How To Install A Vapor Barrier On A Wall | Do It Yourself

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How To Install A Vapor Barrier On Walls

Danny O. from Toledo, OH wrote:

Hi Itchy,

Can you tell me a little about installing a vapor retarder on exterior walls?

It depends on how you're insulating the walls. If you are using kraft faced insulation batts, the kraft paper serves as a vapor barrier and is simply stapled to the face of the studs.

If you're using unfaced fiberglass batt insulation, you will have to use polyethylene (plastic) sheeting as a vapor barrier. This comes in rolls and you can purchase it to accommodate the height of your exterior walls (8 feet, 9 feet, 10 feet, etc.)

Once the walls are insulated, roll out the plastic on the floor to the length of the wall. Cut the sheeting with a utility knife and unfold it. Start in a top corner and staple it to the framing studs. Work your way completely across the top of the wall, stapling every 6" to 8". Once the vapor barrier is attached to the top, start stapling it to the wall studs, working from the top down, and smooth it out as you go so you don't have any large wrinkles in the sheeting. If you come across window openings in the framing, staple completely around them. Finally, staple to the bottom floor plate every 6" to 8".

Once attached use the utility knife and trim any excess and also cut out the window openings that you have covered with the vapor barrier. If you accidentally created a tear in the vapor retarder, patch it with a strip of duct tape.

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