Why did I forget to account for the offset in my drywall screw placement?

[Ivan Seeking]

While hanging some drywall I carefully measured for the position of the screws, which were layed out in a fairly complex pattern due to the water pipes in the wall, and the position of the 2x4s - several cross braces and non-standard separations. After carefully measuring, I realized that I forgot to allow for an offset needed for the next [corner] piece of wall, so I shifted everything by 5/8" and put up the wall. While putting in the second to the last screw, I heard pssssssssssssss, as a little puddle formed at my feet.

Didn't remark one spot.

 

[berkeman]

A couple years ago, I was asked to put up shelves on the four walls of a big new storage room at my kids' grammar school (not the first set of shelves that I'd done for them). It took me a couple weekend days to map the studs, plan the rails and shelves, and mark up the walls. I bought all the materials, including the double-strong vertical metal rails (the kind with the slots for placing the shelf hanger brackets at various heights, and the spaced out screw holes for mounting the rails to the walls). The whole arrangement and inter-connected spacing of the room relied on where I'd planned on placing the rails. It was a work of 3-D art, really.

But when hanging about the 4th or 5th rail (out of a couple dozen), the screw hole happened to line up with a hidden drywall nail or screw (probably put there by Ivan!), so I couldn't use that rail position. But in order to move the rail, I would have to re-plan and re-mark the whole room (yikes!), which I REALLY didn't want to do. But I couldn't skip that screw hole position either, because I needed it to keep the rail at full-strength mounting to the wall.

Luckily I figured out that I could just drill another mounting hole in the metal rail close to the original pre-drilled one, and keep on going. Turned out that a couple other holes had drywall screws/nails under them as well, so it's a good thing that I didn't re-lay-out the whole room -- I probably would have hit some screwheads in the new layout as well.

Nothing is ever simple, eh?