Thread: New Construction garage roof trusses

These trusses were seen today in a single car detached garage. The bottom cord was spliced in the middle of each truss and truss plates were installed on both sides. The splice was directly down the center of the garage. It would seem to me that any heavy load stored in the attic of this garage would be a problem for that joint since there is no support under it. Am I over reacting here. Your thoughts please!

Thanks, Jim

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Originally Posted by JIM MURPHY

These trusses were seen today in a single car detached garage. The bottom cord was spliced in the middle of each truss and truss plates were installed on both sides. The splice was directly down the center of the garage.

This is quite common, and, provided the trusses where properly engineered, the trusses should be suitable for their intended use (no storage or limited storage) as per the required design in the code (I do not recommend, as a previous and off the wall poster did, that one presumes that the truss engineer did not know what they were doing).

It would seem to me that any heavy load stored in the attic of this garage would be a problem for that joint since there is no support under it.

Sure, one could throw a 50 ton electric hoist up there and lift their Sherman tank with it - but that is not in any standard design rating.

Am I over reacting here. Your thoughts please!

Yes ...

But then, I also did with K.W.'s preceding post, however necessary my explanation was for K.W., it was not meant as a comment on your question, only on K.W.'s response. Take care and have a good day, Jim.

Originally Posted by JIM MURPHY

These trusses were seen today in a single car detached garage. The bottom cord was spliced in the middle of each truss and truss plates were installed on both sides. The splice was directly down the center of the garage. It would seem to me that any heavy load stored in the attic of this garage would be a problem for that joint since there is no support under it. Am I over reacting here. Your thoughts please!

Thanks, Jim

2015-09-24 11.42.36.jpg2015-09-24 11.42.21.jpg

It is designed by an engineer. No addition loads should be induced.

You may not have noticed, but the ones in most attics are like that also.

And when necessary, I stand or step on the seam all the time, no issues....

Dom.

Thanks to all for your comments!

Jim

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Thanks to all for your comments!

Jim

Most truss members are designed mainly for tension or compression loading. However, truss connectors can handle bending. Assuming that the load does not exceed the design load there should be no problem. That is a common location for splices.

Originally Posted by Dom D'Agostino

You may not have noticed, but the ones in most attics are like that also.

And when necessary, I stand or step on the seam all the time, no issues....

Dom.

Originally Posted by Kevin Wood

Because of load bearing walls,they are fine in an attic.

(sigh)

Most trusses like that are clear span from bearing near one end to bearing near the other end - and there are no load bearing walls. Load bearing walls are common for conventional framing with sawn lumber. And, yes, I said "most" because there are trusses which require intermediate bearing points, but I also said "like that" because those look like they are clear span trusses.

Originally Posted by Kevin Wood

Because of load bearing walls,they are fine in an attic.

It is apparent that you know very little about roof trusses.

Hi Jim, thats probably a legit install even though it looks like crap.
On a side note, and forgive me if you already know, whenever I see something questionable I try to find a manufacturer label. That allows me to call the Manuf. and ask them directly. Amazing some of the great info you can get sometimes.

Originally Posted by Mark Reinmiller

It is apparent that you know very little about roof trusses.

Originally Posted by Kevin Wood

I guess that is why I see cracks in the middle of the ceiling on some inspections. I didn't know contractors were so stupid.

Kevin,

I know you are trying to show us just how much you know ... I want you to know that you have succeeded beyond your wildest dreams.

Originally Posted by Kevin Wood

I would love to challenge you in court.

I am sure you would love to, just like you've shown us how much knowledge you really have.

Okay. Let's keep it collegial.

The photos and discussion would lead one to surmise that the trusses are of fink-type ("W") design with the bottom chords center spliced using steel gang nail plates at the butt joints in the center of the two-piece bottom chords.

Multiple factors can come into play here. Assuming that the trusses weren't mishandled during transporting and placement, their design is currently accepted by the organizations which test and approve them. They fall under the general category of light weight construction materials. While not designed or intended for storing items on top of their bottom chords, placing things such as a few pieces of long lumber, holiday decorations, and other relatively low weight items typically doesn't adversely affect their performance. In fact, it's common to attach gypsum board to the underside of such trusses and to place insulation on top of ceiling material attached to their undersides without adversely affecting them.

A separate issue is the performance of steel gang nail plates under high temperature conditions. It's not uncommon to find truss joints separation in parts of the country where there are high temperature and low humidity conditions (Phoenix, Las Vegas, Tucson, etc.). When the truss lumber shrinks, the short gang nail plate spikes don't provide sufficient penetration (bite) and separation occurs. Also, during fires, the steel plates conduct enough heat into the wood such that the wood chars and the joints fail. Firefighters have been injured and killed due to this particular type of failure. There are always unintended/unanticipated consequences with new technologies. That's why it's always best to learn as much as possible and to keep up with new developments and research. Forums such as this one can be valuable in that regard.

Keep up the good work, everyone and remember, play nicely.

The trusses in my 3 car garage are virtually the same as those posted - a little better quality lumber and larger plate perhaps, as is my neighbor's across the way. I saw him working on his double car roll up door a week or two back and asked what the problem was. For some reason ( his words) his automatic door had failed and the door had slipped of its tracks. He is an auto mechanic and his son an avid race car driver...they had stored spare wheels, tires, engine blocks, jacks and tools on plywood shelving, spanning the bottom chords. Everything across the width of the span over the double doors had bowed downwards from all the weight, causing the door tracks to spread apart. Not a cheap fix by any means.

