Rafter repair

[TOE]

My garage has a rafter that is cracked. (see attatched picture)

There is also another rafter that was crudely spliced together, they were cut at around 30 degrees and nailed at the join.

They are 2x4s and are 16' across. The garage was probably built in the 50's (just a guess, the house was built in 1922).

I am planning to repair / strengthen them as I plan to eventually hang two 4' fluorescent light fixtures in the garage (they were there when I bought the house).

I also plan to mount a pull up bar to the rafters as my garage is also my gym (I weigh ~150lbs). So I want to make sure the rafters will be able to support the lights and me.

Can I safely do this by sistering them with a full length 2x4. What do you guys recommend?

 

[Bubbles]

plywood in between the 2/4 will help

 

[rodnok1]

Wow a 2x4 spanning 16'...I'm surprised more haven't busted. If there isn't too many boards nailed across top of rafters, I would take them off and sister on a 2x8. As a minimum I would sister on a 2x on both sides, since old lumber is actaully 2x4 you could cut down a 2x6 to get maximum size.

 

[dreamingmuscle]

plywood in between the 2/4 will help

I agree with the plywood if your going to support anything other then the roof with them. Rip 1/2" ply wood to size. Put it next to the cracked rafter on both side's then put 2x4 on either side of that.

If you not going to support or hang anything with them. Then just jack them streight and put 3/4" plywood on both sides atleast 4 foot past both sides of the crack or across the whole length would be better

Putting ply wood on all the rest wouldn't be a bad idea either if one cracked the rest are not far behind.

rodnok1 isn't giving bad advice either. If you can stand the height loss you could let the larger lumber hang down below the old rafters then support them with a 2x4 across the wall studs

Glen
________
starcraft replays

 

[kbs2244]

The plywood is a good patch idea.
But the best thing would be full width 2x6s sistered, with a common bottom edge. It will be OK to angle the ends to clear the roof if needed since it is the bottom of the joist that is under strain.
Do jack up any sagging ones as you do this. And don't be surprised of you hear the walls creak and groan. They are not stright anymore and as you jack upthe joists you will be pushing them back into their orginal position. Same with the rafters.
For your pull up bar, put the top support crosswise across 3 or 4 of the new 2x6 joists and your 300 lb neighbor can join you.
The lights don't weigh enough to worry about.

 

[TOE]

Thanks everyone for the replies so far.

One other question: Nails, lag screw or lag bolt? How far apart?

I was planning on gluing first then using a second form of fixation.

 

[walleyed]

The 2x4's are there to stop the walls from bowing out only. They do not actually support the roof from the look in the picture. I would just sister a 2x4 or maybe a 2x6 to them if you use the area above for storage. Use the 2x6 on those that would support your bar or any extra weight in the future. You can use nails or lags but I would probably use deck screws for ease of installation. Some glue wouldn't hurt either

Wally

 

[kbs2244]

walleyed has it right. Just in this case the walls came toward each other instead of spreading apart. Instead of being in tension they were in copression, and could not take the strain. Thus the bending and breaking.
When you jack them back up, you will be spreading the walls back apart.
I like to use drywall screws. No impacts to knock things around.
Use lots of glue and C clamps to get things lined up.
If you go with the plywood patchs, glue and lots of screws since the screws will be under stress. Every 8 to 10 inchs.
If you go with new full width 2x6s, then you are putting in new structal parts. The fastening at the ends will be the inportant point. Across the span all you want to do is keep them from tipping. So a screw every 15 to 20 inchs should be OK.