Replies

1. 
   rlrefalo | Jun 07, 2009 03:03am | #1

   24 inch centers will be fine with that building.  If you're concerned with snow load, go with a gabled roof, 2x6 rafters should do it. On 24 inch centers go with 5/8 inch ply on the roof. 

   Rich

1. 
   luvnordic | Jun 07, 2009 03:13am | #2

   Cool, thank you

2. 
   Oak River Mike | Jun 07, 2009 03:19am | #3

   I would personally go with 16 inch as its going to give you a stronger structure and provide more internal areas for attaching shelving and such. And in a building this size you might use a dozen extra 2 x 4s.  At my local Lowes they are $1.98 so thats like $24.

   And it might be just me but I would rethink the 2 x 4 rafters.  Those might be a little scary to be up on when putting on the roof covering.  You might at least upgrade to a 2 x 6?

   But then again, I overbuild everything!  Maybe thats why I am not making much money in this business?!  :)

1. 
   luvnordic | Jun 07, 2009 03:34am | #4

   OK, you convinced me. I'll go with 16 inch centers and use 2x6s for the roof rafters. Better safe than sorry.  Thanks for the info

1. 
   ptp | Jun 07, 2009 03:53am | #5

   There's a construction principal that I feel I've heard somewhere before: "It's better to over-build than to build it over."

1. 
   Oak River Mike | Jun 07, 2009 04:09am | #6

   I like that one PTP!

2. 
   BilljustBill | Jun 07, 2009 07:50am | #7

   There's a construction principal that I feel I've heard somewhere before: "It's better to over-build than to build it over."

   I've always thought that unless it "Floats or Flys", overbuilding is a good thing.... ;>)

   Add to that perspective the use of Lowes' "Cull Cart" lumber at 10cents on the dollar, and you've got lots of lumber, lots of additonal strength and lots less of costs...

   Bill

3. 
   renosteinke | Jun 07, 2009 06:21pm | #8

   I see no problem with 24" spacings, but I would like to make some observations.

   The first is that I really don't think there's musc difference in strength between the two. I think that you're better served by making a frame / panel that is stiffer - and vertical studs are not, by themselves, very stiff. Let's look a bit at how various loads / forces will act on the structure.

   Let's start at the roof. We'll use a gable style for a starting point.

   Any force - weight, snow, whatever .... is going to push 'down.' This means that the edges will in turn push 'out,' as the ridge tries to drop down. That's why trusses - even simplt triangles - are so strong; the bottom cord (rafter) ties the outer edges together, preventing them from spreading. That spreading force is then re-directed downward. Since this is a "tensile," or stretching load on the rafters, you could make the bottom cord out of rope if you wanted to.

   Now for the walls.

   Since the walls are verticle, they're already inclined to work just fine in transferring the roof load - as long as they remain stiff and straight. Since they're stiffer in the corners (getting help from the next section), they'll tend to bow 'out' in the middle. Again, this issue is addressed by the roof rafters, which work to keep is all in line.

   Apart from the tendency to bow out, walls will also -in response to wind, for example - tend to skew, or twist to the side. This is a natural consequence of walls being a rather weak 'rectangle' shape. The secret here is to make that rectangle into a set of very stiff triangles.

   Adding studs, or using larger lumber, does nothing to keep the wall square. However, if the sheathing is solid (as in plywood, rather than drywall), this sheathing will allow the wall to become, essentially, a set of triangles. You just can't see the diagonal bracing, as it's inside the sheathing. In the 'old days' walls were often sheathed with planks set at an angle for this very reason.

   As you might guess, the key to everything staying together is the connections between pieces. That's where all those Simpson connectors come in; there's a lot of strength in that sheet metal, and your nails have forces pulling across them, rather than trying to pull them out.

   Finally, with every force - snow, wind, simple weight - now pushing 'down,' we need to have a solid base to tie it all together. In practice, this means either a concrete slab, or afloor frame set across pier blocks, above the ground.

   How would I do it? Given a choice, I'd have an oversize slab poured - taking pains to make it as square and flat as I could. I would then use this as a platform to pre-fab my wall sections. I'd make the walls from a 'sandwich' of T-111, 2x2's, and pegboard .... everything glued as well as nailed, and with metal brackets in the corners. (I must confess to using 2x4's, on edge, where panels meet). (The pegboard isn't for hanging pegs; the inside sheathing is part of the strength of this sandwich. Plywood is also OK).

   I'd use a couple long (say, 1/4 x 3) lag bolts to hold the panels to each other. I might even add some metal brackets inside the corners, just to keep it all square.

   I'd do the same for the roof. By pre-fabbing the trusses on the ground, I can make sure that they're all exactly the same size and shape. I can even add a little 'stop' to one end of the rafter, to assist me in setting them perfectly in line.

   Now, at this point it will help if you had made the end trusses as part of the end panels. You will be able to mount temporary supports for the trusses on one side, to hold them in place as you set the others.

   Once the trusses are up, you can begin to attach the sheathing, removing the temporary ties as you go along. Then, cover the sheathing with the roofing of choice.

   When I made my shed, I used pier blocks. Some folks questioned the 1-1/8" subfloor I put in. Well, maybe the final shed doesn't 'need' that solid a floor - but my ladder was rock-solid as I worked on the roof structure!

   The proof has been in the results. My shed, with it's 2-1/2" thick walls, has weathered well. My neighbor built a much nicer shed, using a corrupted version of stud framing - only to have it fall apart twice. (I tried to help - but got the brush-off).

1. 
   Oak River Mike | Jun 07, 2009 09:55pm | #9

   ren,

   I build for wind loads and adding studs does increase the strength of the walls.  Its not a gravity load I intend to increase with adding studs but the MFWR (Main Force Wind Resistance.  Having that extra stud in the width of a sheet of plywood on the walls reduces the span between the studs.  Sure, its only 8" (the difference between 16" o.c. and 24" o.c.) but it helps.

   Mike

1. 
   frammer52 | Jun 08, 2009 01:24am | #10

   Mike, it is only a shed.

1. 
   Oak River Mike | Jun 08, 2009 02:04am | #12

   Frammer,

   Yeah I know...like I said I just overbuild everything.

   I guess my years from working at the local building dept as a manager shine through as we had a guy sue another neighbor because their shed blew into their house and caused some damage and claims it was due to his lack of construction skills.  Believe it or not it took up nearly two months of my time! 

   So I guess if $24 of 2 x 4s prevents this, to me its worth it.

   Mike

1. 
   frammer52 | Jun 08, 2009 02:08am | #13

   claims it was due to his lack of construction skills>>>>>>>>>>>>>

   Pretty funny there!

2. 
   renosteinke | Jun 08, 2009 05:36am | #14

   I won't contradict you; larger studs, and more of them, do have an effect. I over-simplified, in part because of the size of his project, and because it's doesn't take much of a design 'goof' to cancel out any gain you might have.

   Someone has mentioned building a garage. Let's not under-estimate the structural problems in having that big opening in one side, or the heavy weight the door places on the trusses. At some point you need to either hire a pro, or slavishly copy a proven design.

2. 
   luvnordic | Jun 08, 2009 01:59am | #11

   Thank you for all the great information. I will be building a garage in the future and this will really help with that also.

   Thanks again,

   Jerry