Originally Posted by Ian Page

He is an auto mechanic and his son an avid race car driver...they had stored spare wheels, tires, engine blocks, jacks and tools on plywood shelving, spanning the bottom chords. Everything across the width of the span over the double doors had bowed downwards from all the weight, causing the door tracks to spread apart. Not a cheap fix by any means.

He could have broken things with heavier trusses as heavier trusses would have let him store more in them.

"It would seem to me that any heavy load stored in the attic of this garage would be a problem for that joint since there is no support under it."

It seems to me that you are right...don't use it for storage.

Originally Posted by Chris Weekly

"It would seem to me that any heavy load stored in the attic of this garage would be a problem for that joint since there is no support under it."

It seems to me that you are right...don't use it for storage.

Don't use it for storage in excess of the storage it is designed for - it may very well be designed for 'storage', just not for storing race car wheels, tires, engines, transmissions, concrete blocks, bags of concrete mix, etc.

Personal responsibility needs to be taken into account - store some 'normal' attic storage items and no problem, store the Hummer up there and, yeah, it will likely fail.

The codes now call for higher load rated trusses to accommodate attic storage when the area and height meet specified requirements - but those higher rated trusses still do not take into account those 'unusual' things being stored in the attic.

Right...so...the owner, tenant, occupant will abide by the engineered or maximum permissible load. Do they have a clue there is such a thing?
Probably less knowledge of truss loads than the construction crew who stacked the trusses...and they were supposed to abide by the 114 page manual for installing trusses.

"I doubt anyone I've seen installing trusses has ever looked at, much less actually read and understood the requirements for handling metal plate connected wood trusses:
- http://support.sbcindustry.com/docs/...nfio8j0p9515d2"

So when it comes to storage in the garage framing I suggest cardboard boxes or empty suitcases ...no car engine hoists, engine blocks or transmissions, or anything larger than a bread box.

Chris,

When someone lacks the common sense to NOT store really heavy items in the attic ... well ... you can't fix stupid.

Sometimes stupid fixes itself, such as a redneck's last words ... 'Hey, Bubba, watch this ... '

Yup...
I had to throw in the extra two dots on this message. It was too short otherwise. Brian does not want a senseless remark to go out on the Inspection News wire.

On several occasions I have taken a look at what was stored in the open space above a garage and found engine blocks and transmissions.
Generally, I'm surprised and say something like "Holy Smokes, there's an engine block up here!" to which the homeowner will reply "Yeah! You can't believe how hard it was to get it up there".

I have never replied "Duh", but have seriously wanted to. As a result, I have a standard comment warning people about storing stuff in attic and above garages. As we all know, you can warn 'em, but who knows if they listen?

Originally Posted by Gunnar Alquist

Generally, I'm surprised and say something like "Holy Smokes, there's an engine block up here!" to which the homeowner will reply "Yeah! You can't believe how hard it was to get it up there".

I would probably respond with something like 'Yeah, there is probably a reason for it being hard to do ... like ... it shouldn't be done ... ' then turn and walk away shaking my head side-to-side and whispering to myself ... 'Stupid is as stupid does' ...

Originally Posted by Gunnar Alquist

Generally, I'm surprised and say something like "Holy Smokes, there's an engine block up here!" to which the homeowner will reply "Yeah! You can't believe how hard it was to get it up there".

Wow! You gotta laugh at some of the things people do.
Well, getting it down may be easier...mattress on the garage slab and a heave ho.
I often will ask the seller to move all the things in the attic so I can have access. Most just give me a goofy, confused look. Is this guy serious? Yeah, at least I asked in front of the buyer...limited inspection.

Originally Posted by Chris Weekly

I often will ask the seller to move all the things in the attic so I can have access. Most just give me a goofy, confused look. Is this guy serious? Yeah, at least I asked in front of the buyer...limited inspection.

A good response with the attic shown in your photo is to the effect of 'Well, see that paper facing on the insulation ... (they nod that they see it) ... I need to see just how much of the attic has that exposed paper facing ... because NONE of that paper facing is allowed to be left exposed.'

Yup...(again with the dot, dot, dot)
anyway, sure. I told them about the insulation facing and will include a photo of the warning on the facing paper.

- - - Updated - - -

oh, and all that heavy storage - legal files filled to the brim, and lots of 'em, has caused the kitchen ceiling below this to bow under the weight with stress cracks in the drywall. No engine blocks that I could see.

With a lot of paper stored, you really don't need an engine block, that's for sure.

Roof trusses are generally intended to carry only the load of a dry wall or plaster ceiling and the weight of insulation commonly used in the area of manufacture. Unless specifically designed for storage nothing should be stored in the attic. That means no artificial Christmas trees, engine blocks or transmissions etc.

- - - Updated - - -

Roof trusses are generally intended to carry only the load of a dry wall or plaster ceiling and the weight of insulation commonly used in the area of manufacture. Unless specifically designed for storage nothing should be stored in the attic. That means no artificial Christmas trees, engine blocks or transmissions etc.

Originally Posted by Don Hawley

Roof trusses are generally intended to carry only the load of a dry wall or plaster ceiling and the weight of insulation commonly used in the area of manufacture. Unless specifically designed for storage nothing should be stored in the attic. That means no artificial Christmas trees, engine blocks or transmissions etc.

Roof trusses which have storage space in them (some have space which permits storage, others do not have any practical usable space within the truss design) are typically required to be designed for storage at, as I recall, 40 psf.