobuilthome.ca
A 4350sqft Net Zero Energy initiative

Thank you for the replies.

Victor : Thank you for your expertice in house contruction in Ontario. I consulted the website for the house you mentionned and it seems very good that you where able to make it netzero house. The SIP company that I was looking into does not have Ontario stamps, however they will in the near future since they will be setting up shop in northern Ontario. 

What splining practice was used to join the panels on your project ? What thickness panel did you end up using ? And do you have any regrets on your choice?

I to am jealous of the pricing our friends to the south have.

I am open to feedback from others on my original questions.

Thanks again.

Victor,

Thank you for the response. The company in question is Metaform Building Systems. Do you have any knowledge of them? I was considering the above and bellow grade application.  They to use a 2x spline (PWF - below grade / SPF - above grade) just like you mentionned. In our area, the building inspector looks to roof and floor systems for engineering and makes sure points loads are distibuted to the walls, floor cripples, to foundation walls and then footing. When talking with him, he said from the technical data that he did not object to using the SIP panels for the intend use. However I want to make a good decision for my family and checking account and not just have the cities approval.

Izerarc,

Thanks for a comparison to your project, it is intersting to see that the ROI is 50 years (if the price of fuel/electric stays the same as the salemans always add when trying to sell you the upgraded panel). I would like to calculate heat/cool loads, unfortunatly I do not have much experience with this and from what I understand there are programs that use algorythmes to calculate it.  Do you have any suggestions that could lead me in the right direction ? I believe that my ROI would much less since our climate is very cold (long and cold winters)

The following values are average daily temps in degrees Celcius.

   Nov         Dec         Jan         Feb         Mar
   -4         -13.2       -17.5      -14.4       -7.7

Thank you!

I've looked at Titanwall briefly, there's some talk of it around here, but in the city here, building departments are fairly strict on the stamps, so I didn't look any further.  It certainly looks interesting that it's not a wood sheathing.  Have you had a quote from them?  If so, do you mind sharing the costs?  I'd like to compare them against a "traditional" SIP panel in terms of price.

For the windows, there's the U/R value, and there's air infiltration, which can be a big difference.  Our house is 20+ fibertec windows, and the casements are performing phenominally (triple pane, U 0.13 fixed, U 0.18 operable), but the 3 sliders we have in the basement, there's a draft coming in when we're hitting colder temperatures like today.  So, as a start, I'd look at positive pressure close windows such as casements, and then look at whether there's any value in upgrading to better performing windows.  The window selection can come at a slightly later stage, perhaps after an initial heat loss calc done for whatever your minimum choice of windows, and then from there work your way up to see if there's any benefit by upping the insulative value.

Victor
www.ecobuilthome.ca
A 4350sqft cold climate Net Zero Initiative