Cut out ceiling joists?

[3Series]

I know there's probably been plenty of discussion around this and I've searched the site, however I'm still confused about a consesus if there ever was one. I also know I should get an engineer stamp of approval but I wanted to know if anyone has anything else to add.

Bascially, I want to install a lift in my garage for car storage. I have, I think, a stick built Hip Roof. The garage (detached) is around 21X21 with joists that run the width of the garage. From what I know, these joists keep the walls from bowing out.

Does anyone have a similar structure where they cut a "hole" or so in the joists to get more ceiling height?

I've attached a drawing to illustrate what I want to do. I'll probably have to back my car in so the passenger area can go through the hole.

 

[willymakeit]

Double or triple the joist on either side of the opening.
You are doing the same thing as a stair or skylight opening. Go to one of the box stores and get a book on wood framing. Thats assuming yours is stick built. If it is built with trusses, consult a engineer or the truss manufactuer.

 

[maxspeed96ct]

My old thread might have some good info for you. http://garagejournal.com/forum/showthread.php?t=155946

 

[3Series]

I saw that thread. My garage roof doesn't have any vertical posts going from the joists to the roof. Well if it does, there's nothing in the middle of the garage or where I want to cut a hole.

 

[hthighway]

Here is some further reading on the subject: http://www.showroom411.com/AskRick/Question/Details-raising-garage-height-follow/70

 

[SGKent]

just keep in mind that if you ever sell or refinance it, permits and engineering may be needed - at a higher expense than now. Also if someone gets hurt by it or ir causes damage to the structure, the insurance company may refuse to insure the event due it not being permitted and engineered.

 

[Devildogs]

I'm no engineer but i looked in to doing this at my previous home. This is my understanding of what is involved. I look at the entire triangle that forms the triangular outline of the roof and ceiling as a large truss. When you delete the lower horizontal brace that holds the existing ceiling, this triangular truss will want to open at the bottom and transfer load to the top of the walls. To keep this from happening you strengthen the affected roof joist (the sides of the triangle)by doubling them up, and then you brace them horizontally at the new ceiling height. The higher you go with the horizontal brace the more load is carried by the diagonal legs of the truss so raise them only as high as you need to go. Again you double-up the joists that are directly against the roof sheathing to help them carry the additional loads when you move the existing brace up to the new ceiling height. This is what is done when you cut a hole for a dormer for example. You will also need to brace between the doubled joists to keep them straight up and down. But you’re going to get a PE stamp on a drawing to pull a permit so you’re going to have a drawing that will show all the bracing detail.

 

[Falcon67]

Double or triple the joist on either side of the opening.
You are doing the same thing as a stair or skylight opening. Go to one of the box stores and get a book on wood framing. Thats assuming yours is stick built. If it is built with trusses, consult a engineer or the truss manufactuer.

Same as I would do - frame it out like a big attic stair opening. Note that your headers on opening will have to carry the ceiling/dead loads on those joists out to the uncut ones on the edge of the opening, so doubling the ones on the edge and using substantial or double headers would be a good idea. Your sketch puts it close to a corner, so you are not going to have much of a problem with the walls IMHO.

 

[ydna]

You need to invite someone with experience over to your place to take a look at the project. And by that I mean a home builder / contractor who has an engineer he can work with.

 

[djjsr]

Don't rely on advice from someone who sounds like they know what they're talking about, including forum members here.

Get someone who is qualified. A structural failure can kill you.

 

[Dave Nelson]

You need to invite someone with experience over to your place to take a look at the project. And by that I mean a home builder / contractor who has an engineer he can work with.

^^^^ Good advice.

 

[vette66bob]

I have a 24 X 48 block wall garage with 2X6 joist in the front half and 2X8’s in the back half All the roof rafters are 2X6’s. The inside ceiling height was 9'. I consulted with an architect and created an 18' X 18'opening with a 12' ceiling height in the front half, to allow for a lift, I added collar beams on each roof rafters, constructed a joist system (using new 2x8, s) tying in the old ceiling joists and the new raised ceiling joists tying each to the rafters using a knee wall and cross bracing. Very solid and strong. It has been 2years and everything is holding up well.
It was hard of work but well worth the effort, the best part is there are no exterior signs of the modifications.