Adding Ceiling Joists In A Old Garage

[dwall174]

I have an old 2-1/2 car garage (20' Wide X 24' Long) I insulated the 2" X 4" framed walls with some R-13 insulation & finished the walls with 1/2" OSB several years ago, And now I want to add a ceiling to finish it off & help insulate it a little better.

The inside wall height is only about 90" & I have a 7' X 16' overhead garage door, So the actual garage door track is slightly above the side wall height. My original plan was to just install some 16' long 2" X 6" ceiling joists placed about 2 feet in from the side wall something like this.




This would give me the room needed for the overhead garage door & it would give me about an 8' ceiling height, But I'm not sure if attaching the ceiling joists to the 2" X 8" roof joists would create a problem with the roof sagging down the road?

Would adding some additional 2" X 4" supports from the ceiling joists to the roof joists help? Or hurt?

Doug

 

[Half-fast eddie]

You would be adding weight to roof rafters … not a good idea. Almost zero chance the rafters are designed to support additional weight.

What is the goal? Light attic storage?

 

[dwall174]

What is the goal? Light attic storage?

The main goal would be to help insulate it a little better!
There really wouldn't be too much room for storage other than for items like rakes & shovels etc.

Doug

 

[dwall174]

You would be adding weight to roof rafters … not a good idea. Almost zero chance the rafters are designed to support additional weight.

I've been there done that, Not that I would recommend it.

I have an old 1-ton chain fall attached to the main center beam & I have used it to move heavy items before.

Here's a couple of pics of me unloading a all cast-iron bandsaw with it, Probably weighs around 600lbs.



I'm sure the rafters were never meant to handle a load like that!

Doug

 

[wrenchguy]

You have 2x8 rafters now without any horizontal ceiling joist? What are your rafter centers?

 

[quickfarms]

What type of roof is up there and how many layers are up there?

 

[dwall174]

You have 2x8 rafters now without any horizontal ceiling joist?

Well maybe I'm not calling them by their correct name, But the 4 corner roof rafters/joists & the main center rafter are 2" X 8" The other side roof rafters are 2" X 6"

What are your rafter centers?

The rafter & side walls are all 24" centers!
As for any horizontal ceiling joists, All there is a couple long 2" X 4" going from side to side & 1 going from front to back!



Doug

 

[dwall174]

What type of roof is up there and how many layers are up there?

It's a Hip Roof style with asphalt shingles with two layers!


Doug

 

[PoorUB]

2x6 and 2x8 framing? I don't have an issue doing what you propose, but I would take it one step farther and build trusses out of the center three.
With all the weight of the shingles you may want to support the peak, and jack it up an inch or so, then remove all that mess of framing in the center of the garage and like I said, frame in the center three rafters into trusses. It would even be better to double up all the framing on the outer two, then frame your ceiling back to them. Use 1/2" plywood for all the connector plates with a good construction adhesive.
Keep in mind you need to support the peak if you cut out the long collar ties that go across at the 90" height. If you don't you will have a real mess on your hands!

If you do it, carefully measure everything to make sure the walls are straight and plumb. you might want to pull them in slightly as things will settle and push the walls back out.

 

[Half-fast eddie]

The main goal would be to help insulate it a little better!

Then why not just attach batt insulation to the rafters?

 

[wrenchguy]

I'd rebuild the roof or temp up the roof framing and remove the joist and replace on 12" centers. Its CRITICAL that these are 100% fastened to the top plate and rafters that they lay to. You should done ceiling first, now you don't have access the bottom side of top wall plates.

 

[dwall174]

Then why not just attach batt insulation to the rafters?

I've thought about that, But that's a fairly big area where heat is wasted.
I could always put a ceiling fan up near the peak & circulate it back down.

Doug

 

[dwall174]

I'd rebuild the roof or temp up the roof framing and remove the joist and replace on 12" centers.

Yeah that sounds like way too much work for a garage that was built back in the 60's

Its CRITICAL that these are 100% fastened to the top plate and rafters that they lay to.

That's kind of what I was thinking of also!
Something like shown in this picture is kind of what I was thinking about to help transfer the load to the sill/top plate?

You should done ceiling first, now you don't have access the bottom side of top wall plates.

Where's the fun in that! That would have been too easy.

Doug

 

[wrenchguy]

My paragraph about if you take off what you have and replacing with new didn't show up. This way you could build knees to a desired ceiling height. good luck with your project.

 

[Zeke]

This is very doable but some study needs to go into this. I used to build but I got into the door and window business in '85 and haven't built much since. IIRC, collar ties can be anywhere in the lower 3rd of the rafter. If you run them all in one direction you lose the bracing that is provided now with one or the other of the collar ties running perpendicular to the others.

Last time I saw this done, new ties were run for the basis of a raised ceiling as you want to do. However, attention was paid to the perpendicular tie by running a couple more just above the 2x 6's. Lots of hardware was used. Sistering the rafters like you show looks good.

Another thing you can do is hang a suspended ceiling at 96" and lay insulation on that. With some drop in light fixtures that could look very nice and add next to nothing for weight. But you still have to deal with the low hanging ties. Just less lumbar.

It shouldn't take too much thinking to work this out if you can find a competent framer that can give you some guidance on hardware and attachments. There are all kinds of retrofit pieces available.

BTW, the terminology is hip rafter for the rafters to the 4 corners and any rafter not going all the way to a ridge is a jack rafter. The above advice about making some center ties/joists into a truss is a good one. Go the short way on these. I'd work in there after it was done, IDK about the rest here.

 

[Half-fast eddie]

Another thing you can do is hang a suspended ceiling at 96" and lay insulation on that. With some drop in light fixtures that could look very nice and add next to nothing for weight.

Especially in Calif, the light fixtures have to be independently supported off hanger wires.

 

[PoorUB]

Especially in Calif, the light fixtures have to be independently supported off hanger wires.

Code everywhere as far as I know. You are not supposed to hang anything on the ceiling grid, other than ceiling.

 

[billconner]

When you raise the rafter tied or ceiling joists (always in bottom third of rafter to tie walls together vs. collar ties aka collar beams which are in the top third and to keep rafters together from wind uplift) you decrease the allowable so pan of the rafter. So 2x6 rafters that might be good for a 12' span - top plate to ridge horizontally - with rafter ties on the top plate, are only good for 8' span when rafter ties are raised to third point.