Shelf above window separated from wall. How exactly are these shelves mounted? 2017 Outback.

pthomas745

FB thread this morning, with pictures of the Outback shelf over the passenger window fallen off the wall.

Hard to tell what failed here:  the wooden "bracket" or one of the screws.  The question becomes: how are these shelves attached to the side walls of the trailer.

I wound up reading through the "Grab Handle" thread that has much discussion of the construction of the side walls, how the door is attached, and how the outside grab bar is attached.

https://tab-rv.vanillacommunity.com/discussion/8012/grab-handle-ideas/p1

During that discussion, an owner @Bill@ndRox managed to wangle a schematic of the side walls from NuCamp.  The conversation focused a bit on "EGS", which is apparently a thin aluminum "framing" material around the door, and..maybe...the window.  (Something has to hold the window frame in place).  There is one quick mention of the shelf over the window, but the question was not answered.

https://tab-rv.vanillacommunity.com/discussion/comment/107197/#Comment_107197

This is one of the schematics from that comment.  There does seem to be "something" framing the window.  Would this be the same sort of framing found around the door where the outside grab handle was mentioned?  Does the shelf attach to the side wall the same basic way the outdoor grab handle is attached?

MuttonChops

"EGS" material/layer is used at all the primary cabinet screw attachment areas.
For example:

Attached PDF has a nüCamp technical drawing.

pthomas745

@MuttonChops I had a nice morning running through the construction threads and finding all this hard work everyone did for us.  So, am I correct in thinking of this EGS layer as something like the "flashing" of a window install?  In one of the comments in that thread you said:  "Quick web-search suggests EGS sheet backing metal is 20 - 25 gauge which gives the screws a bit of extra bite."

I'm having some trouble sorting out how "thick" or solid that might be.  (I've seen the measurements in various charts.) 

Thanks again for that interesting "grab handle" thread that everyone worked on.  Very interesting.

MuttonChops

pthomas745 said:
. . . am I correct in thinking of this EGS layer as something like the "flashing" of a window install? 

In one of the comments in that thread you said:  "Quick web-search suggests EGS sheet backing metal is 20 - 25 gauge which gives the screws a bit of extra bite."

From the construction side the EGS is 'flashing like' while window flashing is for water protection and the EGS seems to be used for mechanical reasons.   I'm not a Mechanical Engineer and do not know the forces involved - - - but that EGS layer does seem to do a great job holding screws.

This is one of the better forums for useful information, active members, and detailed discussions.

Maxcamp

OP, its a little to hard to tell from photos what was there, not having the same model.
Is the vertical board under your failed shelf just for photo purposes or was it part of the construction?  Was the failed board horizontal or vertical?  I assume horizontal- can you help us correlate the screw in wall above the ply ledger strip to its location on the maple shelf or other piece, and the screw hole below the ledger strip to its partner?
One hopes these locations correspond with the EGS strip.

In the first photo: was the raw plywood ledger strip visible or hidden?  5-ply is not cabinet grade and is weaker than 9 to 13 ply baltic birch which they should be using for anything in the Tab.  They may have screwed the ledger in place from the outside face of the EGS (likely 22 to 28 ga thin galvy sheetmetal strip).  

In the second photo: looks like solid maple or pine shelf which they pocket screwed to either the ply ledger strip or through the the composite wall hopefully into the EGS strip. Two issues:
a. they undoubtedly overdrove the pocket screw and split out the shelf during installation, which later split further and failed.
b. The black screw sticking out the shelf looks like a coarse thread drywall screw and could be used into the weak ply edge but is incorrect to hold in the sheetmetal.  Any drywall screw in sheetmetal has too coarse and thread and will cam out with vibration or torque.  

Dadoing the solid shelf to receive the ledger, and screwing up through the face would have been a stronger connection than end grain.  Brackets, dowels, t nuts, or other methods would have made a stronger connection.

In our 2021 Boondoggle we see many failures of cabinet joinery which required fixes. Blowouts and widespread veneer damage  from lack of predrilling, blowouts and stripping of overdriven fasteners, stripping of square drive heads by using 100% improper Phillips bits, and more are rampant misconstruction errors.

(edited on desktop since first post.)