G'day and welcome back to Buildsum and in this video. I want to go through the calculations To work out how wide we're going to make our opening When we build our frame our opening for a door So obviously in that opening We've got to fit our door, our jamb, a little bit of room for packing So we have to make it a little bit wider than the actual door is normally on the plan They'll just tell us. What size door is going to go in the opening. We have to work out the widths for ourselves, so We have a look down on top of the wall and get rid of the frame So we're gonna get left with our Door, jamb and a little bit of packing on both sides It's obviously the first thing and the largest thing we have to consider is the width of the door so 820 is a fairly standard size and You know standard sizes includes 770, 720, 670 and down to 620 but nowadays you can just about get any door width you want So the first thing is obviously the width of the door this case it's 820 then on each end We've got to consider the Thickness of the jamb material the thickness of the narrower piece of jamb material not with a wider piece up here Just how wide that is so 15mm in this case could be 18mm, 19mm. So whatever the thickness of your jamb material is going to be that has to be factored in You also have to factor in the clearance you're gonna have between Your door and the famb material so 3mm fairly typical if you're going to paint the door and the jamb If you're going to stain it or put a clear finish on it. You might be able to get away with 2mm Right, so we've got a allowance for our clearance there, and then we have to have some packing just in case our Studs are slightly out of whack they're not quite plumb a little bit of wiggle room, so I've allowed 10mm packing between the jamb and the start on this side and of course those dimensions have to get repeated on the Other side so we allow them all twice So if we add all those up That gives us our Opening between our studs now. You know obviously 4mm to get us up to 880 We could quite easily just say we're gonna put them in that 880 It just mean to be a little bit more packing on either side so That'll give us we go back to our frame that gives us an 876mm or 0.876m Opening and as I said I'd probably just go to 880 opening between our two studs in our wall G'day again, I'm back Just let you know if you like this video you can subscribe to my youtube channel or follow me on Facebook So you don't miss out on more great videos