STORAGE – On the trusses – good or bad?
toolbear
| Posted in Construction Techniques on
Folks,
A friend has a question. His garage has a truss roof with drywall lid. Span is about 24ft. The previous owner installed a pull down attic stairs unit.
He wonders how much stuff he can store on the trusses in the garage.
Currently it is light stuff along the edges.
Is is a smart idea to lay down some OSB decking and get more serious about storage space?
I have no idea what the static load rating is on these, but I am sure someone out there does. Hey, we walk on them and install FAUs up in them. Can he put his bowling ball colletion out in the middle?
Replies
Standard trusses will take very little extra load safely. The truss company can give you the exact #/sf.
Locally this summer we had an example of why not to load the garage trusses.
A gentleman moved into his new house several years ago and converted his garage into a shop, in which he spent most of all weekends "doing his thing". The pull down was convenient and the attic space became his archive of treasures and leftovers.
On the day of the accident, the HO decided to do something other than his normal "day in the shop"......he & DW went on a day trip.
They arrived back home to find the weight of the stored materials had collapsed the trusses into the garage and blown the garage door out into the driveway along with lots of his stuff!
If you want to have good safe storage....have it engineered.....otherwise avoid stacking on the bottom chord of the trusses you describe.
Boss Hog can/will chime in strongly on this matter.
................Iron Helix
oh sh!t Oh sh!t I got a buddy.
Man, now that you mention it.
I mean I never even thought about it.
He got ahold of a whole slew of planed 8 and 10foot long 6and 8inch wide oak from somewhere.
And now that I think about it, guess where a worker of his decided to store them?
Guess I better make a call. Thanks.
"Standard trusses will take very little extra load safely. The truss company can give you the exact #/sf.
Locally this summer we had an example of why not to load the garage trusses."
@@ Bet the wife shared her thinking on that issue. Wonder how the roof is doing without a bunch of bottom chords. I believe they also serve to tie the walls together.
Retrofit solutions...
The followup question is, if you can't load the trusses, what would you need to do to convert that space to properly engineered storage? They don't seem too keen on Lally columns. Something about opening their car doors. Picky!
"Why can't we take out the basement posts and make a BIG rec room?"
The HOs sure do like the clearspan! What do you mean "loading"?
As for your question....not that there might be a solution, but to attempt it there needs to be more info.
Spans, pitches, loading, ceiling/wall height, truss configuration, additional roof loadings, drawings, and customer budget limits.
If your local truss company has a rep that likes challenges and has half a brain...call him out for a look-see for a computer generated fix. $$.00
Or....Send all this to an engineer for a retro fix on the existing trusses to gain some serious storage. $$$$.00
Maybe rip off the garage roof and redo it with a new set of room-in-attic trusses, resheath and reroof. $$$$$$.00
An addition at garage floor level! $$$$.00
Sell the house and move to another with bigger storage capacity. ;>}
Maybe it's not a feasible project?!
..............Iron Helix
what would you need to do to convert that space to properly engineered storage?
Probably TJI from top plate to top plate, not attached to the joists (like midspan between), with the storage deck over them. TJI may seem a bit like overkill, but by the time you get to 30# storage loading and a 24' span, dimensional lumber will be close in price if not dimension. Fishing TJI into the attic will be a chore--but so would dimensional lumber.
You could add beams underneath, but that will require a lot of engineering. The trusses would need recalculating, and you'd likely need a fancy bit of engineering for where the beams hit the door header.
(Had to put a beam in my Dad's garage, 2x6 @ 24" OC spanning 26' was barely enough to carry the DW, let alone the 550 SF of 1x3 diagonal attic decking.)
That much effort makes popping the roof & existing trusses, then replacing with correctly designed seem a lot more feasible.Occupational hazard of my occupation not being around (sorry Bubba)
The technically correct answer is no, you can't store stuff in the trusses unless they were designed for added loads.
But realistically, you have a fair chance of getting away with it if you're careful. But careful doesn't include keeping a bowling ball collection up there. Careful means light boxes of stuff spread over several trusses.
There's no way any of us could know if trusses are designed for additional loading without checking them out. Storage trusses may have a 2X6 bottom chord and/or oversized plates. Or maybe just higher grade lumber in the bottom chord. Depends on the truss company and how they typially design them. Everybody does it differently.
If the house is new enough, you might be able to get the info from the truss company that supplied them.
There's a new plan under consideration for airline securirty - They're thinking about hiring soccer Moms to be stewardesses
These look like very stock trusses. 2x4s, nothing oversized. So, adding flooring and such is Bad Career Move.
I don't think the documents survived construction back when.
The important thing to understand is that these 2x4 bottom cords were designed to be in tension only. Their main purpose in life is to keep the building's walls from spreading due to the lateral loads that would otherwise be imposed by the "roof rafters" (truss top chords). The bottom chords are likely designed for very little to no live load. Another way to think about it is this: most span charts don't even list 2x4s in the floor joist section; or at least none that I have seen. Matt
"...these 2x4 bottom cords were designed to be in tension only."
Bottom choards are designed for both tension AND bending forces. Otherwise you wouldn't ba able to ahve a ceiling attached to them.In my house on the ceilings I have paintings of the rooms above... So I never have to go upstairs.
Hey Boss, do you install trusses and rafters? How do the installations costs compare? Just make up a fictional comparison... just a basic gabled roof, nothing fancy.
I tend to work on older houses, and they tend to have rafters. Seems like such a waste of space when I crawl into a newer house's attic to find the entire space taken up by trusses. I realize they make special-order trusses that give you room for a room in the middle, but are rafters that much more expensive?
In our thread here, a garage with a sufficiently high roof made with rafters would be a better candidate for 'upstairs' storage.
jt8
Yes, I've installed both rafters and trusses.
But to do a comparison is all but impossible. Might be worthy of a thread of its own, if you want to start one. Although it might escalate into something like the old venting wars. (-:
The Wood Truss Council built 2 homes side by side a few years ago, and kept track of the time and cost of materials on each. One ws stick framed, and the other built with trusses and panelized walls.
There are some PDF documents about it at:
http://www.woodtruss.com/projects/woodtruss/images/publication_images/fad.pdf
http://www.woodtruss.com/projects/woodtruss/images/publication_images/fadrf.pdfI took an I.Q. test and the results were negative.