Recent Comments and Answered Questions on Green Building Advisor

  • Martin Holladay | Feb 18,2018 04:44 PM EST
    Jim, Here is a link to an article that discusses your question: Using Rigid Foam As a Water-Resistive Barrier.
  • Martin Holladay | Feb 18,2018 04:02 PM EST
    Mike, You might want to read my article, When a Flue is Too Big.
  • Jon R | Feb 18,2018 02:13 PM EST
    I agree - it is possible to build something that would produce a tailored mix of heat/cool, ventilation and humidity for each room and deliver it via a dedicated duct. It would provide more ...
  • Andy Kosick | Feb 18,2018 01:25 PM EST
    First, Bravo for answering a controversial question with a lesson in room by room load calculation. Second, while recognizing that the Minotair and CERV are designed to provide ventilation, ...
  • Michael Maines | Feb 18,2018 01:02 PM EST
    Alex, the heat loss through the rebar is certainly measureable; concrete is thermally very conductive, and steel even more so. A three-dimensional finite element model would be needed to calculate ...
  • Michael Maines | Feb 18,2018 12:02 PM EST
    T Carlson, from the AISC Manual of Steel Construction, a textbook from college a long time ago, for allowable uniform load tables for 36 ksi steel. (Of course also ok for 50 ksi steel.) I also ...
  • Alex Stanton | Feb 18,2018 11:27 AM EST
    Martin, name is Alex, fixed my profile after the first post. Been a subscriber since I started designing the house last year but just haven’t had to post because I was able to glean what I needed ...
  • Martin Holladay | Feb 18,2018 11:21 AM EST
    Reid, I'm siding with Jon on this one. The Minotair and CERV controls basically aim to achieve good ventilation performance -- the heat recovery function (via the air source heat pump) is a ...
  • Jon R | Feb 18,2018 10:36 AM EST
    The advantage of a HRV connected heat pump is avoiding additional ducts. But I doubt they are designed to be able to independently control the amount of fresh air and heat going to a specific ...
  • Will Schebaum | Feb 18,2018 08:19 AM EST
    I have a similar question about branch box location. My installer who worked with Mitsubishi to get the details fine tuned says that a branch box can be installed outdoors as long as its ...
  • Reid Baldwin | Feb 18,2018 08:17 AM EST
    I labelled this a half-baked idea because I hadn't yet convinced myself it is a good idea nor convinced myself it is a bad idea. I agree with you that when the bedrooms are close to the family ...
  • Martin Holladay | Feb 18,2018 07:37 AM EST
    User-6804212, First of all, can you tell us your name? I'm not sure I understand your question. But it sounds as if your detail is similar to the detail shown in the illustration below. Are ...
  • Martin Holladay | Feb 18,2018 07:28 AM EST
    Jamie, I'm not sure what you mean by "building a slab on grade within frost lines." Did you mean to write "frost walls" instead of "frost lines"? In Toronto, the frost line is probably ...
  • Martin Holladay | Feb 18,2018 07:15 AM EST
    Jamie, Here is an analysis of the energy savings associated with HRVs or ERVs: Are HRVs Cost-Effective? You might consider using Lunos fans for ventilation. For more ...
  • Martin Holladay | Feb 18,2018 07:06 AM EST
    Paul, You should be able to explain to a building inspector -- even a Canadian one -- that a below-grade wall is not the same as an above-grade wall. Even a Canadian building inspector might be ...
  • Norman Bunn | Feb 18,2018 05:43 AM EST
    If you are forced by the inspector to use a vapor barrier, see if a vapor barrier paint is acceptable. If not, an adaptive vapor barrier like Membrain or Intello would be my next choice.
  • Jon R | Feb 18,2018 12:02 AM EST
    You can put valves on the return lines and adjust them such that head loss in each parallel loop is the same. A homerun system has much more pipe surface area and therefor even more heat loss ...
  • T Carlson | Feb 17,2018 10:52 PM EST
    @kj, thanks, good info. electricity is pretty spendy for you too I see. @Jeremy, curious where you are at or what climate zone you in? The minisplits are getting pretty popular as ...
  • T Carlson | Feb 17,2018 10:33 PM EST
    Michael, where are you getting your steel beam load tables from? Mine says for a 20' span 40/15 you need a w8x18, w8x10 will go 16', 36 ksi steel. 8' tributary width. Alexallo, I'm assuming you ...
  • Walter Ahlgrim | Feb 17,2018 08:32 PM EST
    If I understand your plan please consider 1 You will need a check valve for each return. 2 The pump will be supplying parallel water circuits, so the flow rates of each circuit will be ...
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