It seems that when the ventilation space was built next to my wardrobe, they used double plasterboards without an air gap towards the apartment's wall. I am now planning to hang a 14 kg mirror on that wall. Since I can only access the space through a small hatch in the wall, I find it difficult to measure the exact thickness of the wall. I would like to use a molly plug to hang the mirror, but I'm not sure if there is one for this thickness of the wall. I believe the two boards are about 30 mm together.
Does anyone have tips on which plug I should use?
The two boards photographed from inside the ventilation space.
The hatch in the wall I have to open to take photos from the inside.
