In my particular configuration, there's a desk surface that extends farter outwards from the poles.
As per the instructions, I need to screw the top of the compression poles into the ceiling (drywall, doesn't seem to be any studs where the poles lie), but I'm not sure what kind of anchors I should be using.
It seems like most of the weight and force should be held by the compression poles, and that there are two concerns regarding anchoring:
* Shearing force: top feet might slip forward and away from the wall
* Tension force: bottom feet might slip in and towards the wall, causing the top feet to pull out of the ceiling (seems like there'd be much less tension than there is shear stress).
The way that the compression pole feet are designed, I need to screw in the anchors/screws through the feet themselves, using #6 screws -- I'm not sure what type of screws/anchors I should be using here.
I also worry that screwing holes into the ceiling where the compression poles are placed will actually weaken the ceiling and could cause the compression poles to punch through -- anyone with more construction smarts than me know the answer to that one?
Last edited by planar; 08-07-2011 at 10:06 AM.
Reason: Added a note regarding shear stress vs tension
Attach the screw mechanism to a larger plate and attach that to the ceiling.
Take a 4"x4" piece of wood and cut a hole in the middle for the screw device to nest in and screw the wooden plate to the ceiling.
You can route the edges or apply a shoe molding to ease the visual transition from the block to the ceiling.
I'd balance the weight side to side as well as possible or install the shelves as seen in the photos, weight to the wall.
"They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety."
B. Franklin 1759