We are planning to convert our garage, which is inside the house, into a bedroom. The outer wall is currently 155 mm and the idea is to add additional insulation on the inside. Currently, the vapor barrier is directly under the drywall. After some inquiries, it seems the best option is to remove the drywall, frame up 45x45 against the existing studs, insulate, move the vapor barrier outside of that layer, then frame an additional round of 45x45 with insulation before drywalling. Does this sound reasonable? Does it matter which of the layers is vertical vs horizontal? We will not be running any electricity in that particular wall. Any other good tips for us to consider?
Construction veteran
· Norrland
· 340 posts
Hi! Sounds like a good plan. The easiest and most stable way is to first lay the studs horizontally and then the second round vertically. Absolutely correct to place the vapor barrier between the two new layers of studs 
a tip is to use obs boards and then the plasterboard. You won't regret it the day you need to attach shelves or something else, and you'll avoid having to find studs or fuss with Molly plugs and other things.
a tip is to use obs boards and then the plasterboard. You won't regret it the day you need to attach shelves or something else, and you'll avoid having to find studs or fuss with Molly plugs and other things.
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