beginning sub floors and wall and roof sheathing

[BigMish]

Sub floors and wall and roof sheathing should all be begun 3/4" from the edge so that the seems between ply wood sheets fall in the middle of joists, studs and rafters that are spaced evenly at 12", 16" or 24", right?

Seems to me if the plywood was begun at the edge then the far edge of the plywood sheet would fall on the near edge of the joist, stud or rafter. However, none of the books I have seem to mention this and all of the photos contained seem to have the plywood flush with what ever it's sitting on.

[JRR]

I think I've seen it covered in some books, but can't remember which.  Usually you have to cut off a strip, 3/4" or so, on the beginning piece.

It's one of those oversights you only do once.

[BigMish]

Wouldn't you need to add a 3/4 " strip and not remove it? In the image below I've placed the piece of ply ¾" to the right of the outer edge of the rim joist, allowing the joint between that piece and the next to fall in the middle of the 10th joist (this of course ignores the fact that you'd really want 1/6" space between the two plywood sheets for expansion). If I where to remove ¾" from this piece it would fall ¾" short of the joist. If I understand what you're saying, I could add a ¾ strip to the left of the plywood sheet so the ply would be flush with the rim joist.

[PA-Builder]

Start your first rafter/joist so that the center of that rafter/joist is 16" from the outermost edge of the building, where you plan on starting your sheets.  Then put the centers of remaining rafters/joists at 16".  

[hobbiest]

All the framing should be done this way, joists, studs, rafters.  Easiest way to do it is to measure 15 1/4" from the end of the wall, put a line, stud goes after this line.  Then put a nail in the line, and pull 16, X, 32, X, etc.  Don't forget that where one wall butts into another, you must measure from outside of building, or you will end up off layout.  Hope I didn't just confuse anybody more.  Don't forget to stagger the seams on your subfloor either.  Best to have at least two joists between edges, never meet 4 corners (unless it just can't be helped, like when you just can't bring yourself to cut another sheet at the end of the floor or something).

[peg_688]

I do it sort of like Hobbist , except I mark at 16 3/4, and make my X back , so I call it 16 3/4 and back off, works the same for 24"centers, 24 3/4" and back off. This way I can just hook my tape and lay out. On long walls I do use a long tape hooked or held with a nail from my first layout.

Another thing I do is cut my plates to lenght making sure my layout falls 1/2 way on a joint so a syud falls on 1/2 way on the joints in the bottom and sub top plate.

After I cut my plates accordingly , I go back and layout my door and window holes/ openings , and all interior partion backers , Then once those are layed out I go back and do the stud layout . So it's a three step process, proper lenght plates , door /window & partion layout , then stud layout.

I do this because your stud layout if done first will conflict with the openings and partion layout and you'll get so many crossed out marks it becomes hard to figure out what goes where with all the conflisting lines .

 Rafter and/or truss layout is about the same , unless you have eave overhangs to consider, so it becomes a depends deal then.

This may be TMI , (To Much Info) so I'll stop here. So you can think about that, and digest whats above.  

[JRR]

My comment has to do with flooring or sheating (like T1-11) that have interlocking/overlap edges ... and where the sheets are a little more than 4' wide.

[peg_688]

The over lap on T1-11 brings you back to a 16" OC layout, no need to adjust / add  if layed out normally.  

[hobbiest]

T&G sheeting, just start even with the first edge.  Measure a sheet from tongue to opposite edge.  if 49", measure in 49" from each corner, and make a mark, snap a chalk line between.  This is the important course to get straight.  After that, seat all sheets the same, and you should be good to go.  Don't forget that different manufactures require different expansion gaps.  usually 1/8".  We usually just drive the sheets home.  Use a piece of scrap 2x4 on the groove edge and smack it with the sledge hammer.  It helps to have someone stand on the seam that is going together to thread the tongue and groove.  

[BigMish]

Think i got it. I went back and reviewed Nash's DIYSHB and he's saying the same, just missed it.

Thanks guys, M