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plantrookie

Garage roof repair

plantrookie
9 years ago

Hi everyone.
I have a multipart question pertaining to my garage roof repair/remodel.

First, here's what I have:
Block wall garage, 16' x 28', trussed roof with gables, 24 " O.C., about 4:12 pitch.

Due to severe weather damage, I am ripping off the roof down to the trusses. The previous owner seemed to abhor anything resembling craftsmanship and once again I have to make it right (or at least righter).

For starters, the old sheathing is only 3/8 ply. It has failed in sections and now my garage floor gets very wet where I don't have the buckets (yes I saw this coming). However, in replacing the sheathing, I'm told that many folks around here go with 7/16 OSB. It's the cheapest option, but I'm not sold on it's longevity. I was thinking 5/8 TG OSB or even 1/2" ply? Your thoughts?

Next, get this, the eave overhang on my neighbours side is actually 6" shorter (and thus higher) than the other side. Why would anyone do this?? It's like growing out one sideburn. And to disguise it, they actually extended the rake fascia past the (really wavy) eave fascia on that side. It just kind of hangs out there to rot...it's the weirdest thing.
So, I plan on sistering the rafters to match the overhang on the other side. However, after I do, should I use a 2x sub fascia before my 1x6 fascia that I will wrap in aluminum to match the house? I imagine a 2x4 or 2x6 sub fascia might prevent any warping of the fascia...but is it really needed?

I also have to rebuild the rake overhangs. I can't believe they didn't sag or even fall off the way they are now. I am looking at a few options, and I understand some of the pros/cons of each, but I can't seem to find a consensus on the subject. Do I...

a) build ladders on the ground and screw/nail these through the gable sheathing to the gable rafter?
b) toenail/through-nail blocks to/from the gable rafter and then attach a fly rafter?
c) notch the gable truss and run flat 2x4 outlookers from the 1st common to a 2x4 fly rafter? Do I still need to put blocks back to the sheathing from the fly rafter?

The snow load is not a big issue in these parts for most of the winter and since it's only a 12" overhang I wasn't sure what would suffice. I was thinking c) but is that overkill here?

Lastly, I was planning on going with soffit vents and a continuous ridge vent. I'm assuming I would just leave a 2" gap at the ridge when I nail down the sheathing. Is that the right choice and method for venting?

Thanks in advance.

Comments (5)

  • tjdabomb
    9 years ago

    sheathing, 1/2" ply, 50# paper, good to go.

    I'd have to see the overhang to determine if it is even necessary to address. Any work to be done should keep in mind not allowing any of the existing structure to rot, so, any flashing that could be done should be done.

    Rake overhang - show pics

    soffit vents, yes, how?? need to see your site.

    since you will obviously have the roof off, put in a thermatically controlled attic fan. It will keep your trusses and other structural members from becoming brittle from heat, and, make the garage cooler in the summer.

  • plantrookie
    Original Author
    9 years ago

    Thanks for the reply.
    Does your 1/2 ply suggestion mean you dont recommend the 5/8 TG OSB?

    As for the rakes, i have to take them back to the gable trusses. Im thinking of notching in some outlookers...probably easier than building and installing 10 ft ladders on my own.

    Also, I'm still unsure about the need for subfascia at the eaves. Is it necessary?

  • tjdabomb
    9 years ago

    I don't like osb, even with a good roof and paper. if it gets wet, it will swell like donald trump's ego.

    re subfacia, from what you have described, it would only be necessary as a backing for he facia to keep it from warping over time. i guess the decision is more about what you could live with aesthetically since this is not necessarily a structural component.

  • bus_driver
    9 years ago

    If any wooden sheathing gets wet, the sheathing is damaged. If kept dry the OSB will be fine.
    Do a Google search for buckling of roof sheathing. Read up on the subject. Lots of "carpenters" mistakenly butt roof sheathing panels tightly together. Huge mistake.

  • millworkman
    9 years ago

    As bus points out not gapping correctly is a huge mistake. OSB for roof sheathing is fine but you absolutely need to gap it correctly (more so than plywood in my opinion).

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