garage trusses 1

[gursh]

i have 9'7" celling in the garage, where i need to install a hoist,
i need to cut 2 or 3 trusses ,is this possible i would like some advise , there must be a way to support 3 trusses

 

[Ron]

You need to explain what you're doing better. That's not enough information for anyone to give you any reasonable advice.

 

[msquared48]

You really need to engage the services of a local structural engineer here rather than lose the roof of your garage.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[MiketheEngineer]

As Mike said - get a good Structural versed in wood trussses. Dependng on the loads you wish to lift - say a car engine or tranny - the original trusses may have have "enough" over design in them to do the trick. BUT it must be checked!!

 

[gursh]

I should be more clear as to what i on tend to do
1) there is going to be no load what so ever pulling down on the trusses
2) I just want to cut a section out may be 5x10 section, so that when I lift a vehicle up with a 2 poster car lift , the roof of the car goes into the celing of my garage ( as i do not have the height)
the trusses are at 2 ft on centers with a span of 22 ft in length
there are verticle suppports to which I can give measurements
the lenght on the garge is 24 ft approx
So I will need to cut away at least 5 trusses at the main cord

Is this possible by supporting from the ground with metal vertical beams/ Jack supporters so without constructing whole new trusses which would mean tearing the roof off and starting fresh?

 

[Ron]

OK...now you've explained your issue. Get a structural engineer involved. What you are proposing is dangerous.

 

[MiketheEngineer]

How high above the bottom of the bottom chord do you need.

It is possible - but probably rather labor intensive and may be a bit expensive

Get an engineer well versed in wood truss design

 

[gursh]

thank you very much..just to make it more clear i made a rough diagram hope it makes sense and if you can give me some idea if it is possible.
the centre is 2ft

 

[woodman88]

I would go to a local truss manufacturer and have them design and build some truss frames to nail on the side of your existing trusses. Then you can cut the existing trusses up to the frame and get the height you want.

Garth Dreger PE
AZ Phoenix area

 

[msquared48]

If you cut the bottom chords of the trusses as you propose, the roof WILL fail... guaranteed. Grt the structural engineer. End of story.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[SteelPE]

grush

I have pictures of the exact thing you are proposing. I had a client who cut out the bottom chord of some trusses so he could fit his car lifts in. However, I was not there to investigate the possibility of adding a car lift, I was there to replace the roof because the roof collapsed after he made the modification without consulting an engineer. Luckily nobody was hurt in the incident.

Again, what you are proposing is extremely dangerous. Hire a structural engineer and you will be able to sleep at night.

 

[omoreno1]

This sounds like a bad idea without consulting a structural engineer. Cutting truss bottom chords will affect the tensile capacity of the truss bottom in gravity loads, and will also affect its compression capacity in uplift mode. Anytime you cut a truss consult a truss engineer, they can pretty much design anything.

 

[Splitrings]

gursh,
I agree with woodman on this one. There are nearly a limitless number of different truss types that you could sister to your existing trusses. Scissor, cathedral, scissor with horizontal tie,... The difficult part would be getting these trusses in place before you cut the bottoms of your existing trusses.

 

[gursh]

Thanks to all
I would not cut off any trusess until I have a support for it
the many cord is 24 ft with verticle angled support at 8 ft I have involved a roofing company that claim they have modified roofs such as mine
if I can get drawing as to where and what angle a support is needed then place the support in it's place I would cut one by one out creating my opening I need if I was to give the correct measurments of all the cords is there a possibilty that some one could provide me with the details I need to support my roof ?

 

[Ron]

gursh...someone could provide the detail you want but not someone on an internet forum that has no idea where you are located, what type of truss configuration you have, the loads that are currently on the structure or the loads for which it must be designed.

Don't get a roofing contractor to make structural modifications to roof trusses!! Let me repeat that...Don't get a roofing contractor to make structural modifications to roof trusses!! In most states that is beyond the license scope of a roofing contractor and therefore illegal.

What you want to do is convert existing trusses to a "tray" ceiling configuration. That's easy to do when the structure is built, but not so easy to do as an in place modification.

For all of those who have said it before in this thread, I'll say it again...GET A STRUCTURAL ENGINEER INVOLVED!!

 

[ComponentsDesigner]

I agree with the others. We have done many modifications to existing trusses and what you are wanting to do is possible.......BUT, only after a Structural Engineer has reviewed, and designed Scab trusses and possibly overseeing the work. Find out who originally manufactured the trusses, speak with them. I am sure that they would be able to assist you with this...for a small fee of course. If you or a roofing contractor make any modifications to the existing roof truss without the consultation of an Engineer YOU will be liable for ANY failure/injuries/Deaths that may occur. I doubt your Insurance company will cover it. Just my 2 cents.

 

[gursh]

i have attached a diagram to explain may be some body understands it with measurements they are with 5inch
i have 5 truses that need to be cut 5ftx10ft
5ft length of the main cord the cords are 2ft apart so 5 of the will give me 10ft.

 

[Ron]

gursh...I don't mean to be unkind, but you seem intent on doing something stupid. You obviously don't understand how the truss works or the distribution of loads within the truss. This forum won't teach you that.

You've been advised by people who have many years of experience with this. We've seen what happens when someone does what you are proposing without adequate preparation, analysis, and safeguards. The result is not pretty and can be catastrophic, resulting in injury or death.

Get some local help with this from a structural engineer or truss engineer before you kill yourself or someone else.

 

[efsinc]

amen