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In my garage, the builder looks to have installed an OSB wall adjacent to the Living Room. The other walls are just drywall and studs whereas this one has OSB and then drywall on top of it. Is there any reason why they would have installed this wall?

I'm looking to cut a utility access panel into this wall so checking if there's any negatives to cutting through this wall.

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That is probably what's called a shear wall. It's laterally structural to support the building's side-to-side forces.

Penetrations in your shear wall must adhere to different restrictions than other walls and you may need to consult an engineer to verify. However, I suspect that if you're just removing enough osb to accommodate a small sub panel you're probably fine, you may need to block around it.

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The OSB board could be a “shear” wall, it even has solid blocking in the joist space above the wall. However, I doubt that it is because, 1) OSB board is very weak in lateral shear, 2) minimal nailing at sole plate, top plate and edges of panels, and 3) panels are installed vertical and unblocked.

More than likely it was installed for backing for hanging garden tools, etc. or sound control between spaces.

Remember, any wall between a garage and a habitable living space must have fire rated gypsum board (5/8” Type X or 1/2” Type C) on the garage side.

If you cut holes in the wall to mount things, (or to install a utility access, like you say) will void the fire rating.

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    I'm not sure why you think OSB is weak in shear. It's the strongest of the 4 or 5 common sheathing products you see in residential construction. Vertical installation is ideal if one prefers to not have to add blocking.
    – isherwood
    Commented Jul 23, 2018 at 21:13
  • @isherwood Name a structural material that’s worse.
    – Lee Sam
    Commented Jul 23, 2018 at 22:15
  • Well, plywood. I don't intend to get tangled in another pedantic argument with you, though. Feel free to clarify if that's not what you meant.
    – isherwood
    Commented Jul 23, 2018 at 23:03
  • @isherwood The trouble with googling for info is that you get outdated info. Did you read the first paragraph? The preface says, “The information contained in this article is old and outdated..” The Code does not allow OSB board for seismic loads in zones D, E, and F. Also, if you check Table 2306.3(2), you’ll see 1/2” OSB board with 11 ga. staple (they don’t even list a value for nailing) at 4” o.c. is 150 lbs. per foot for 7/16 “ head. Likewise, Table 2306.2(1) has a value of 235 lbs. per foot for staples at 4” o.c. for 15/32” plywood. You can’t believe everything you read on the internet.
    – Lee Sam
    Commented Jul 24, 2018 at 0:41
  • @isherwood BTW, As per your request, that clarifies what I meant.
    – Lee Sam
    Commented Jul 24, 2018 at 5:48
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I am going to say that is most likely a load-bearing wall. That looks like floor trusses above. A sheer wall is usually on exterior walls, rake walls or where a roof truss would have lateral force, in which the shear wall, we used was panels with osb nailed off between the roof truss but not the wall itself. Or it may be just for better insulation purposes.

I would simply ask an inspector about the panel since I assume you will pull a permit. :)

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Punch a wall with OSB + Drywall, and a wall with drywall only and not only you will see the difference on the resistance, plus you will see how easy is to fix dry walls with OSB under it; With only drywall,, you'd have to change the whole board probably. That may imply even taking out cornices and/or dust covers.

Plus, the OSB provides better thermal isolation, bracing, and it can even replace diagonals, although I still place them in corners.

Drywalls witout OSB is a "no no" in my book at least; those are just doll houses.

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