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Will 06-20-2006 07:57 AM

Cieling In Garage Addition
I'm the guy doing the garage addition - the one where she wants a two room suite level with the house built in the garage ( see previous post, addition in garage). what do you think I should use for the cieling. she seems to want the studs to go all the way up, like 15 feet to the ceiling of the garage. However I'm sure she doesn't want the ceiling of the rooms to be that high, she probably just wants a regular ceiliing. so how would the ceiling joists work - just run 2x4's across the ceiling from the studs that are going up? I planned to have the studs 16 on center so the ceiling joists then would be that too. But this would leave like a large enclosed area ( enclosed by sheet rock) going all the way up to the high garage ceiling, above the room ceiling. Is this desireable? Maybe I should have the ceiling just go up 8 feet and stop there - i.e. the ceiling of the whole structure just only go up that high.
As far as the ceiling joists themselves, are 2x4s spanning 11 1/2 feet ok, placed 16 on center? or you think I should use larger dimensional lumber - 2 x 6 or 8? Ya see, if I have the studs running way up to the ceiling, I wont have any top plates to rest the joists on. I thought I could basically hang them (joist hangers) instead, or just screw the in toenailed. Doest really seem sturdy enough for a ceiling though. If I only make the ceiling go up 8 feet though, I could do it the usual way, run joists across the top plates. What do you think I should do?


inspectorD 06-20-2006 10:27 AM

Your OK
I would do the walls at 8' and put joists on top of the walls to make a storage area above the room.
You would have to sheetrock all the way to the top of the joists.Run a rim joist to hold the floor joists together so they dont flop over.
Use 2x8's 16 OC they should be enough for attic storage. Just tell her no engines or weight sets should be stored.:rolleyes:
Then use some 3/4 inch plywood to hold everything together at the floor.

Good luck, keep us posted.

glennjanie 06-20-2006 10:28 AM

Hello Will:
If you cut the walls down to a top plate I would use a 2x6 joist at least. When there is an open space like that people want to store things on it; then the question is "at what point will the load become too much"? The ceiling would need insulation if the short walls are used and you might sell the owner on some 1/2" plywood up there for a storage floor, and 2x8 joists to ease your mind on the load rating. As InspectorD always says, "check with the local code officals first".
If you run the walls all the way up you could suspend a 2'x4' tile ceiling with some ventilation to ease the pressure diffrential and you could lay 6" batts of insulation directly on each tile. In this case the trusses in the current ceiling would bear the load just fine.

glennjanie 06-20-2006 10:31 AM

Oops! Sorry InspectorD. I almost ran right over you. Will, he has some real good points there too.

inspectorD 06-20-2006 09:32 PM

I thought I could basically hang them (joist hangers) instead, or just screw the in toe-nailed.

Screws don't work well in toe-nailing or structural applications.
They do not have the shear strength a nail has due to the fact they are hardened steel.
If you were to put a screw and a nail in a wall next to each other, and leave them sticking out 1" , then hit them in a downswing motion with a hammer. The screw will snap and the nail will bend.

Only certain screws identified for structural use are permitted in some applications.

No sheetrock screws of any length or decking screws are allowed, contrary to some beliefs.

You should never see screws in a joist hanger.

Go to for a free video training kit on how to install hangers of all types.

Unless you are under the collapsed floor.:D

Square Eye 06-20-2006 11:19 PM

You'll lose your firewall if you have a loft open to the garage. I am a terribly picky person and I'll go to great lengths to make my jobs the best job for the money. That said, I'd lay all of my studs side by side. Set my saw 1 1/2" deep, and cut the sides of my studs to accept the joists. Your support issues would be solved. Especially if you used 2x6 studs. Then you can have your 97" from the floor to ceiling and still have a legal firewall.

asbestos 06-23-2006 09:52 AM

Square Eye makes a point about firewall. Codes vary. Since this is no longer going to be used as a garage (?) then the firecodes may be differnt. I know that here our code guy (actualy a code woman) is allways happy to talk with HO's about codes.
BTW and FWIW I am a firefighter here and we had a fire a few years back there was a fire in a converted garage made of concrete block. I showed up and the 'garage' was engulfed. the only extension into the house was a tiny spot in the kitchen.

Will 06-23-2006 12:07 PM

hey thanks for cool replies!
I'm wondering why I cant just build the walls to 8 feet or whatever and then pot joists and plank it over with plywood like you're saying, then run studs up from this on, say, 3 sides, one of which would be the house side. It would be open in front so she could use it for storage and it would still be a firewall because it would be enclosed on the house side, right?
Square Eye, when you say cut your joists on the sides I assume you mean make actual big eyelets through the studs into which the joists could fit and sit there. Like holes through the studs, right?
Also iw as wondering, Glennjanie, by tiles you mean a drop ceiling, right?

Square Eye 06-23-2006 04:45 PM

Your assumptions are correct, I think.

By cutting the sides of the studs, I mean cut a square corner notch out of the narrow side to accept the 2x. Like this [

Drop ceiling=suspended 2x4 tile ceiling.

Now, the space above your garage. If you are filling the entire space with the room addition, then forget the firewall. If there is still access to the garage space through an overhead door, then that area needs to have a firewall. The space between the ceiling and the rafters can be accessed from inside the addition, but a loft will negate the firewall by having a plywood floor. Plywood burns as good as anything and will transfer the heat and fire right through the framing and when the ceiling collapses, into the house.

We can't see what you have so, it's hard to guess what would be right.

Will 06-24-2006 09:02 AM

As it happens I just talked to her and the ceiling is only 12 feet from the basement floor, 9 feet from the house floor level. the ceiling of the garage I mean. so basically the question of space on top is moot, I thouight the garage ceiling was a lot higher. But the garage ceiling is the same height as, ie level with, the the house ceiling which makes sense. So basically the whole space is gonna be enclosed. when you say: "forget the firewall" what do you mean. as in I dont NEED a firewall or I cant build a firewall or what?
So now I guess the idea of notched studs so I can have a celing comes back into play. But then again, do you think the studs really need to be connected to the existing garage ceiling? what If I just still did it the other way, had complete walls with top plates, and then joists on top (ceiling joists) and the joists would either contact the ceiling or be like an inch from it. so the ceiling in the rooms would be like 8 inches below the house level, but the whole thing would be enclosed and there wouldnt be a need to hassle with notches and things.
also one more thing. I was talking to my half brother whos a carpeneter and he said he thought those 2x4 walls one of you (inspector I think) recommended on which the floor joists would rest wouldnt be quite strong enough. He recommended the studs being more like 2x6 down there on the bottom. any thoughts on this?
Also do you think only the sole plate needs to be PT or the whole wall (the whole wall under the floor)?
I guess the general question is: is there any ADVANTAGE to having the wall connected to the garage ceiling? or could it just be enclosed ( maybe even qith 2x4 joists on the top so it would be even closer to the existing ceiling.

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