Modifying an engineered truss

[71buickfreak]

Long story short, I ran out of money when we were building the new shop (50x30x10) and we built it 10' rather than 12'. We made an area that was 15-long on the 50 length, so basically we dropped 2 trusses (trusses are on 5-foot centers). That is where the lift goes. It is 15-foot long, but I have several vehicles that are longer than that and whe I can get the lift up enough to work on them, it is a challenge. I am thinking about modifying one truss to allow me an addition 2-3 foot of vertical lift. These are modified Queen trusses. I am looking for suggestions on how I can increase the space above the lift safely. I can use steel or wood to reinforce the existing truss.

 

[DekeT]

This thread will quickly turn into the usual groups who tell you how to cobble up some boards to the trusses and say the safety nazis are whimps versus those that will tell you it is an engineered truss for a reason and you will drop your roof if you screw it up.

What did the truss manufacturer say about modifying the truss?

 

[71buickfreak]

I have not contacted them. I'd have to find them, the building was put up by a contractor.

 

[cyamaha2007]

That looks like your is done "by spanning a bay" I dont think you could modify either side of that system without redoing the in between ceiling purlins.

 

[71buickfreak]

My thought was to do what I have outlined in the drawing here. Thoughts?

The added panels would likely be added to the existing truss as sandwiches, a new board on both sides of the existing boards.

 

[DekeT]

My thought was to do what I have outlined in the drawing here. Thoughts?

The added panels would likely be added to the existing truss as sandwiches, a new board on both sides of the existing boards.

Well, what does the truss manufacturer say about that plan?

 

[71buickfreak]

It's sunday, I can't ask them yet.

 

[mrobins297aaa]

I wouldn't modify that truss without a engineers approval.
I know this is hind sight because you stated that you already have the lift in place, but why didn't you turn the lift the other way? (90 deg) then you'd have plenty of room or if you move the lift closer to one end,(one of the supporting trusses in your 15' span) as long as you drive the cars/trucks on from the same direction you would have the hood of the vehicle under the 10' truss and with a ten foot bot of truss that would be plenty of height.

 

[71buickfreak]

Because of the way my shop is laid out, that would block the rest of the shop.

 

[71buickfreak]

Plus, I would have to add a side door.

 

[volaredon]

looking at something similar though mine is entirely stick built (no trusses) and 16" OC. I won't hiack here though.

 

[mrobins297aaa]

where is your lift mounted? is it right in the center of the 15' span? and what kind of vehicles are you lifting?

 

[NHBandit]

Also what's your location ? Is heavy snow load an issue ? I tend to be one of those guys who will wing it and the engineers can KMA but if you modify it yourself and the roof caves in you'll play hell getting any money out of your insurance company.

 

[LutzTD]

the section where the 3 members meet on the right side looks weak to me. If it were me Id ask rather than have it come down around if Im wrong

 

[Abj87]

The bottom member is in tension, cutting it would compromise the structure.

 

[71buickfreak]

I live in Central Oklahoma, we do get snow, but not heavy snow. Wind is the biggest issue here.

I am hesitant to do anything, I am not jsut going to go crazy and hack it all up. Anything I do will be done with the new structure in place before I cut the existing beams. I just need a couple of feet. I mostly have muscle cars and wagons. The wagons are low but long, one is 20 foot. I also have a couple of trucks. The original plan was to run the lift along the 30' side, if I did that, it would be no problem, BUT getting cars into the rest of the shop would be.

 

[wssix99]

My thought was to do what I have outlined in the drawing here. Thoughts?

The added panels would likely be added to the existing truss as sandwiches, a new board on both sides of the existing boards.

This design of the truss will definitely fall down - but the manufacturer should be able to give you a plan that will work. (They do this all the time for trusses, which are damaged in the field.)

 

[DekeT]

I tend to be one of those guys who will wing it and the engineers can KMA

It's great you are git er dun guy but I fail to see why you need to malign engineers. I find it personally offensive.

 

[tc-cad]

How about this. Ask for a quote (from a building center or truss mfg) on a new truss that will be high enough (maybe cathedrial ceiling in the area you need it) for what you want and then compare that design to your existing truss? You can then make some educated decisions as to what will or will not work.

 

[ydna]

This thread will quickly turn into the usual groups who tell you how to cobble up some boards to the trusses and say the safety nazis are whimps versus those that will tell you it is an engineered truss for a reason and you will drop your roof if you screw it up.

good call.

 

[stonewellmark]

Im gonna tell you what I would do....right or wrong " I feel" its plenty strong enough. I would sandwich the existing truss with 1/2 plywood (both sides, the entire truss), then cut out where you need the space. After that is complete, cut the appropriate 2x material: 2x6 bottom runner, 2x4 vert/diagnals) and install them in between the plywood wherever there is a void. The plywood then becomes the truss, except where it sets on the wall and that is why you would attach the plywood the existing truss before making any cuts.


Mark

 

[71buickfreak]

I called the truss company, it will cost me around $500 to have them draw up a modified truss.

 

[ovilla]

Call the truss company again and ask for the pricing for 2 scissor truss halves, plus any additional hardware Taft is needed to be able to install them as a retrofit set up,. You should be able to lift and nail (to the existing truss) each half truss into place and then cut out anything below the new scissor truss halves. This will give you half of your attic space for your lift and should be easy to install from inside the building too.

 

[71buickfreak]

I like that idea. ^

 

[95vette]

Hello, Stonewellmark has it right in post 21, just be sure to use construction adhesive along with screws or nails and it will never move with what little you want to cut out.Jim

 

[stonewellmark]

What 95Vette said! Stronger than whats there now. Also, pre-load the truss (center)with a floor jack and post, just a little, before installing plywood. That way when you remove jack after plywood is installed it will "settle" under the new "static" load of the plywood.

Mark

 

[tc-cad]

Another Idea: Go to your local college Engineering Department and ask them to engineer you a solution. These guys would love real life experiences.

There must be software that also can do this? I just Googled it and there is. Also a free download trial version.

 

[willymakeit]

I agree with Stonewall. We use to mpdify truss's this way. Especially old bow truss's. Plywood makes the complete truss work and simply ties everything together.
Extend the plwood out over the top of your walls following the outline of your truss. Add members inside the truss at the plyood joints and stagger either side of the truss with plywood.
Get a engineers stamp if you need one for future issues.

 

[V-10 Killer]

My thought was to do what I have outlined in the drawing here. Thoughts?

The added panels would likely be added to the existing truss as sandwiches, a new board on both sides of the existing boards.

I had my trusses designed close to that from the manufacturer when I built mine.

But they did all the calc's and beefed it up where they knew the load stresses would be. Definately check with them, but your drawing is close. I'd say go all the way back to the centerline of the truss though, not a few feet out.

 

[umtallguy]

seriously just buy a sissor truss it will cost like200$ if its a standard size ...