Ridge Cracked/splitting

kydd3

I just completed nailing all rafters (39 of them, 2x8s) to the ridge (2x12) for a garage I'm building, and I've now noticed several large cracks/splits all along the rear face of the ridge board. The cracks generally span several rafter bays (maybe 4-5 ft), and several run next to each other. In one place near the center (it is a 2 piece ridge (2 12 foot pieces)), the crack is all the way through. When you look at the front face of the ridge board, there are really no cracks at all and it is completely smooth.

Removing the ridge at this point would be a nightmare. It is not a structural ridge. My question is are there ways to fix the problem short of removing the ridgeboard? Such as plywood scabbing or placing a beam underneath it? Thanks. (I have pics, but because I'm a new member, I can not post them until, I've done 15 posts)

Pavola

Where are the collar ties? It wouldn't hurt to add short collar ties under the ridge board and/or post up from your collar ties to the ridge board. Clarify what you mean by 'not a structural ridge'.

neolitic

If you have continuous joist attached from seat cut to seat cut, the ridge board is just a means to join the rafters to each other.
While it wouldn't hurt anything to "gusset" it (1X collar ties directly beneath the ridge), the ridge is really just holding the spaces between the rafters.
It's not serving as a beam as such.
I don't think you've got to worry unless you think it's gonna disintegrate!

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kydd3

I haven't added the collar ties yet. Just finished nailing up the rafters. When I say "not a structural ridge" I mean its not carrying a load down the walls. I'm a little new to this so I may be misusing the term. The slope is 11:12 off the front and 3:12 off the back (gable roof), so collar ties right under the ridge would have to be angled quite a bit. Should they butt right up against the bottom of the ridge? What about the idea of also sandwiching it with 1/2 plywood? Thanks for the feedback.

Pavola

Like neo said, the cracks/splits aren't much to worry about if your collar ties are in. Usually the continous ceiling joists are all you need unless the span of your rafters exceed their specs. and/or your area requires a greater snow load rating. They may require a structural ridge or more collar ties.

neolitic

the seat cuts of the 11/12 and the 3/12 sit on plates that are in plane (level with each other)?
How long is each run?
And where are you?
Add your location to your signature and it saves lots of back and forth.
A roof in Idaho and one in Florida have very different issues.

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kydd3

I'm in East Hartland, CT. We get a lot of snow where I am (~1000 ft above sea level) I'm not sure I understand the question about the seat cuts being in the same plane. Basically its a cape style garage, 24' x 24'. The front rafters span (run) 12 ft, and have a rise of 11 feet. The rear is basically a full shed dormer. The rear rafters run down to a wall that is about 7'10. The front rafters are around 195" I believe (they are cut from 2x8x20s). The rear, I'm not sure (they are 2x8x14s).

kydd3

I think I see your point now. The collar ties I am installing will run from the top of the rear shed dormer wall and intersect with the front (11:12) rafters at that height, which is well above the front plate.

neolitic

I think that your ridge is becoming more "structural" as details emerge.
Was this drawn by an architect/engineer?
Did it call for a continuous ridge?
Would like to see the "cracks".
You can type in a link, just don't make it "hot"

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kydd3

here we go: i232.photobucket.com/albums/ee190/kydd3/ridgeboardpics004.jpg
i232.photobucket.com/albums/ee190/kydd3/ridgeboardpics003.jpg i232.photobucket.com/albums/ee190/kydd3/ridgeboardpics002.jpg i232.photobucket.com/albums/ee190/kydd3/ridgeboardpics001.jpg

A W Smith

You mean like a salt box roof?

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A W Smith

I would at the very least scab a piece of plywood on both sides of the ridge at that splice

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neolitic

That's one ugly piece of lumber.
Is it SYP?
Look like that before you started?
What ever, those clips aren't doing much good now.
Think I'd back nail all of the 3/12's with 2 - 12d or 16d's, and either set another 2X12 under, or run ½' plywood rips in each space to hold it together.
Man, if you set that thing up there looking like that....
Well, we reap what we sow
3/12 with snow is a lot like a flat roof load-wise.
Your joist connections are now very important.
Maybe ought to think about sandwiching rafters at 1/3 points.
Good luck.

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wink

that ridge looked a little green is it pressure treated? that might have something to do with it i take that back it didn't look to green in the next pic,

wink

i take that back it didnt look to green in the next pics.

Tom M

A ridge beam less than 3:12 is considered a structural beam and need to be designed like one. I think your on the cusp. Collar ties are a must. Who signed off on this design?

BuiltByMAC

How about taking some Simpson MSTA straps and wrapping them around the ridge beam every 4'? Your lumber would never pull apart at the seams after that.

Mac

oldfrt

kydd3

How you doing neighbor? I'm about 10 miles away from ya.Small world .

Was that ridge fully supported as you nailed on the rafters?Say down to the ground or cross beam?If not that may have caused the cracks to appear.What size joists are you using and are they running in the same direction as the rafters?
As neolitic says,those joists connections are very important.That roof will literally try to spread those walls out,especially with a snow load.(we seem to be getting a little of that today)
Do you have pics of the ceiling joists details?

wallmaxx

Ditto MAC - or cut roll strapping into "U" shapes and nail in each bay.

kydd3

Hey Oldft, yes there's some snow up here today. Where are you, barkhamstead? The ceiling joists/collar beams are 2x6. The rafters run in the same direction as the floor joists. At this point, I was thinking I would scab plywood on both sides, nail and glued, and then place 2x6 collar ties/gussets right up under and against the ridge. WHat'd do you think? Would straps be better than plywood? If that doesn't pass, I suppose I could always place an LVL beam underneath the ridge and carry that down through the sidewalls. I can't see myself replacing the ridge board. Way too many nails in that thing. It was supported at both ends and in the middle when I nailed it, but the cracks definitely appeared or at least became noticeable after I put it up. Thanks to everyone for the input.