We are planning to install a wall-mounted bookshelf on a wall (3.5 x 2.4 m with a door at one end) that is made of 12 mm fiberboard on 20 mm tongue and groove wood. The shelf is of the type with vertical wall rails with 8 screws in each, and we intend to install four rails. Two considerations:
Firstly, the load-bearing capacity. Will it work to drill through the fiberboard into the tongue and groove wood if we tighten the screws hard? Will the wall rail dig into the fiberboard from the load? The rail is U-shaped with the "legs" against the wall. It's not the end of the world if there are marks, but the shelf needs to be stable.
Secondly, the electrical wiring. The house was built in 1949, with the electrical system partially renovated in the last fifteen years, but it's unclear how it runs. How was electrical wiring typically installed in these types of walls back then? The wall has an outlet and a switch near the door, and I guess they run straight up to the attic from there. The adjacent wall has an outlet at floor level about a meter from the corner. Could the wiring for that outlet be running across the wall where we want to place the shelf? It would mean 8x4=32 screw holes in the wall. I've tested with a cable detector of a cheap type from Jula, but it feels like a lottery whether it detects anything.
Many also point out the fire hazard with fiberboard, but tearing them down and installing plaster seems like it would spill over into also doing all other walls in the room (with windows, radiators, etc.), and it becomes a big project just to put up a bookshelf.
Firstly, the load-bearing capacity. Will it work to drill through the fiberboard into the tongue and groove wood if we tighten the screws hard? Will the wall rail dig into the fiberboard from the load? The rail is U-shaped with the "legs" against the wall. It's not the end of the world if there are marks, but the shelf needs to be stable.
Secondly, the electrical wiring. The house was built in 1949, with the electrical system partially renovated in the last fifteen years, but it's unclear how it runs. How was electrical wiring typically installed in these types of walls back then? The wall has an outlet and a switch near the door, and I guess they run straight up to the attic from there. The adjacent wall has an outlet at floor level about a meter from the corner. Could the wiring for that outlet be running across the wall where we want to place the shelf? It would mean 8x4=32 screw holes in the wall. I've tested with a cable detector of a cheap type from Jula, but it feels like a lottery whether it detects anything.
Many also point out the fire hazard with fiberboard, but tearing them down and installing plaster seems like it would spill over into also doing all other walls in the room (with windows, radiators, etc.), and it becomes a big project just to put up a bookshelf.
Just screw it in with a screw that goes through both the rails and the tretex so it reaches the råsponent as it should. Tretex may eventually shrink a little over many years, but not in a way that will cause it to fall down, and as you mentioned, if it leaves marks, it doesn't matter.
The electricity should go straight up or down from the outlet.
The electricity should go straight up or down from the outlet.
Thanks for the response. Yes, I'll use screws that go through everything including the battens.snuttjulle said:
I've also done some digging around in the insulation in the attic above and I think I have a handle on the existing wiring (it goes, as you say, straight down from the attic to the junction box and switch), so it seems fine.