Measure the door. Each door should be about 1/4" shy of the actual width. That is to incorporate the thickness of the hinge and some clearence. I know that a 24" bifold door( 2-12" ) are only 11-3/4" each.
Posts: 1718 | Location: Applachain | Registered: Feb 27, 2006
As a general rule of thumb, rough openings are 2" greater than the door size. this gives you enough room for the thickness of the two side jambs (usually 3/4" or less each) plus about a half inch of adjustment room to get things plumb.
Originally posted by ron45: In this case the rough opening is the finish opening because the Bi Folds have no jams.
Except that you cover the framing with either drywall or 1x stock. So your rough opening is 2" greater, as Jaybee mentions. If you wrap it with drywall it could be a little less than 2" since you'd have a little more than 1" of material (2 pieces of 1/2" drywall plus drywall compound) versus 1 1/2 (2 pieces of 1x at 3/4" thick).
Any advice given here is general in nature and is not necessarily valid for your given area. If in doubt check with your local codes enforcement department for what is required when doing electrical, plumbing or structural work on your house. Permits may or may not be required in your area and home owners may not be able to DIY some tasks. I have no way of knowing if you have the skills needed to complete the tasks you are asking about, when in doubt seek professional assistance.
My advice may be worth exactly what you pay me for it. :-) For the record I did not stay in a Holiday Inn Express last night.