Trussed garage -storage on trusses

[JUNEBUG 88]

We have built a garage that is 40' long x 20', with 5/12 trusses 24" OC for the entire length. The trusses span along the 40 ft. length.
My question: how much weight can I put on these trusses to use as a storage space above the garage floor. The garage also has 10 ft. walls.
Can I put plywood sheathing on top of the trussses so boxes don't fall through the spaces with items on the plywood?

[HayZee518]

I don't see why not! All there will be is dead weight on the trusses. In houses where trusses form the roof, there's walking boards installed for personnel.

[pushkins]

Like Hayzee suggested, you can store items up there BUT that doesn't mean it's limitless. The bottom cord of the truss isn't "specifically" designed to carry any great weight, it is designed to distribute load/weight from the roof down, the operative word here being "distribute", so just be sensible in what you put up there and how much you store in any one area.

[JUNEBUG 88]

Thank you, I have laid out the left over sheathing from the roof over the bottom chords so boxes do not fall between the openings. This should help in distributing the weight instead of on only one truss.
I am also limited as to how much I can lift up to the trusses as I need to carry the item up a ladder 10' up and maneuver it between the beams.

[HayZee518]

floor trusses and roof trusses are built in several forms. the wye-v form is the most common. the rafter part is supported by wye and v 2x3s laid sideways and fastened to the rafter and bottom cord that runs the length of the truss. its this bottom cord that carries the upper weight. in essence if you examine a truss diagram, you'll see that the bottom, because of all the weight is literally trying to rip itself apart. the truss depends on the intergrity of its wood fibers to stay together. this is another reason why they say NEVER to drill into the bottom cord of a truss.