exterior partition wall

[mnicholet]

Today I inspected this home. These pics are in the garage. The exterior walls non-bearing are installed on OSB sheathing, essentially acting as flooring on a minor foundation threshold/curb, some areas have no curb and the OSB is equal to the slab. As you can see, I could pull the OSB sheathing out in some areas therefore the bottom plate was somewhat floating. I told my client to talk to the city building inspector as the final occupancy was not yet granted.

I had some discussion with the onsite contractor, he left to make some phone calls regarding my concern. Then, the local building inspector just showed up to conduct final occupancy. My client asked the question regarding the OSB sheathing and the hot water tank installed in the garage with no pan and drain. The City Building Inspector said it was all fine due to the OSB sheathing is acting just like flooring and the hot water tank does not require pan/drain as it is a non occupant area.

Anyways, my concern is the fact that the OSB sheathing is not under compression in some areas therefore the bottom plate is somewhat floating. Furthermore, the hot water tank is located next to the occupant door into the building with no threshold (see the pic). From a performance evaluation is there not potential for the hot water tank to cause water damage under the door sill? Your opinions would be greatly appreciated and any recommendations on how to write this up would be helpful. Thank you.

[mnicholet]

Is there not some load on that wall right of the garage? Eave overhang, gable truss? In my opinion there is. Building inspector says no...

[rbero]

The trusses span the garage and the weight is on the front, center if there is one, and back walls the right wall holds it own weight.

[Joseph W. Keresztury]

Mark, all exterior walls are load bearing.
Doesn't make sense that the OSB is loose, but it does look like just a short piece coming loose, meaning the slab could be that wavy. Especially since the garage slab floor should be sloped for drainage. A concern should be that an untreated material, the osb is in direct contact with the concrete (not even any felt underneath it). It already looks like it's rotting. If that was 3/4" OSB, they coulda , shoulda used 1x4 treated/ wolmanized material, glued and nailed to the bottom of the plate.
Was that a truss framed roof or stick built?
Your city inspector told your client that the OSB was ok because it was acting as flooring? Yeh, it's ok for flooring (subflooring) when it's on interior wood floor joists that aren't exposed to moisture or sitting on exposed concrete (as in this case) to be eaten up from the reaction to the direct contact with concrete. And those sole plates must not be anchored to the foundation as required if the OSB fillers from under the plates are coming loose.

[jford1]

OSB should never be in contact with concrete and any moisture. The 2x sole plate should be anchored to the concrete foundation. All exterior walls are considered "bearing". Some have a heavier load, but all are bearing. In my state, the water heater would be elevated on a stand 2' off of the ground(fire issue with car fumes and the pilot light). That OSB underneath the plate is absolutely HORRIBLE!