Modifying Garage for New Lift

[PorscheSki89]

In order to feed my habit (89 Porsche 911) I would like to install a lift for maintenance/repair work and second car storage. I have a 2 car garage with engineered truss roof, 9ft ceilings. My idea is to convert one bay to ridge beam/rafter roof and then remove the parts of the existing trusses on that bay (the right bay) to leave a vaulted ceiling about 16 ft high at the peak. Attached is a more specific layout I put together. The big question i have is whether or not I need to put a post/pole under the long joist going down to the garage floor or whether the joist itself would be enough given the low weight of the roof. Thoughts? Ideas? Comments? BTW, I live in Georgia so snow weight is not an issue. Thanks for any feedback.

Kevin

 

[JohnK007]

I'm no structural engineer but I would think that at the least you may have to either double that center truss or provide some sort of center support. The bottom chord of that extisting center truss alone may not be able to handle the additional forces on it. Truss systems are designed to transfer the vertical loads to the end wall, whereas rafter and ridge construction tends to push out laterally. My guess is that using collar ties on the conventional rafters woud help check these lateral forces while still giving you clearance for the lift. It's only an 11 1/2 foot span but I'd still have it checked out by an architech or engineer. Your building dept would probably want it signed off on by one anyhow.

It's an interesting idea you have there Kevin. Please keep us up to date on what they say.

 

[1931S/X]

ive been thinking of that, im looking at building a garrage if i move into a house im looking at, i was thinking if i went with the roof truss, i could down the open up one bay and do some reinforcing to carry the newly distributed load.

 

[Matti]

I'm not sure about the ridge beam design as you may need a steep slope with this design. I would consider a scissor truss which should give you enough room with 9 foot walls again depending on your slope restrictions. If I have interpreted your drawing correctly the roof slope must match the other half of the garage which will be your limitation. From what I have read about the scissor truss the interior slope is half of the exterior slope so you would need at least a 4/12 slope inside and an 8/12 outside. The other options is a raised tie truss design. I haven't found any design guidelines on this but it looks to be a useful design providing the tie can be moved up far enough to gain the desired height. In general. you may only have to modify enough trusses to get the roof height where the car will go ie 6 feet = 3 to 5 trusses depending on spacing. I have heard of guys cutting their trusses and boxing them in to gain another foot or so. I'm not sure about this idea!

ps I just bought a '95 Carrera and have plans for a new garage and lift too.

 

[Ironcrow]

Two of three beam ends are landing over window headers. Are the headers strong enough to support the concentrated load?