Which would be stronger for my 18x28 shop roof?

[canada340]

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[jproffer]

You probably should keep these threads together, but:

Before building trusses, check with your local building dept. Around here to build trusses, you have to be certified to do so.

As I said in the other thread, if you stick build, you will need 2x8 rafters minimum. Trusses use 2x4's I know, but they are engineered for strength and stability. A 2x4 rafter, by it's self, is asking for trouble, I would be surprised if you would be able to get on it to roof it, not to mention the weight of the shingles.

As for the sagging question, short answer is yes, unless you post it in the center. You could step up to 2x12's and maybe use 3 layers to span 28 feet.

[montytx]

You also would have a space problem with your ridge board if you use 2 2x8s. You will have to rip a compound angle runner board to support the roofing wood.

[Joe Carola]

Mike,

This shop is as baisic as baisic gets to build. You have an 18' x 28' shop to build.

Forget the 2x4's for rafters. If code permits you (If your even gettings permits) all you need is with a 4/12 pitch is 2x6 rafters with a single 2x8 ridge and 2x4 collar ties. Get two 14' 2x8's for the ridge and butt them into eachother. That's all you need. Get 18' 2x8 ceiling joists with double rows of strongback on top(2x4 on a flat and 2x6 on edge) or 2x10 or 2x12 ceiling joists for storage and your done.

Joe Carola

[canada340]

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[Sweep]

Well, I got suckered by the other post which apparently you still have neglected to edited, and it has momentarily irritated me enough to give you some honest professional advice without maintaining the usual courteous tone of this forum.

Your diagrams, descriptions and responses indicate that you have little familiarity with, and no understanding of structural design and common building practices. It is obvious to me that you are in way over your head. Therefore, I must warn you that relying on information from this forum or any other internet site, however good it might be, is foolish and could easily lead to property loss or personal injury.

[Rich]

haha Sweep.. in the future just head them over to read this http://www.construction-resource.com/tos.php

[Sweep]

Thanks Rich. Sorry for the outburst. I think I have a greater tolerance for amateur designers than most professionals but the naive presumption of that elaborate truss drawing must have found a raw nerve somewhere. In the future, I will avoid all threads that begin with "I'm building a shed/garage/workshop."

[canada340]

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[VALENT]

I think Joe has given you about all the advice you need.(and very good advice, in my opinion) The 2x6s will be plenty ample. The 18'2x8s are to serve as your ridge board. Then get additional 2x8s to serve as your ceiling joists and add the strongbacks. I do think you will need the ceiling joists regardless of storage above or not but may be able to increase the oc spacing if no storage is needed.

[VALENT]

Oh by the way, only now have I seen the other post and Sweep(and others) definitely gave you some good advice there.

[Sweep]

If you want more I will accomodate you.

It is not the advice that you seek that I find objectionable; it is that instead of just asking for it like many others new to this forum, you offer two complicated and structurally specious designs and ask for members here to choose which one is stronger. I offer no apology for finding this presumptuous and tiresome.
Failing to edit your original post just gave me a reason to tell you the unvarnished truth, which I suspect is painful: Get a builder and pay him to design your project, you have no idea what you are doing.

Or you could try the very professional Journal of Light Construction forum.
http://forums.jlconline.com/forums/index.php

A building of this nature is thoroughly detailed in any building code, which is where anyone, even a professional, should start. Do your homework first and please, do not, under any circumstances, try to design a truss.

I knew a guy in high school who would frequently ask me pointless speculative questions like "if a bear and a tiger fought to the death which one would win?" I hated him. Your name wouldn't be Clark by any chance?

[VALENT]

Everyone knows the tiger would win.

[Joe Bartok]

"if a bear and a tiger fought to the death which one would win?"
If they're fighting to the death, neither one wins.
canada, you might want to search the JLC Forum and check out their policy re DIYers before you decide to post.

[giddonah]

sweep, you're awesome.

Canada, I hope you just take this as a little newbie roughing and post furthur questions as you have them.

[VALENT]

joe, the fight is over once one of them dies. The other is the victor.

[Joe Bartok]

Ooops! I thought the bear and tiger both died. :lol:
Sorry to see the "roughing", but I think everyone meant well and was trying to do the right thing. "Internet engineering" is a bad idea. I also just realized that the images in the link (http://constructionforumsonline.com/viewtopic.php?t=520&start=15) inserted in the Roofing, Rafter and Ridge Beam Help Needed (http://www.construction-resource.com/forum/ftopic4210.html) thread aren't visible; I've attached them this post.
If your heart's set on a clear span, there's one way of achieving it. But: Those are 14" - 15" diameter logs about 20' long. The ridge beams and purlins are fully housed and supported (there's another truss off to the right in the image). The lags holding those connectors at the joints are 1/2" × 8", there are through bolts connecting other roof members (1" in the trusses, as I recall).
If we want to frame something like this, we're relying only on the nails to hold everything together. The material in the ridge beam and purlins will be smaller, 2 ×?. We need more purlins, what spacing O.C. is required? What are the local snow/seismic/wind loads? If you read on to page #2 in that link, I brought up these very concerns, hoping to forestall a dialogue heading in just the direction this one has taken.
I don't think you'll find anyone who considers their conduct professional willing to touch issues like this via the Internet.

[montytx]

Its obviously the bear. They like to fight mano y mano. Tigers are group predators. It would be in way over its head.

[canada340]

If you want more I will accomodate you.

It is not the advice that you seek that I find objectionable; it is that instead of just asking for it like many others new to this forum, you offer two complicated and structurally specious designs and ask for members here to choose which one is stronger. I offer no apology for finding this presumptuous and tiresome.
Failing to edit your original post just gave me a reason to tell you the unvarnished truth, which I suspect is painful: Get a builder and pay him to design your project, you have no idea what you are doing.

Or you could try the very professional Journal of Light Construction forum.
http://forums.jlconline.com/forums/index.php

A building of this nature is thoroughly detailed in any building code, which is where anyone, even a professional, should start. Do your homework first and please, do not, under any circumstances, try to design a truss.

I knew a guy in high school who would frequently ask me pointless speculative questions like "if a bear and a tiger fought to the death which one would win?" I hated him. Your name wouldn't be Clark by any chance?

Hey Sweep,

I found that "Edit my post button" you been bitchen about!

Ordered my 1x2 rafters and 2x2-ridge beam lumber for my roof today! Can’t wait to start stick building …weeeeee!

Now if I could just find the “Delete my Account Button”…. Maybe it’s under “If your new to doing something and your not a professional Don’t Fucking Post On This Forum”..Lol, maybe the mod will oblige my delete account request for me….

See Ya.

[tooltroll]

Everyone knows the tiger would win.
Yeah, but Mr. Spock can kick Han Solo's @$$ anyday... :lol:

[Joe Bartok]

Spock cheats ... he's got an unfair advantage with that "Vulcan nerve pinch".

[tooltroll]

Spock cheats ... he's got an unfair advantage with that "Vulcan nerve pinch".

Aww, that's Han's own fault. He's the one who said "Hokey religions and mysticism are no match for a blaster at your side!" :wink: