Recent Comments and Answered Questions on Green Building Advisor

  • Dana Dorsett | May 21,2018 11:24 AM EDT
    The irrelevance of the R-ratio for dew point control notwithstanding the ratio is still important relative to meeting IRC code minimums, which allows a reduced total-R if/when the exterior R is at ...
  • Malcolm Taylor | May 21,2018 11:15 AM EDT
    Stewart commented that "Hands-on involvement by owner is the main way to keep down costs." Given that labour is a significant part of all construction budgets, this is true of new construction ...
  • Martin Holladay | May 21,2018 10:27 AM EDT
    Stewart, The chainsaw retrofit in Saskatoon was groundbreaking because it was the first time that an entirely new thermal envelope was installed on the exterior side of an existing house. The ...
  • Stewart Herman | May 21,2018 10:14 AM EDT
    With 'almost ten years ago" I was referring to your (2009) post, not the project itself. Sorry for the unclear reference. The Saskatoon project was a pretty radical 'weatherization' project, ...
  • J M | May 21,2018 10:09 AM EDT
    Australia is systematically eradicating them, they're one of the worst invasive species on the planet. Wind has nothing on major sources of mortality and is a problem that has been largely ...
  • Martin Holladay | May 21,2018 10:05 AM EDT
    Stewart, You wrote, "While the original project you seem to admire (Saskatoon--almost ten years ago!)..." In fact, the original chainsaw retrofit in Saskatoon occurred in 1982, which (if my ...
  • Stewart Herman | May 21,2018 09:39 AM EDT
    Thanks, Martin, for forwarding such a compendious list of articles. What is to be learned, in aggregate? 1. Of the 20+ retrofits here, most do not involve seeking certification as net zero. ...
  • Dana Dorsett | May 21,2018 09:31 AM EDT
    Nissan is rolling out package deals of Nissan Leaf + PV + EV + home battery + smart charging in the UK! Just to make it more fun, for the home battery portion there is the option of "second ...
  • Martin Holladay | May 21,2018 09:14 AM EDT
    Jameson, You don't have to worry about the ratio of interior to exterior rigid foam, because CMU walls aren't subject to rot. If you research ICF walls, you'll realize that some brands of ICF ...
  • Peter Engle | May 21,2018 09:04 AM EDT
    Please also describe your crawlspace. Is it vented to the outside? Is there insulation in the floors or on the walls? Is there a ground cover? Your air conditioner cycling does not seem ...
  • Jameson Taylor | May 21,2018 08:57 AM EDT
    Thanks for the answers. Dana - That link is helpful, I'll definitely spend some time looking into codes for R-values. So it seems that depending on how much insulation is on ...
  • Martin Holladay | May 21,2018 06:51 AM EDT
    Andy, Looking into the topic more deeply, I realize that demand-control ventilation (using CO2 sensors) is fairly common for commercial systems. There isn't any reason (other than cost) that ...
  • Martin Holladay | May 21,2018 05:25 AM EDT
    Max, Either approach will work. Before you commit to the spray foam option, consult a spray foam contractor to make sure that access is adequate. A 2-foot-high crawlspace is rather tight -- you ...
  • Martin Holladay | May 21,2018 05:19 AM EDT
    Stanger, First of all, can you tell us your name? You haven't really described a problem other than high electricity bills. Before we can help, we need to know the answers to the following ...
  • Martin Holladay | May 21,2018 05:15 AM EDT
    Ross, Malcolm seems to understand your question, but I'm not sure I do. The most important question is: Are you planning to install mineral wool batts directly against concrete? If you are, ...
  • Chris B. | May 20,2018 06:11 PM EDT
    Thanks for the input. I can't find anyone around here who still does open cell anyway - they all want to do closed. When I asked AMVIC about it, they responded that I could install any cavity ...
  • Malcolm Taylor | May 20,2018 05:33 PM EDT
    Ross, Yes they will compress fine. You just have to watch you don't tear them pushing them through.
  • Jan Juran | May 20,2018 04:14 PM EDT
    Hi L.T.: according to htts//pvwatts.nrel.gov 500 watts of PV panels in a grid tied system near Tampa FL should generate 782 KwHrs per year, more than enough electricity to run both an efficient ...
  • Calum Wilde | May 20,2018 07:35 AM EDT
    Before you can spec anything else you need to define your wall assemblies and roof assembly so you can predict your insulation and airtightness levels. Will there be insulation under the new ...
  • Martin Holladay | May 20,2018 06:15 AM EDT
    C.D., Every house needs a well-defined thermal boundary. In most homes, the attic is outside of this thermal boundary. If that's the case at your house, you have what is called a vented ...
Register for a free account and join the conversation


Get a free account and join the conversation!
Become a GBA PRO!