Things to consider when designing a garage

[sdo]

Hi, I'm new here. I am hoping to build a garage approx. 1000 sq ft, with a "bonus room" type attic. The main constraint I have is a max height of 25' due to zoning.

Due to the height restriction, I assume that will govern how wide the garage can be at a given roof pitch. At this point I'm not sure what that width will be and still allow for an 8' ceiling at the center of the attic.

The width of the building will then in turn help me to decide if I have enough room for 2 overhead doors on a gable end, or if I need to start thinking about putting them on the side of the building. Is there any reason not to put overhead doors on the side? One I can think of is rain run-off, unless gutters are installed, you have to pass through a waterfall to get in and out of the garage in the rain. I realize gutters are a simple fix for that. But are there any other issues that may be more important to consider?

Also there is the question of built on a foundation vs floating slab. Slab would be cheaper, but in the freeze and thaw state of MN, maybe not a good thing.

Another is access to the room above, whether from inside or outside the garage.

If anyone has any pointers or comments, doesn't need to be terribly specific, just some basic things to

I am just drawing on the experience here to hopefully prevent me from saying... I wish I knew this before I decided to do it.. etc.

The ideal size would be something around 30 x 36.

I'd love to see photos of garages with attic trusses.

Thanks

 

[Kaizen]

I'm doing a 30x36 now. My code said if I wanted a room above I had to do a foundation and footer. I just went basic. Plans have three garage doors on the 36 side. My walls are total twelve feet high and I got 8/12 trusses which are ten feet four inches high. If you do a room and use I joists for the floor and conventional rafters it would be about eight high for most of it. You didn't say how high garage ceiling you wanted

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[dshop]

attic stairs INSIDE for sure. You're not gonna want to shovel off 15 stair steps when it is 20* and snowing anytime you want to go upstairs. Safety first on this one.

 

[73RR]

You can have 2- 12' ohd in a 30' wall. (2 + 12 + 2 + 12 + 2) It is a little tight and your permitting agency will want to see shear panels in the three 2' sections but it is doable.
If the 30' is the gable end you can use 12' walls and a 7/12 pitch for about 9' at the ridge. ...and you are still 3' short of the 25' max.
Your truss maker can lay it out with various dimensions so just tell him what plate height you want to use and let him put the ridge at 24'-9" and see how much storage space you can get.
I just talked with a truss plant about some storage trusses and said that I wanted a min of 12'-1" width so that I could lay full sheets of ply down and he said he would see how much more he could give me...lots-o-flexibility these days with the computer generated loading designs.

A frost protected shallow foundation will support 2-stories so it is a good choice especially if you want to add floor heat.

 

[Keith_MN]

I would put the stairs inside also. They take up space, but not having to shovel them would make up for it.

Another consideration is the direction the garage doors face. Water dripping off the roof on the North side can create lots of ice. South side would not be nearly as bad.

 

[Ray916MN]

Speaking from experience in Minnesota, if you want to put a garage door on the non-gable side of a building you need to think carefully about the direction of exposure and potential for snow to build up on the roof and avalanche off. Depending on the pitch and the exposure it isn't uncommon to have snow sliding down the roof rip off your gutters and bury the access to your garage. You will also want to make sure your gutters don't freeze. Melting snow refreezing over and over in the gutter will clog the gutter if it freezes. Eventually if you get water dripping off the gutter onto the apron, you'll end up with an ice covered apron. This is particularly a problem if your garage door faces north.

 

[rusty1]

,...my building has the doors on the eave side facing south, no gutters, never had a problem with rain or snow so bad that it was a big concern, not much snow stays on my roof.

 

[spudley]

Speaking from experience in Minnesota, if you want to put a garage door on the non-gable side of a building you need to think carefully about the direction of exposure and potential for snow to build up on the roof and avalanche off. Depending on the pitch and the exposure it isn't uncommon to have snow sliding down the roof rip off your gutters and bury the access to your garage. You will also want to make sure your gutters don't freeze. Melting snow refreezing over and over in the gutter will clog the gutter if it freezes. Eventually if you get water dripping off the gutter onto the apron, you'll end up with an ice covered apron. This is particularly a problem if your garage door faces north.

I'm planning a 24x38, 12/12 pitch with doors on the "non-gable" south side and I've also been concerned with snow sliding. My thought was a couple of gable dormers above the doors? Think that'll work?

