Shed shelving advice...
 

I am planning on putting these style shelves in my 8x12' shed. Was curious on what type of fasteners to use where the diagonal bracing meets the stud (I circled the area in red).

Can I use 4 deck screws or do I have to go with carriage bolts?

Biggest span will be about 6 feet long, 12-16" deep. Only planning on putting bottles of pesticide, stuff like that on the shelving, nothing too heavy.

I'd rather do it right this time and second guess myself after my kids decide to climb up there and sit on the shelves....

Thanks for any advice....

Usually they can go on the side of the stud, screw them on.
If they land on the stud, just toe screw them

But get screws designed for structure. Don't use sheetrock or deck screws. Those are not designed to resist shear loads which this would be.

Could I find these types of screws at the big box stores?

I've always used deck screws

16d nails will work better than screws for the shear load, and if that doesn't let you sleep at night then go with the carriage bolts. Won't hurt anything, just take longer to install and cost more. I generally use 3" screws but I see your concern with kids hanging so I'd go the nail route.

Even better is to use one screw to pull the two overlapping pieces of lumber together and then use 16d common nails to nail it off..

So u guys think 16d nails will be enough to carry the load? I thought carriage bolts woukd be overkill but I figured let mw check here before I started....

If you have little ones to worry about, be careful if you use 16d nails to nail to the side of a stud. They are 3-1/2 inches long, so the ends will stick out unless you angle the nails.

What tools do you have? Do you have a drill that will fit between the studs to drill holes for carriage bolts? Air nailer? I think nails, screws or bolts will give good results. Use the fastener that makes it easiest. You could even use deck screws and glue.

I have a right angle impact driver that would work. I also have a compressor to run a palm nailer.

Could I use 3" nails so I don't have to worry about the ends sticking out past the wood?

I just did a similar job, 2 2x4s attached with deck screws. The screws I used were 3", but were only threaded for 1 1/2", got them at HD, they are yellow. If you drive them in and countersink a bit, the unthreaded shank will be at the shear location between the boards. Should hold better than fully threaded screws which will shear in that application.