Replies

1. 
   walta100 | May 27, 2025 11:16am | #1

   https://www.greenbuildingadvisor.com/article/how-to-design-a-wall

   I do not understand the question.

   You could leave the walls as they are with zero exterior insulation, that would be the min.

   Adding thick exterior insulation is risky in that when you removed the original siding and window trim all the flashing went with it. Properly installing new flashing around the old windows and doors and over the new insulation is difficult at best. The chances of a leak are high.

   Unless you double the existing R value the amount of energy saved well be so small that it will not be detectable.

   Generally, if you are having vinyl siding applied over the existing siding the thin layer of foam used as underlayment is ignored and not consider insulation. Note if you do this your primary water barrier will be caulking around your opening and will require annual checks and repairs.

   Walta

1. 
   fixd | May 27, 2025 12:28pm | #3

   Walta100
   What I'm asking is:
   Is their a bare min so that the the dew point and drying aren't effected, knowing I only have R10 in the stud cavity.

   Are you saying unless I have R20 in the stud cavity that I won't detect any energy saved.
   I'm confused, what would be the point of all the hype about putting a jacket on your house. (Unless it's new construction)
   Windows are bucked out, I am not worried about flashing. Confident I have that under control.
   Not confident of how little or how much exterior r value I need as to not create a problem.

2. 
   Malcolm_Taylor | May 27, 2025 11:54am | #2

   fixd,

   See Akos post #13 in your previous thread.
   https://www.greenbuildingadvisor.com/question/getting-close-to-pulling-the-trigger-but-need-some-help-confirmation

1. 
   fixd | May 27, 2025 12:45pm | #4

   Duh
   I missed that
   (You ever read so much when learning something new and get messed up,... That's me)
   In your opinion, is it worth it (ISO 2.5" or XPS 2") if the cost to purchase was around 3k. (2000 sq/f)

1. 
   Malcolm_Taylor | May 27, 2025 05:44pm | #5

   fixd,

   Yes I think so.