Vaulted Ceiling Truss Suggestions? Tall Pitch

[scootermcrad]

Hey everyone!

I'm excited that I finally get to ask a question relative to planning a garage build!

Pretty far out from building the new garage/shop. So, I'm doing some serious planning in the mean time to get all my ducks in a row.

The main portion of the garage has a 24' x 36' foot print (3-bay) and will have a 12-12 pitched roof to try and match it up to the house. At one end of the garage, over one of the bays, will be a loft/mezzanine for storage.

For the other portion of the garage over the other 2-bays I would like to have a vaulted ceiling of some form so I can eventually put a lift in and because I'm going to be running an I-beam trolley along the ceiling so I can lift engines, bodies, equipment, ect., up to the storage area. So it would be a 36 foot long beam and trolley system, essentially.

The question is, what truss design for the roof? I'm thinking a double inverted style truss so the I-beam can be as high as possible so I can transfer the hoisted load right into the loft/mezzanine area. This would also give me that vaulted ceiling I'm after as well as a nice open feel.

The concept I was thinking of. Sort of a crude sketch. But I think you guys get what I'm thinking...

The area where the loft/mezzanine is will be structured slightly different, to allow for more storage. There will also be a dormer on the front and rear of the roof at that area. So mostly I'm concerned more about the open portions.

Obviously there is a certain visual effect I'm going for here, besides just the structural aspect. Option A is sort of straight forward, I think. Option B adds in a little extra "drama" with the curved piece at each trussed section. I-Beam would hang below the peak and would also be supported at either end of the span.

Also thinking about building these myself. Peak height above the start of the pitch is 12 feet, or so. That would give me about a 17 foot roof face on that side of the truss.

Thoughts? Suggestions? Pictures of similar ideas? Tips for constructing the trusses and keeping a nice visual appearance?

Thanks guys!

 

[jbs]

I hate it when people give this type of answer, but this seems like something that really needs to be engineered. I wonder though if it wouldn't make more sense to run your I-beam just under the peak of your trusses, and have it independently supported at its ends (so it is not the trusses that support your trolley/load). And if you are doing that (carrying the load down at the ends anyway), perhaps you could use a ridge beam (either the I-beam itself or a glulam riding on the I beam) to support rafters (16 ft span should be easy) and dispense with the trusses altogether. Just a thought...

 

[Xander]

I did mine like this, with a scissor truss, however mine is a 32 x 24 2 bay garage.

It's not 100% clear, but you should be able to get the idea. I get the point of hoisting things, but I don't feel like that truss design would hold a lot of weight. Mine is only an 8-12 pitch on the roof side, and a 6-12 on the inside, but that still gets me 5' higher than my floor.

I like the hoist idea though, maybe I'll put a small beam up there to make this work for my storage area.

x...

 

[scootermcrad]

I hate it when people give this type of answer, but this seems like something that really needs to be engineered. I wonder though if it wouldn't make more sense to run your I-beam just under the peak of your trusses, and have it independently supported at its ends (so it is not the trusses that support your trolley/load). And if you are doing that (carrying the load down at the ends anyway), perhaps you could use a ridge beam (either the I-beam itself or a glulam riding on the I beam) to support rafters (16 ft span should be easy) and dispense with the trusses altogether. Just a thought...

I appreciate any and all ideas and input. And I agree, it should be engineered and will be. I'm an ME myself, and I have a good structural PE friend in the family, so he and I will be going through the calculations.

Since roof structures are not in my daily scope of work (or EVER, for that matter), I'm not about to just assume that if mathemtically works that it makes sense from a construction standpoint.

My thought was that I would probably have to have a pretty heavy ridge beam to bolt to, but provide additional support for the ridge beam itself and potentially 6x6 structural square tubes at each end of the I-beam. Each side of the roof would work structurally by itself with the inverter trusses, where as a standard truss would span the whole width/depth of the building and be it's own structure entity, instead of relyng on the the ridge beam and other half of the roof to complete the structure.

Am I in the correct frame of mind?

If going with an inverted truss on each side of the roof, what would be recommended for the ridge beam?

By the way, I'd like to keep the load rating for the I-beam and hoist between 2000 and 3000 pounds. That should be enough to hoist about any engine, frame, or small piece of equipment up to the loft.

Keep the input coming! I'm only an expert in ideas, and far from being an expert in anything else...

 

[scootermcrad]

I did mine like this, with a scissor truss, however mine is a 32 x 24 2 bay garage.

It's not 100% clear, but you should be able to get the idea. I get the point of hoisting things, but I don't feel like that truss design would hold a lot of weight. Mine is only an 8-12 pitch on the roof side, and a 6-12 on the inside, but that still gets me 5' higher than my floor.

I like the hoist idea though, maybe I'll put a small beam up there to make this work for my storage area.

x...

Thanks for the input! And great looking garage, by the way!

 

[scootermcrad]

Here's a super quick elevation. Maybe this will better explain the structure layout as well as what I'm trying to accomplish with the I-beam transfer. I-beam supported at either end with 6x6x0.25 wall welded square tube columns and assisted by the ridge beam. I would do welded flanges to the top of the I-Beam about every 32" to "hang it" off the ridge. This would allow the ridge beam and I-beam to work together.

