Home Forums Hunting & Shooting Hunter's Campfire Concrete pad for safe, drying time?

For crying out loud we run traffic on 3250 PSI concrete. We build bridge decks with 3750 PSI concrete.

Matt you could form it yourself, get some HD-50 in 50 lb bags and make it yourself. You can mix HD-50, place it and be driving on it in a few hours.

That's what I'm thinking too........




Casey

Keeping them in precisely the correct place is the trick.

also, it was poured today, along with the outside stuff, from a pre-mix order,delivered.

I'll have to move the safe from house 1 to house 2 when the time is right.

right now, looking at 15 day placement, 19 day anchor install. kosher?

in 28 days you have the specified strength, but NOT the ultimate strength. It cures for a LONG time. You can generally drive on it after 7 days.

I just poured a 9 yd slab and missed a couple of anchor bolts. I drilled and put Red-heads in after 4 days and used an impact to tighten them. They held fine.

As for moisture releasing, once it is gray, you have most of the moisture out. If it is still green, it is still wet. Depends on your climate and how you treated it after the pour. If you have kept water on it for days, it will dry slower but cure much harder and stronger. If it is warm and sunny, it will dry in 5-6 days.

My main slab is 18" thick (to support my lathe) and the approach is only 4" thick. The 4" stuff was dry in 4 days, the 18" stuff took all of 7 days.

We often started framing on a slab the 2nd day after it was poured. We tightened the anchor bolts with a rachet and I have never seen one pull out- just don't get carried away.

Its gonna be hard to place a heavy safe over a few bolts. Anything over two bolts would turn out to be a serious job! For instance, if there are four bolts to be placed in the concrete, they better be exactly the same dimensions as the pre drilled holes in the safe, and you would need some kind of lift or crane to lower it directly over the bolts without damaging the threads or the bolts themselves.

I think he plans on drilling into the slab to put anchors in them and then bolting the safe down instead of leaving the bolts and nuts sticking out from the safe floor.

otter---proper sidewalk mix is 4000psi---- not for strength but to withstand the elements better. Web

Making the spacing for anchor bolts is pretty simple work with a plywood jig you build to fit whatever spacing you have on the safe. Stick your bolts thru the holes in the safe, place plywood up against bolts, smack with big hammer, drill holes in plywood where marks are. Build you a jig to hold the plywood level with the floor/concrete and bolt your anchor bolts to the plywood at the right depth..pour concrete and stick the jig down into the conrete etc....math is way overated lol. Same way we do it on everything from a 4" column to a 8' diameter smokestack with a circular pattern.

However picking up a safe and setting it down on anchor bolts inside a house isn't going to be super easy.

Drill it would be my choice.

That's interesting on 3250 psi concrete. We can't even pour a curb or fill a pan stair here with less than 4k. The only bridge we did with a concrete deck required a lot more. We failed two test pours in a row before the concrete people got it right, but it was a swing bridge - maybe that's why.

Here they are finishing the base for UtahLefty's safe:

Concrete never stops curing, for something of that weight I would defiantly wait a few weeks. If he put rebar in the little slab if it cracks it won't be a major deal, if he didn't put rebar in it, wait a little longer, if it cracks that crack will really open up on you.

Good luck, Matt!

2 weeks is a really, really safe bet. He's covering his ass.

When we pour concret, it's 7 days before we can drive on a standard mix.

geez we frame the day after the pour and I'm shooting hilti pins into a a deck the 3rd day. Its a 1200 Lb safe folks, he's not driving a 100K Lb truck over it.

Your thinking too much about this.


ML

So what safe are you going to put on the slab ?

I guess that was kinda my point. When we pour a bridge, we can drive equipment on it after 7 days, without doing breaks.

You can put you safe on it after 24 hours. If you want to be really safe, wait a few days before you drill the holes in for the bolts.

For highway use, 30 days before use is a good benchmark. It might be longer for your application (anchoring a safe) since the concrete and moisture within, might cause the safe's metal bottom to rust.

If you can put something between the concrete and safe to stop the cold from transfering to safe. Will help inside moisture control. Plastic sheet against slab and a 1/2 plywood spacer.Keep safe at room temp so moisture doesn't form inside. You should be able to drill thru the safe floor holes, ply and concrete and install red heads. the bolts can even be angled so they won't pull out if someone tries to lift by prying. 7 days is plenty up to 90% cured.

Again, 7 days is considered the min. for loading/drilling/stressing etc.. We build on them and backfill against them (carefully) after 7 days. 7 days if it were mine, keep plastic over it the first 6.

I'd say as soon as this thread dies, you should be good to go.