Anyone done a floor safe?

Recently I bought a cheap, fairly large 200+ Kg safe. Its an old night deposit safe so I need to remove the drop points and weld in some plate and line it, then its good to use. A project to fill some isolation time.
That will leave me with a couple of smaller A/B safes surplus. One of which I plan to setup at my Mums, for my Brother who is planning on moving back to Victoria (until he sorts out another place).
The other I think I’ll put at my place in Central Vic, and as I have to replace a floor in one room already…So I’m thinking about building a brick plinth and pouring a small slab, just for the safe between joists and bolting it to that and the joists and then covering it with a trapdoor.
Has anyone done a safe like this? Any flaws/ non compliance issues? The slab would be on bedrock and surrounded by brick walls with no access apart from through the floor.

Its a small house, thats seldom occupied which is why I’d prefer to have the safe concealed even though it will mainly be empty. The house has been broken into 3 times in the last 25 or so years.

Haven’t tried it but sounds like a decent plan to me… kids a work, though.

Haven’t done it myself but one of my brothers did a few years ago.
His was a concrete floor though. He just cut out the section and dropped the safe in and then poured fresh concrete around it.
He got it inspected by the WA boys in blue and they were more than happy with it. He put it in a unused closet in a spare room and then had a couple of light boxes with spare clothes and blankets on top of it so it couldn’t be seen.

I don’t think that you will have any dramas doing it they way you described.

Weld some box sections to the sides of the safe, wet seal it, make up a large form, pour it and set the safe in wet. Will be like hornady interlock!

Moisture would be my biggest concern, might want to go the extra mile with sealing any concrete/brickwork.

Access would be my concern. Getting down on the ground to put stuff in and out. On the other hand when you open the door no worries of guns falling out and landing on your toe or the scope.

A bit of thick black plastic should keep any moisture from rusting the steel.

My last business had a cash safe in the floor. Humid rural part of darwin, I never saw any evidence if moisture ingress or corrosion. We were there for six years. It only had the volume of a milk crate though.

That still equates to a lot of cash.