Truss Spacing and load question?

[City Farmer]

Let's say I vent from the eave, how do you keep insects, bats & small birds from making a home in the attic? I would assume there's a moulded screen that follows the contour of the metal ribs or Is there a trick to attaching screen to the underside of the roof?

 

[tcreeley]

2nd guessing, it seems like you could measure your trusses, their placement. the wood used, the length, the pitch (rise/run) and find some truss tables. See what they say for non snow load, then snow load. You can look up the recommended snow loads for your area. See what it takes to build the trusses you have, and that will tell you roughly their capacity.
Or go to a Home depot and tell them you want trusses with your dimensions and ask them what roofing they would recommend.
Structural engineer is good- but you can get the same job done without him.
Enjoy.

ventilation - wire screen cut to oversize, press into place on top of good fresh silicon bead - that's what I would do for a shortcut. I am sure there is a product sold that does the job.

They do sell foam that matches the profile of the metal roofing that you install before you screw the roofing down to seal it.

I used this under my ridge vent on my metal roofing. Keeps the bugs and snow out. Lets air through.
GAF Cobra Exhaust Vent 1-1/2 in. x 2 ft. Mesh Roll Ridge Vent in Black-25 - The Home Depot

 

[LD1]

As.i said, sure you can measure truss spacing, design, lumber dimensions, etc. But that is only 1/3 of the puzzle. What species and what grade?

I know this example isn't a truss, but....
A 2x6 stud grade, 16" spacing, and 50# total load is only rated to span 7'8"
Same parameters but up the grade to #1 and you can now span 9'4"

Up it to a 2400f-2.0e msr board and you can now span 10'6". (Which btw is more than some grades of 2x8)

So you cannot simply go by the dimensions of the lumber. Grade is equally important.

And as a truss, the plates are key in the calculations as well.
Do you have 6x16 plates? Or 8x22? And how thick?

You can have a 2 trusses that on the surface look the same. But one may be common #2 grade lumber and smaller plates (but plenty strong for the lumber grade) and that truss may be only a 20# or less snow load.

Same dimension lumber, same truss spacing, but increase to msr boards and heavier plates may get you a 40# rated truss.

 

[City Farmer]

As.i said, sure you can measure truss spacing, design, lumber dimensions, etc. But that is only 1/3 of the puzzle. What species and what grade?

I know this example isn't a truss, but....
A 2x6 stud grade, 16" spacing, and 50# total load is only rated to span 7'8"
Same parameters but up the grade to #1 and you can now span 9'4"

Up it to a 2400f-2.0e msr board and you can now span 10'6". (Which btw is more than some grades of 2x8)

So you cannot simply go by the dimensions of the lumber. Grade is equally important.

And as a truss, the plates are key in the calculations as well.
Do you have 6x16 plates? Or 8x22? And how thick?

You can have a 2 trusses that on the surface look the same. But one may be common #2 grade lumber and smaller plates (but plenty strong for the lumber grade) and that truss may be only a 20# or less snow load.

Same dimension lumber, same truss spacing, but increase to msr boards and heavier plates may get you a 40# rated truss.

Yep, all you guys were right. I called a truss company yesterday and it's not possible to sheet and shingle this building so it's getting a new metal roof. I'd have to add more poles/trusses & increase the size of the truss carriers for shingled roof.

Next week is cement, I finished the rebar yesterday. I need 19 yards for the 6" floor. 1/2" re-bar in a 12"-14" tied grid with angle iron around the perimeter to screed from.

No measuring, I just threw the rebar down and got to work. I bought the rebar from a guy in Detroit for $500. A lot of the pieces were bent but I saved about $75 instead of buying it from Menards.

Here's a picture at the 6hr mark. I broke the rebar installation in to 3rd's. 2hrs of squatting is about all my back & knees can handle at a time. I'm keeping track of the hrs and the cost of fixing this barn up.

Rebar, angle iron, plastic stand-offs, wire ties & twist tool- $650
Cement - $2340
I'm at $3k for the 25'x40' so far.

Thanks again for all the help everyone. :thumbsup:

 

[1stDeuce]

Wow, nice work!! Are you planning to put in a 100 ton stamp press or something?? 6" with rebar should hold up to industrial abuse!! I'm planning to go 4" glass fiber reinforced, and don't expect it'll ever crack...

 

[City Farmer]

Wow, nice work!! Are you planning to put in a 100 ton stamp press or something?? 6" with rebar should hold up to industrial abuse!! I'm planning to go 4" glass fiber reinforced, and don't expect it'll ever crack...

No 100ton press or anything like that but I've been collecting some machines for a little work shop. I have enough projects I wanna build to keep me busy for a lifetime. Why wouldn't you add the some steel, rebar is cheap? You never know what the future is going to bring. . :thumbsup:
I pour the floor Thursday.