Maybe not a good idea, though. Could many use a taller I-Beam and have it self supported, but 36 feet is a super long span to stretch without the aide of the ridge beam.

 

[scootermcrad]

Being that it's a high pitched roof, can I get away with simply using heavy beams instead of trusses?? Seems like the cost would be higher and more difficult to raise into place, though. Thoughts??

 

[wnstwolf]

We used what are called TJI laminated trusses in our roof structure for the timberframed section of our new house. While we have decorative King truses they are not structural the TJI's are really holding up the roof. A-frame with the clear space below 20' wide. As mentioned you will need your truss company to do this but we just showed the supplier our dimensions of the room below and he provided certified trusses like what your looking for. Not sure I would start lifting cars from it but then again..

 

[scootermcrad]

We used what are called TJI laminated trusses in our roof structure for the timberframed section of our new house. While we have decorative King truses they are not structural the TJI's are really holding up the roof. A-frame with the clear space below 20' wide. As mentioned you will need your truss company to do this but we just showed the supplier our dimensions of the room below and he provided certified trusses like what your looking for. Not sure I would start lifting cars from it but ten again..

Good info! I would love to see a couple pictures, if you don't mind.

Relatively speaking, was it quite a bit more than the average roof truss?

 

[kbs2244]

There is no need for using trusses.
If you want a double slope ceiling O K

But this is how to do it as a ridge beam construction (not ridge board)
In this style of roof the rafters are in tension so there is no need for joists.

You do need a post at each end of the ridge beam for support.
In your design I would put a post at the wall of the loft to reduce the span.
Though if you use a 36 foot beam you could get stuff in and out of the loft with the winch.

 

[Sunstealer73]

I did mine similar to Xander's post. 1/2 is attic trusses and 1/2 is scissor trusses. I have a 12/12 roof too. You can see some pics in this post:

http://www.garagejournal.com/forum/showpost.php?p=1724353&postcount=22

 

[scootermcrad]

There is no need for using trusses.
If you want a double slope ceiling O K

But this is how to do it as a ridge beam construction (not ridge board)
In this style of roof the rafters are in tension so there is no need for joists.

You do need a post at each end of the ridge beam for support.
In your design I would put a post at the wall of the loft to reduce the span.
Though if you use a 36 foot beam you could get stuff in and out of the loft with the winch.

Oh! Great! That's good info!

Yeah, I would really like the beam to go from end to end so i can trolley up into the loft. One issue I'm concerned with is the SIZE of that I-beam, as well as the ridge beam.

Sunstealer... My loft/mezzanine area will be framed similar to yours.

So, are the larger rafters going to be just as large in price? How are prices of something like that vs. a truss? Certainly seems like it would be the most simple solution. Are we just talking 2x12 rafters with an extra sturdy ridge beam?

 

[kbs2244]

Since this style of roof construction has fallen out of style it is hard for some to get their head around
it.
The “I” beam can act as the ridge beam. It most often does.
You just fasten a 2x on top to have something to nail the rafters to.
The 2x is not structural.

The rafters are in tension and have only a snow load as a load.
(With a 12/12 pitch, this will not be much.)

You will have to consider both the static load of the building and the live load on the hoist in sizing your beam.
I would visit your local steel yard.
The guy the local builders get their steel basement beams from.
They do this sort of calculation every day.

The great thing about this is not only a hoist trolley possibility but the fact that the ceiling is now the bottom side of the roof.
There is none of this low ceiling preventing a lift problem everybody seems to have.
You get a very big room space wise when you don’t have all that wasted space that a ridge board/joist style or even a scissors truss style roof gives you.
It is a true vaulted ceiling, not the “half vault” of a scissors truss.

 

[scootermcrad]

And here's where you guys will think I've got a screw loose...

I did a little thinking about the loft area of the garage and it's as-built usage as well as is potential future uses. I'm now thinking that maybe where the loft originally ended, I'll end the I-beam there and move the column to that location which reduces the overall span, which would reduce the overall web height of the beam and the weight and in-turn the cost as well. Would end up being more like a 24 foot long I-beam. So that I can still hoist things up to the loft, I'll do a partial cover over the middle bay area which would increase the square footage as well as a place to hoist to. Only doing a partial cover will also keep that open feeling to the garage/shop. AND! With a little bit of flare (and a little extra work) it can be architectually pleasing as well....

Now the down side to that plan is it wouldn't allow me to use the I-beam as the ridge beam.... Or COULD I?? Would be back to increasing the overall beam profile, but maybe it wouldn't be that big of deal. Hmmmm.

Here's the upper floor plan. Also notice the rear portion of the building. If I ever wanted to convert that loft space into another room I could. Probably wouldn't, though. I have too much junk to store. Haha!

 

[FastEddie2]

Good evening, I have a similar garage and had the exact same idea for modifying mine. The pictures are Awesome! Do you have dimensions / plans that I might be able to use?

Very Respectfully,
Eddie

 

[rburke65]

Shouldn’t be any guessing on trusses. Go to a big box store, local lumber yard, truss company and have them help you choose what you need.

 

[FastEddie2]

Shouldn’t be any guessing on trusses. Go to a big box store, local lumber yard, truss company and have them help you choose what you need.

Thank you! I tried Home Depot and they told me to contact an engineer. It really seems like a pretty simple job. I called an engineer and left a message, but never got any further.