Replies

1. GBA Editor
   Martin Holladay | Apr 20, 2019 05:12pm | #1

   Ian,
   The blue foam is probably XPS -- and green builders try to avoid using XPS for environmental reasons. Either EPS or polyiso is better. More information here: "Choosing Rigid Foam."

   You are planning to install R-10 of continuous rigid foam on the exterior of your 2x6 wall. In Vermont, that's not enough R-value to avoid moisture problems. More information here: "Calculating the Minimum Thickness of Rigid Foam Sheathing."

2. 
   ianatmb9 | Apr 21, 2019 08:00pm | #2

   Thanks, Martin. Appreciate the quick reply and links.

3. Expert Member
   Akos | Apr 21, 2019 09:17pm | #3

   Ian,

   Getting some insulation on the floor would also make a big difference in comfort in the winter. If you are heating the space all the time, best is bellow the concrete pad or if you are heating it only when needed, than above the concrete pad. Even 1" would make a big difference.

   I would also suggest some high windows, say foot tall along the wall a bit bellow the soffits. South facing would make a big difference in winter energy use but could create glare issues, north facing would bring in great diffuse light all year around but would cost a bit of extra heating. High windows also keep the walls free for equipment/storage.

   Unless you are occupying the shop full time or humidifying it in the winter, I wouldn't worry too much about condensation in the walls. The guidelines Martin suggest are for houses, in a workshop without a humidity source, the inside air quickly becomes as dry as outside air eliminating the condensation issues.

   Also be careful if you put in a roll up garage door. Those can be quite leaky and a big energy loss.

   I've had much better luck with building bi-folds out of insulated exterior door slabs and using standard exterior door weatherstripping/sealing/doorjambs. Bonus is you can use it as a normal entrance door and also get double pane glass inserts in them for cheap for a bit of additional light.

1. 
   ianatmb9 | May 16, 2019 12:01pm | #5

   Thanks, Akos.

   We have 2" of insulation under the slab, so should be all set there.

   The high windows are an interesting suggestion and something I might look into.

4. 
   NEplumber | Apr 23, 2019 05:02pm | #4

   Hi Ian,

   A heat pump would work in a shop. Some considerations;
   Dusty, dirty, solvents, wont go well with a heatpump indoor unit.
   Second, if your going to be opening a large door for any extended period of time in the peak winter (more then carrying in a few supplies) your pickup factor has to be accounted for. Radiant heat holds its heat in mass (ie concrete shop floor). Heated air will flow right out a door when opened.

   Consider a WWSD (warm weather shut down) on the appliance for heating season using a relay to turn off the unit above 55-60f.

1. 
   ianatmb9 | May 16, 2019 12:05pm | #6

   Good to know about the heat pump, Moe.

   We plan on having an explosion proof extractor fan at the opposition end of the space for spraying so I'm hoping that won't affect the heat pump. We'll also be paying very close attention to dust capture and removal.

5. 
   ianatmb9 | May 16, 2019 12:07pm | #7

   Here's a fairly simple SketchUp model I'm working on. It's my first time using the software.