Garage Ceiling Storage Load Capacity 19' Span - Help

[maxxeddiy]

So I installed 4 x 8 storage racking in the ceiling of my garage (19"x20"). I put two above the garage door and two more in front of them to create a T.

I think I have the terminology right feel free to correct. You will see below how the garage is layed out with the storage from overhead. I tried to keep it as close to scale as possible.
- Red is the storage racks
- Green is cinderblock
- Dark red is the garage door
- Blue are the trusses with the thickness marked
- Yellow dots are the mounting points to the trusses
- Pink dots are the mounting points to the wall

This is what it looks like in the attic

Installed

Any help or feedback would be appreciated.
The question is what kind of weight limits should I enforce. The racks weigh 75lbs each so I already have 300lbs up there. Is it safe at all,.. should I move them or take them down?

Other info,... we are in Florida so no need for snow planning,... and the roof is a tile roof.

Thanks!

 

[akdiesel]

Your truss system is hell for stout, and since your garage is only a standard 2 car size garage you could park a tank up there. But I am not an engineer. This is only my visual observation. Your layout does not match what your pictures show. they look like 2x8 with 2x6 cross sections as well as sistered together with double and quad trusses.

 

[Onewolf]

Your truss system is hell for stout, and since your garage is only a standard 2 car size garage you could park a tank up there. But I am not an engineer. This is only my visual observation. Your layout does not match what your pictures show. they look like 2x8 with 2x6 cross sections as well as sistered together with double and quad trusses.

I might disagree with that assessment. Assuming the OP was accurate in assessing 2x4 vs 2x6 vs 2x? then most of the racks are mounted into the 2x4 bottom chords. 2x4 bottom chords don't provide much dead load capability at all. I'm an engineer. Just not the right kind. I'm a software engineer. I would want to see the truss engineering documents.

 

[bczygan]

Your tile roof is a heavy roof. That is why your trusses are stout.

Whether they are designed for substantial additional loads is a question for the manufacturer. Likely there is enough of a safety factor built in that failure is not likely for what you are now doing. You might notice light cracking and nail pops in the drywall though, if loading causes deflections above design.

It really depends on the initial design, size and strength of materials. Are they made of SYP? Are those little white squares on the photos stickers of some kind?

What I have a question about is the quadruple truss. Is there a wall above that for a second floor room?

 

[maxxeddiy]

Humm,.. I am probably just referring to it correctly. I work in IT so this is all new to me. I can engineer you a complex Visualization Strategy for your backend computer systems,.. but structural engineering is not my deal

The heavy bottom chord (4ply) in the middle measures 6"x6". The medium bottom chord behind it (2ply) measures 3"x6".

Full disclosure 20% of that diagram was from memory. I may need to take more pictures.

I figured I would get a jump on it this morning in case there were any major issues.

 

[maxxeddiy]

They are stickers I couldn't make them out from the original crawl space. I will have to get closer and check them out.

I called the builder first and they said that due to Hurricane building code changes their "official word" is that the ceiling is to hold the drywall in place. The rep was honest and said that he personally stores items (off the record of course). It seems like it is just a CYA from the builder.

It is a one story house,.. no second floor.

Thanks for the feedback so far guys!

Your tile roof is a heavy roof. That is why your trusses are stout.

Whether they are designed for substantial additional loads is a question for the manufacturer. Likely there is enough of a safety factor built in that failure is not likely for what you are now doing. You might notice light cracking and nail pops in the drywall though, if loading causes deflections above design.

It really depends on the initial design, size and strength of materials. Are they made of SYP? Are those little white squares on the photos stickers of some kind?

What I have a question about is the quadruple truss. Is there a wall above that for a second floor room?

 

[maxxeddiy]

I might disagree with that assessment. Assuming the OP was accurate in assessing 2x4 vs 2x6 vs 2x? then most of the racks are mounted into the 2x4 bottom chords. 2x4 bottom chords don't provide much dead load capability at all. I'm an engineer. Just not the right kind. I'm a software engineer. I would want to see the truss engineering documents.

That was my main concern,... this area:

I thought about a "sistering" the bottom chord,... or running 2x4s in the opposite direction to distribute the load across a 3 2x4 chords. Another option was to swing the back storage racks around so that they are mostly against the wall.

I thought I should get outside advise before I make any more changes.

 

[Krash Kadillak]

No-degree guy talking here:

Looks sturdy enough for me. My only question is how you attached the storage system vertical supports to the trusses......

 

[maxxeddiy]

No-degree guy talking here:

Looks sturdy enough for me. My only question is how you attached the storage system vertical supports to the trusses......

The racks came with (for lack of the official name) giant screws with bolt heads on them. Looked to be about 1/4" by 3".

 

[maxxeddiy]

I am thinking the 4ply truss may extend the width of the house. The front office and garage stick out. You can see from the aerial how it fits in line with the main portion of the structure:

 

[Jfresh]

Trusses are engineered according to roof load. The strength comes from the load pushing down from the top, Not pulling down from the bottom chord. Thats is why they can be built just holding them together with the metal plates. It might hold your racks but that is not what it was designed for.

 

[machsnell]

You are fine.