[hijack]I lived in a house with a particleboard subfloor. I know this because we had to replace part of it due to water damage.[/hijack]
A old friend of mine hid his safe and ALSO bolted it to the floor. I belive he bolted down a couple of 2x4’s and then bolted the safe down to them. Rather than directly to the floor. You can’t access the 2x4’s without moving the safe so that is at least a deterrant for thieves. (IMHO if a skilled thief wants anything bad enough, there’s no guaranteed protection for that item.)
His house had a set of 4 drawers with a linen cabinet above - built into the wall. He removed the bottom 2 drawers but left the faces intact. So when he needs to access his safe - it’s cleverly hidden behind the false drawers.
I thought it was a fantastic idea if there’s an area of the house that allows for that.
One little thing to keep in mind, if you every have a fire, your safe will be at the bottom of the rubble pile. The weight will drag it down as the floor weakens. This makes for a special danger to firefighters who would fall through the otherwise intact floor.
Water damage can cause the floor to fail too, but more slowly. The weight per square foot is higher than most floors are rated for.
After it’s been in place for a while, you may notice the doors near it won’t close properly, and you might see cracks in the drywall.
You drill a small hole. Then you slide in the fastener with the big circular plate on the outside and the basket looking part going into the wall. Then you tighten the screw in the center of the fastener and it pulls the center of the metal “basket” closer to the wall. This causes the basket to squash and spread out, firmly squeezing the drywall between the deformed basket and the front plate. Drywall is weak if you are punching perpendicularly into it, but fairly strong if you are pulling parallel to the surface.