 

[terabitdan]

I went with a gambrel style to maximize the attic space. 21' truss span resulted in 13' 3" of 6' 8" open space, 32' long while staying within zoning height restrictions.

A side entry design with 10' walls, 30' wide would place you right at 25' overall height. Leaving the first bay without an attic for the lift should leave the attic at 22x24 with 6' 8" of clearance.

A typical gambrel truss height is 1/2 the span, so 28' width allows for 11' walls and so on.

For comparison, the 8/12 roof example above there would be about 15' (or half the building width) with 4' or more wall height and about 11.5' of 6' 8" headroom.

We had to have a full foundation for anything bigger than 400 sq ft, so adding attic space didn't increase my foundation costs, and doesn't count against the maximum sq ft size.


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[Stuart in MN]

I'm in Minneapolis. I have a 24 x 40 garage, with 10/12 pitch attic trusses, sitting on a slab. The attic space isn't finished, it's just for storage. I use a folding attic stair to get up there, but it's not very sturdy. There's a double and a single door on the eave side. I've had zero issues with snow sliding off into the driveway, but the rain does pour down off there in warmer weather (I don't have gutters). However, that's really not a big deal. It's about 19 feet high to the peak.

I recently posted a couple photos in this discussion: http://www.garagejournal.com/forum/showthread.php?p=6264548#post6264548

 

[Ray916MN]

I'm planning a 24x38, 12/12 pitch with doors on the "non-gable" south side and I've also been concerned with snow sliding. My thought was a couple of gable dormers above the doors? Think that'll work?

12/12 should shed snow before it can build up to be an avalanche. Add dormers and you should be plenty safe. Guttering would be good. Rain water will build up quite a head of steam coming down a 12/12 pitch roof.

 

[matt_i]

The bonus room above is challenged with hot and cold, not sure how you plan to use this...just storage or were you planning to watch football out there?

As was mentioned, I would research and build a frost protected shallow foundation if you don't want to build a full traditional foundation.

I have a 12' wide attic in my shop but its only 6:12 so I cannot walk upright in there. The other shop which was existing has a 10:12 I believe and it is much more walkable.

 

[tomroblee]

Trusses can be all sizes and shapes. If I was going to maximize second floor area with a modest height, I would use something like what was shown in a several year old post.



I also vote for stairs inside unless you enclose the "outdoor" stairway. As others have mentioned, a lot depends on how you intend to use the second floor. Fold down attic stairs might be OK for light storage, but less appealing for a living area. . If you are going to use the area for a living area, you may have all sorts of other issues like having a fire barrier between the garage and living area, emergency egress options, etc.

Basic attic trusses are great for light storage. Just make sure that whatever you use is designed for how you plan to use it. The most common (cheapest) attic trusses may give you a pretty bouncy floor. The size of the truss members may limit the amount of insulation you can install

 

[MushCreek]

If you're willing to go gambrel-style, you can have a large, usable loft. My barn is 12' 4" clearance downstairs, strong floor for the loft, and 8'+ in the loft. I am at about 27' high for a 28' wide barn, though. To get ideas/inspiration, check out barnplans.com. I used their plans, and the building method is unique.

 

[sdo]

Thanks for the information, all of the input is very helpful

 

[Laredo]

Hi, I'm new here. I am hoping to build a garage approx. 1000 sq ft, with a "bonus room" type attic. The main constraint I have is a max height of 25' due to zoning....

I would also recommend to check local zoning specifics for your "bonus room" plans. I had the same type of 2nd level space planned at my last house, city said "no" to any space above garage that could be used for or converted to in any way a "possible future occupancy." I was limited to lower ceiling height, rafters, etc.

 

[Buck]

I don't know how the planning for climate and snow affects it but mine is a 28 deep 32 wide. I have a build thread that shows how I framed it. I have 2 bays. One has a room over it that is about 13'x22' best I remember. The other bay has 15' ceilings for my lift.
Putting in a landing and changing directions on the stairs helped a lot so they aren't too steep.

 

[ddawg16]

I was limited to a max of 15'.....but the upper floor is all usable...you can walk down the center without ducking.....

Maybe consider a spiral stair case? Takes up a lot less room and it's actually pretty easy to get stuff up.



I have a ridge beam supporting my roof.