Replies

1. 
   user-723121 | May 02, 2024 02:59pm | #1

   I would be inclined to try and work with the younger builder, this will be a good learning opportunity. May set this builder on a path that may otherwise not have been taken. Have a good plan starting out and with close supervision all shall be well. We all need to start somewhere on the path to more efficient building. Do not try to convince an established builder to change their ways and build to your specifications, this is a waste of your time. As I read in the NYT comments recently, "you can't make someone to understand that does not want to understand".

   Doug

2. 
   otinkyad | May 02, 2024 04:43pm | #2

   Doug, thanks very much for that perspective. Right, that's very much along the lines I was thinking/hoping, so definitely I'm hopeful about working with him.

   It could still be useful though if I could point him to specific peers in the area who use these techniques -- both to persuade him that they are not wacky, and so he could maybe get hands-on tips (how *exactly* do you do furring over exterior insulation...? What screws..? How do you flash windows with exterior insulation and rainscreen..?) I've printed out and given him articles about all of that, but it's not the same for him as hearing from a builder who does it. So hopefully someone on GBA has some experiences with builders in Iowa who could be mentors or at least reference points or something like that..

   Thanks again, good to know that the younger builder approach may be a good one --

1. 
   user-723121 | May 03, 2024 09:43am | #4

   Otin,

   Where are you in Iowa and what are the performance metrics you are aiming for? I worked with a self builder (provided electrical boxes) years ago and they built a double wall in IA. This would be something to consider, easy to build and high performance. Exterior insulation is a waste of time and money in my opinion and is troublesome to weatherize. Not for the newbie builder. Just build thicker and tighter, you will get results and build quite conventionally with standard materials and techniques.

   Doug

1. 
   otinkyad | May 03, 2024 01:32pm | #6

   Thanks again, Doug.

   Have not thought in detail yet about precise metrics. All my thinking is driven by trying to keep things dry (mold-phobia, as mentioned in my original post) and/or allowing to dry. So I've focused on keeping outer sheathing warm (hence hopefully dry) via exterior insulation, and on airtightness to reduce moisture-laden air infiltrating/exfiltrating into the inner cavity. That's led me to think ~R 7.5 exterior insulation (mineral wool) and ACH50 of maybe 2 if possible. No metrics in mind beyond that so far.

   I think I read on GBA somewhere some discussion (maybe from Ben Bogie? Michael Maines..? not finding it now, and I don't mean to misattribute) about double stud walls being difficult to get right for a builder without experience in them, and so I had not investigated them much -- interesting that you have the opposite view. Will look at those again.

   I'm in Iowa City, so any references you have would be helpful!

3. 
   BirchwoodBill | May 03, 2024 06:28am | #3

   Are you looking for a lump sum bid or a time and materials bid? There is a learning curve with methods that need to be factored into the cost model, I.e. more labor hours.

4. 
   otinkyad | May 03, 2024 11:20am | #5

   BirchwoodBill,

   Had been thinking lump-sum bid. Having to factor in the learning curve was not something I'd thought about, but makes a lot of sense now you've mentioned it -- thanks!