Rafter size for 16ft Span

[ustmd]

USTMD, here I am setting my homemade steel trusses for my "tractor port".

Dfkrug,

Those are great looking trusses...of course you are giving me the perfect excuse to learn to weld and to buy a welder

 

[magicheater]

Hiya,

Looking for information/feedback.

Finally, I am going to build the workshop.

I am looking at having a 16 ft span on on a simple shed roof with a 2/12 pitch. I am in Central texas, so there is no snow load.
Even near the equator they put more pitch in their roofs.
I am trying to decide on the size of the rafters and spacing and I am looking for feedback from people who have experience with their buildings.

Depending on the tables, I look at, I can do 2x8, 2x10 or 2x12. My preference would be to stay at 24 oc, but I am willing to drop to 16 oc to add strength and drop to 2x8s (general easy of handling). Generally, the more the pitch one has the less you need in height of the rafters.

Any feedback would be appreciated.
I like the metal truss idea, put them 4' on center, run purloins out of 2X4's flat which gives you more nailing/screwing surface for the steel roofing and gives you a great opportunity to put 1.5' foam in between for insulation.
Thanks

Here are my thoughts in blue

 

[SPYDERLK]

FWIW...

#1 dense yellow pine is (pound for pound) stronger than steel...

I see you named the wood but not the steel. Steel strengths range from 30,000 to 600,000 PSI. The strongest wood, kaneelhart is around 30,000psi and has a density of about 1. Steel is about 6. So yes, that strongest wood is certainly stronger pound for pound than the weakest steel. But it is not stonger by weight than 200,000psi steel. And for the very strongest steels its not even a contest. Best to say "Wood is stronger than iron by weight".
larry

 

[dfkrug]

Those are great looking trusses...of course you are giving me the perfect excuse to learn to weld and to buy a welder

I spot welded the first one, but it is easier to use self-drilling screws, so
I did the others that way. Unfortunately, my Makita impact screw gun
just failed.

I am done with 6 of 11 trusses. They are easy to build, if a bit tedious.

I suppose I could have MIG welded them, and at 16 guage (.054"), it
would have been easy enough.....