How to add additional ceiling joists?

[gorms]

I've tried looking into this but can't seem to find an answer. I have found others asking the same question but yet no answer.

How do I add additional 2x6 ceiling joists that will rest on top of the top wall plate in a 18ft wide garage? I can't seem to think of a way to get them up there given that their lengths will be about 7" longer that the internal garage dimensions (3.5" bearing on each 2x4 top wall plate. There are a few ceiling joists there currently but I will be adding a drywall ceiling and cover the top with plywood for some storage so looking to add to every rafter spacing 16" on center. Is the trick to accept about half the bearing surface on each wall such that they can installed by biasing one direction in order to allow clearance for the other end?

 

[SH7mi]

Any pictures to get a visual ?

 

[rsanter]

I've tried looking into this but can't seem to find an answer. I have found others asking the same question but yet no answer.

How do I add additional 2x6 ceiling joists that will rest on top of the top wall plate in a 18ft wide garage? I can't seem to think of a way to get them up there given that their lengths will be about 7" longer that the internal garage dimensions (3.5" bearing on each 2x4 top wall plate. There are a few ceiling joists there currently but I will be adding a drywall ceiling and cover the top with plywood for some storage so looking to add to every rafter spacing 16" on center. Is the trick to accept about half the bearing surface on each wall such that they can installed by biasing one direction in order to allow clearance for the other end?

I think you are on the right track there.
You can actually do a little better than half but not much as you can insert them at a diagonal between the exsisting rafters

Bob

 

[Fishingfoolemjak]

Can you stand to lose 3.5” on one side? Build a false 2x4 wall on one side and then you would be fully on each side.

Could you not cut them in half, sister them to existing joists with nails and glue (and screws if possible)? I say nails and screws because nails have the shearing strength and screws have the pulling strength.

 

[BrendanBehan]

I gather you have some kind of existing scissor joist there, want to put up 2x6's and have them rest exactly between each joist on the top plates...and you can't push one end of 2x6x18'7" into the eave, lift the other to the opposite wall plate position.

Is that kind of what you are trying to do?

Uh, if you can't sister them to the existing joists you probably will need to overlap/sandwich shorter pieces and nail them together to make it one. Or put a beam down the middle and 2x6 to that.

 

[readhead]

My guess is that you have a few in place already to hold the walls together when it was built back in the middle of the last century. 2x6's 18' long are barley going to support the drywall. Don't even think about storing anything up there.

 

[Falcon67]

Put these up in a 16' wide, no real issue getting them in

As for weight, I had about 500 lbs of **** up there after rework - pipes, lumber, couple of fenders, misc stuff. No problems.

 

[Kaizen]

other option is to connect both existing joists and just run half the length to that with hangers.

 

[TractorJeff]

Last 18 foot wide building I was in had 2 x 12's nailed together in the center of the building! You know, one from each end?
Just Saying.........

 

[The Tool Tyrant]

I think you are on the right track there.
You can actually do a little better than half but not much as you can insert them at a diagonal between the exsisting rafters

Bob

^^Exactly. You don't need full bearing (think of a joist hanger which only allows 2" of bearing)
Cut the new joist 4" longer than your inside, wall to wall dimension, place one end on the wall, next to the existing joist, place the opposite end diagonally against the other existing joist, slide it onto the top plate until you have 2" of bearing and nail it in place...easy peezy.

 

[Evilunclegrimace]

Take a short scrap, make a template to match the roof angle and height of the end plumb cut. Get an accurate over all length measurement, mark and cut to match the template, slide one end on top of the wall and angle the opposite end to the other wall and flex the joist to allow it to set on the plate and stand it up.

 

[Ch3No2]

All correct ideas here....cut them short after you measure for a diagonal install with a roof pitch cut and let them rest on half the top plate. Done all the time when there's a second floor above and there's a rim joist running around the perimeter sitting on the outside edge of the first floor plate which allows for half bearing (2").

 

[theoldwizard1]

Years ago this what my Dad did (part of a long story). Cut the new joist about 2/3 the length of the width, in your case 12'. Overlap the 1/3 (6') in the center. Screw and glue.

Double check the width between the top plates (may require a cone-a-long to pull the top together) before toe nailing. I would also use some kind of hurricane strap.

 

[ssdave]

Short bearing, can be as low as 1 1/2", but 2" is preferred. Solid block it to the adjacent joists to keep it from rotating. The drywall ceiling will add additional bracing. It will all be good.

 

[matt_i]

You can calculate whether it will tilt in place. Think of a right triangle with the short leg = space between trusses (22-1/2 sometimes). Long leg being the ID between the walls, and the hypotenuse = the length of the timber (with bearing) that you intend to put up.

The idea of sistering with nail patterns and construction adhesive works.

Otherwise its peel off a piece of the roof deck when you reroof to install the timbers.

 

[firebirdparts]

You just lay it flat and up it goes. It needs to hang over 3-1/2" only to get the full length in there, and if it won't go, you can cut a little off. If you are dealing with 2 x 6 rafters, and they had a birdmouth cut, then you may have to dogear the corners too.

But it's too easy, really, to have to ask on a forum. They'll go.

 

[gorms]

Thanks for all the responses. I will likely cut them to have 2” bearing on each side and then tie them together with short cross braces. I plan to store totes and some long items (skis, extra 2x4s) up there so not much weight to support but I’ll be crawling up there occasionally to connect lights and maybe button up some wiring. For a 22x18 garage with the joists running across the 18” width, should I tie these to the rafters to support my weight?

 

[gorms]

But it's too easy, really, to have to ask on a forum.

I’m good enough at geometry to know it’s not quite that easy. Problem is there are joists present already that don’t allow me to angle them in XY to get them over the top plate. Bending is theoretically possible but even with eye hooks and a rachet cable between the far ends, 2x6’s won’t be easy. My options are to use shorter lengths and overlap them in the middle, or reduce the bearing surfaces until they will get up there. I like this last option better. Thanks!

 

[rzims]

This is a perfectly timed thread. I'm also in the planning stages on this. Current garage has cross bracing every other joist (32") and I'm trying to fill in the in-between with new 2x6's
Previous owner added a few where he made a storage area and joined them with overlapping boards and thru-bolts. Unfortunately those are starting to sag..

 

[The Tool Tyrant]

gorms, Here is option 29-B...Cut a 2x6 block to fit snugly between the existing C/J, place it on top of the wall, flush with the inside wall face and toe nail it into the existing joist. Do this on both walls, then cut your new 2x6 to fit between the walls, slide it up until the bottom is flush with the block, lastly install a 2x6 joist hanger at each side...DONE.

 

[Trey T]

OP: my 2-car garage had 2x10 joists spaced every 48"OC. They're about 22ft long (IIRC) and I did exactly what youre thinking about, "by biasing one direction in order to allow clearance for the other end". However, my project was slightly different, I converted all my joist to 4x10 with 48"OC.

 

[cdestuck]

You might not like this but on one side of the garage roof, remove some of the lower shingles. Cut open the sheeting and slide it in. Sounds a bit of a pain but it'll work.

 

[Falcon67]

As noted, I didn't have to do anything that drastic. Cut the joists full length, laid over the existing joists turned flat to the ground and moved one end until it dropped in place, then slid the other over to drop in. Turned up on edge, hammered into place. No cutting roof or splicing the lumber. Used the same to sister the two broken joists in that shed.