Thread: Fixing a safe to a concrete rib-raft floor

Mine just asked if it was bolted to the wall, I said yes he said thats fine

My E/B/C Safe is 4 12mm dyna's in the concrete and 4 coach screws into crosses in the wall.
It's not going anywhere in a hurry and my inspector didn't question it after seeing it, chem set bolts? Ask them where it says it's necessary in the legislation.

I would get a steel plate fabricated to fit under my safe, weld some bolts to it to line up with yr floor bolt holes in yr safe. Trial fit it make sure it's sweet. Get plate painted with 2 pot epoxy. Once epoxy paint has had a few days to go hard, give it a key with some 120 grit, wipe clean with acetone or similar. Clean concrete, make sure it has a key as well and Sikaflex the plate down. (Use sika multi primer and I think 291 glue)
Put yr safe down on yr plate, do ya bolts up tight and Pepin the tops of threads over.

I bullshit you not, you will need a 100 tonne hydraulic jack to get it off. We stick boats and buildings together with this shit.
You can then stick your wall bolts or coach screws in as well.

This way you will not mess with integrity of yr rib raft.

Originally Posted by Maca49

Mine just asked if it was bolted to the wall, I said yes he said thats fine

i think i know who that was, he has a realistic view on on bolting down a safe.

Originally Posted by Jexla

My E/B/C Safe is 4 12mm dyna's in the concrete and 4 coach screws into crosses in the wall.
It's not going anywhere in a hurry and my inspector didn't question it after seeing it, chem set bolts? Ask them where it says it's necessary in the legislation.

exactly, under the some AO i have had three different inspectors and only one of them insisted on chemset, dynabolts are far more reliable. if you fuck up the chemset they wont hold shit yet a 12mm dynabolt is good for a 500kg rated each. i on average have 11 fixing points so it isnt going anywhere without the key.

Dynabolts are fine. Chemset bolts can be used; however it's not a legal requirement.

Trubolts are even better but you'll need to template the base. and be straight with your hole drilling

My converted ATM weighs over a ton- door is solid 40mm... Not bolted down, not that anyone could ever tell.

Only prob is I'll have to move it in a year for the new house and that's gonna be a mission

10mm self tapping concrete screws are awesome.
Easy to do and you can mount in a corner without risk of cracking the pad as there's expansion when installed

It is funny watching DIYers talk about fixing steel to concrete. Chemset lol

Yeah I'm pretty cognizant of the potential to stuff it up royally, with the danger of a less than optimal attachment being less of a concern than potentially permanently damaging the water tightness of the slab. The intent is to have it done by a pro but first I have to have an understanding of the options, which you guys have been awesome for, so that I am able to give them some idea of what I am actually after, beyond "just fix the safe to the floor." at the last house, that was all the direction I gave (relying on the chippy to know his job) and I ended with a weird mishmash of whatever concrete anchors and adhesives the chippy had left over and it was a big untidy mess-1 dynabolt, 1 drop in anchor, 2 big concrete bolts, a handful of wood screws and a whole lot of liquid nails etc

And three out of the four anchors went straight through the slab and DPC into aggregate

Originally Posted by Mauser308

Ever seen chemset fail? It's rated life span before failure isn't that great - some of the older ones have been known to crumble at the 10-year mark at which time the thing being held down, falls out. I've seen several failures of older chemset products in industrial situations, both due to product failure and concrete spalling out and failing around the adhesive. There are several different types of chemset, three broad classes though - mechanical lock (expansion of the chemset product) chemical lock (glue in) and the combination type.

I've seen the mechanical lock type get whipped straight out of a machine-bored hole using a diamond tip core drill (hole was perfectly smooth so no surface ridges to provide a mechanical lock).

So yep, it's funny watching DIYers talking about fixing steel to concrete especially when pro's f it up on a regular basis...

Sorry Mauser308, I should have been clearer. I was laughing at "chemset" being referred to as one simple product, where as it is one of 100s of chemical anchors. I was also laughing at the idea that some AOs would only accept it as a fixing solution, when they most likely have no idea when to specify such a product. I probably should have been more helpful and suggested using m12x50 screwbolts/Anka screws, to get good hold with minimum drilling depth on the rib raft, while also being easily removed with tools at a later date if needed. I was obviously a little bitter and twisted after supervising a 3rd floor cantilever suspended concrete floor pour in the rain so was less than helpful.

Originally Posted by ubique

And three out of the four anchors went straight through the slab and DPC into aggregate

I would suggest that your Rib Raft floor isn't what it seems if you hit aggregate? Like was said up further rib raft is around 85mm slab with ribs over 2-300mm thick polystyrene pods over damp proof over sub grade(good ground)

I would not worry about damaging the DPM unless it is a basement or below ground scenario with a proper tanking/membrane waterproofing solution. If it simply a house floor slab with a floor height around 225 above ground, the DPM probably had holes in it before you got near it, and while it does a job and is best to avoid damaging it, don't lose any sleep. If you are really worried, a squirt of silicon in each hole before a mechanical anchor, will sort it out. I am more helpful in the mornings sorry. Good luck with the safe!

Edit, I personally detest all chemical anchors and try to avoid using them at all cost. As said above, they are quite finicky to use correctly and I have had many a discussion with a structural engineer over the specification of "chemset" when a more simple mechanical solution exists.