I have a wall that's made of plasterboards mounted on metal studs. I have mounted two DVD cabinets (each 22kg) and an LCD TV (40kg).
To mount all this, I installed 6mm thick MDF panels across 5 of the metal studs using 15 self-tapping screws per panel (3 per stud), through the existing 12mm plasterboards and into the studs.
+-+---------+-+ | | | | | +---------+ | | | | | | +---------+ <-(a) | | | | | +---------+ | +-------------+
The top panel supports the cabinets, with 3 hollow wall anchors going through the MDF and the drywall, two on each side and one in the middle.
The middle panel supports the TV mount, with 4 hollow wall anchors. The look a bit like this, but much longer (the head part before the extending part being 18mm).
That means that both the TV and the DVD cabinets are putting load on both the plasterboard and the MDF, which theoretically means the load should be evenly distributed.
This has all been assembled and mounted a few days ago.
The wall is seeing some movement, the right-most plasterboard has moved forward around the (a) point by about 2mm, which is also the distance between the bend and the corner of the wall.
By my calculations, with the load evenly distributed across 5 studs, that's 16 kilos per stud, plus the MDF weight (183x183x0.6 at roughly 700kg per cubic meter), thats 18 kilos per stud.
I think the bulging is mostly due to the right-most plasterboard bulging under the pull from the bolts and the MDF being thin enough to deform as well, but that the load is still taken by the studs and there should be no fundamental structural issues.
Can those metal studs take 18kilos each? Is the bulging a worrying sign? How much movement is normal as the wall adjusts to the additional weight? And have I missed something fundamental in this installation?