How can I insulated the outside walls of a workshop without doing harm?

Charley Nelson
Charley Nelson
Updated: Aug. 27, 2021

I have recently decided, due to the astronimical costs of hydro in Ontario, to further insulate my shop. My exisiting shop is 2x4 framed, with R14 roxul and 6 mil vapour under drywall. (No AC) The exterior is poor mans board and batten. (1/2" plywood with 1x2 battons at 16"oc.) This combination, with a 4000 watt fan heater, costs about an additional $150 to $200 in hydro per month if I heat it to 16 degress C for 6 to 8 hours a day and maintain 'frost free' at night.

If I remove the battons, add 2" of foil clad ISO and vinyl siding to add R13, should I be concerned about moisture? What else should I be considering, beside a more economical heat source?

Thanks you in advance for your help


Responses (3)

Charley Nelson
Charley Nelson 2 years ago
Mike Reynolds 2 years ago

We may be misunderstanding each other Charley. I was running with the assumption that you had a vapour barrier already. The solution of adding 5 + inches rather than only 2 inches shouldn't make a difference to building inspectors, but it helps protect the walls. If you go with Mineral wool though, it doesn't matter how much you add, moisture will go through anywhere from 1 inch and up, it's with foam that you are best to go a bit thicker. Does that make sense? As for what to look for with degradation, I would target a method that works well so that you have nothing to look for. Does that make sense?