Wanting to modify existing trusses for lift

[Nnorman1]

I’m wanting to modify my existing trusses in my 30x40 barn to make enough clearance to lift up 3/4 and 1 ton trucks:

I’ve seen several posts on here of people modifying some smaller barns for the same reason but not any this size atleast, wanting some help/tips on how to do it and can it be done?

 

[billconner]

Would replacing the trusses in the section you want higher (20' of 40'?) with scissor trusses give enough height?

 

[readhead]

What is the existing condition compared to what you want? Photos would help.

 

[Nnorman1]

Would replacing the trusses in the section you want higher (20' of 40'?) with scissor trusses give enough height?

Ya I’d think so, but can you put scissor trusses in and cut out existing truss out of the way? I’m not sure the best way to go about it

 

[Nnorman1]

What is the existing condition compared to what you want? Photos would help.

Sorry I thought I posted a pic it must’ve not went through

 

[Nnorman1]

 

[readhead]

Still don’t know what you need. Six inches, two feet? Is a snow load involved? Permit required? How many trusses?

 

[theoldwizard1]

... wanting some help/tips on how to do it and can it be done?

The short answer is, NO, it can not be done cost effectively !

If you proceed with un-approved plans, your insurance company will not cover any structural failure. You may even be liable AFTER SELLING !

 

[billconner]

if trusses are 8' on center, can you orient lift to be between trusses? Won't your vehicles fit in 8' when lifted? It seems doors are in eave wall not gable so thats goid. It should be possible to clear any framing between lower chords of 2 adjacent trusses. It probably needs truss company or engineer to say what has to be added, but should not be hard.

Sorry, are the trusses 8' on center? If not, replace 1 with 2 that are and add purlins be on edge.

 

[Garcky]

I wouldn't make any changes in that building without consulting a structural engineer. It's not over-designed by any means, so it depends on its structure too much to make random changes safely. To me, it already looks over spanned and somewhat sketchy. Get some professional advice, I think.

 

[Spud McGee]

Your existing trusses are along the 30' direction? I'd think you could install new trusses directly beside the existing ones, then cut the existing ones out. You could even install more trusses, closer together than the one's you're replacing. But I'm no structural engineer.

I was going to suggest steel trusses. But the ones I'm using need a foot of room to drop down below the mounting point. Your roll up door would prevent these sort from fitting there.

 

[Nnorman1]

Your existing trusses are along the 30' direction? I'd think you could install new trusses directly beside the existing ones, then cut the existing ones out. You could even install more trusses, closer together than the one's you're replacing. But I'm no structural engineer.

I was going to suggest steel trusses. But the ones I'm using need a foot of room to drop down below the mounting point. Your roll up door would prevent these sort from fitting there.

Ya 30’ wide (direction of the trusses) and 40’ long

 

[Nnorman1]

Still don’t know what you need. Six inches, two feet? Is a snow load involved? Permit required? How many trusses?

Like to get as much clearance as I can on two trusses, not a very big snow load where I’m at normally. No permit needed I don’t think but not sure how that works.

 

[sjvicker]

start googling and find a structural engineer in your area. A good starting point may be a truss company that can point you in the correct direction.

At a minimum I'm guessing that what you would end up with is adding a new truss on the post next to the roll up door that we can't see in the photo and bridging between that new truss and gable wall truss with 2xX's on ends and connected with joist hangers. Expect to pull off your roof metal in this area to do the truss swap and add the new perlins. Assuming you already have a post on the hidden side of the garage door and the engineer lets you connect to it using assumptions about post depth.

 

[Zeke]

I'd like to see someone raise, roll in and attach a new truss under an existing roof.
Why don't you just put some temporary posts under the ridge and cut the bottom chord?
When you get done prepare for the inevitable sag.

 

[firebirdparts]

You may not need a permit, for instance, modifying a farm building, but you'll surely need lots and lots of competence. This question gets asked here a lot, and in a case like this, I think you want to beef up a truss on each side, beside what you want clear, beefy as is competent, and then reach purlins across the truck. There are lots of ways to build a building, but that seems cheapest here to me.

If you support the roof from the floor, then you can effectively build whatever you need up there, and that should also be pretty obvious to a reasonable and skilled person that support from the floor would be necessary if you wanted to take a truss down to make room for whatever you want to do.

 

[readhead]

This isn’t “good guess” territory. I would want an engineer to assess the situation and propose a solution. As someone mentioned there is a strong likelihood that the roof may have to come off to do the work.
I have been involved in some similar jobs where we came in and provided temporary shoring so the new work could be installed. In both cases additional trusses were added to the existing trusses to create girders and new larger purlins were added between the new girders. The roof had to be removed to crane in the new material. This was all accomplished and dried in in two days using our crane. Not difficult but also not inexpensive.

 

[PoorUB]

IMO, you need to order a couple properly engineered scissor trusses, open up the roof, remove two of the standard trusses and replace the roof.

Nothing to it!

 

[CraigStu]

I am thinking that an engineer could design a new scissor truss that could be built in place. If you lay a diagram of a scissor truss over a diagram of the existing truss it seems one could build the scissor truss in place and then remove the excess pieces of the original truss. One could even build double scissor trusses, one each side of the existing truss.

 

[billconner]

Probably the least expensive solution are columns and beams. Without a plan and section hard to say the best arrangement but two posts and a ridge beam, and replace top chords of trusses in that section with beams would be a pretty direct approach.

 

[Nnorman1]

I'd like to see someone raise, roll in and attach a new truss under an existing roof.
Why don't you just put some temporary posts under the ridge and cut the bottom chord?
When you get done prepare for the inevitable

I am thinking that an engineer could design a new scissor truss that could be built in place. If you lay a diagram of a scissor truss over a diagram of the existing truss it seems one could build the scissor truss in place and then remove the excess pieces of the original truss. One could even build double scissor trusses, one each side of the existing truss.

I’ve seen some people do it on YouTube but didn’t know if anyone on here has or if it’s a good idea or not