pouring a small slab

This project is actually indoors, but I posted here because the thread had to do with concrete. I have a small dirt floor crawl space (8x3 1/2) I want to pour a concrete floor in. It is unvented and only has a 2x2 access through my basement wall and is 5 ft high off the floor. I am going to mix these 80# bags in a 5 gal bucket one at a time with a drilI and attachment. I will split the crawl in half with a board in the middle and pour half the space at another date .How quickly do I need to mix and install these 8 bags before the whole thing starts to set up? I imagine the temps will be 50-60 in there.Thanks

 

I don't see how you are going to mix 8 bags of concrete or cement with a drill, even one at a time, Either use mixing pan & a shovel or rent a 1 bag mixer. The mixer is the better idea. If you are using Quickcrete Ready Mix or Portland cement with sand, you have enough time get it done before it starts to set.

 

I can't see using a drill being a viable method either. I've mixed a good bit of concrete in a wheel barrow over the years but a mixer makes life easier! I have a 1/2 bag mixer I bought from harbor freight 23 yrs ago, it pretty beat up but still works

 

If you can get a light source into the crawl space, you'd be better off mixing the mud in a mortar tub (using a flat-bottomed shovel or spade) right in the same area instead of mixing outside and having to transport the fluid concrete through the small opening, placing and finishing it once you get it in there. Especially since you have a fair amount of head room.

Having done it a few times, I can say that moving heavy, mixed concrete in a 5-gal. pail isn't a lot of fun.

 

The bag is 80 pounds and once you start to add the water it will feel like 800. Be careful adding the water as all of a sudden you will have soup. Bridgeman's mortar pan right in the crawlspace is what I would do, then just shovel it into place.

A plastic vapor barrier underneath is a good option and decide on any slope before you start. If water gets in there from outside or failed plumbing, where do you want it to go, perimeter drain or sump pit?

Once you start placing the mix you will lose sight of how deep you want it. For that size space a board on each side should be fine.

As you place each batch just push it to the height you want so as you progress you will have a flat surface behind you. Once one half is in place you can work off of pieces of plywood to reach out and work the gravel down a bit. Being a crawlspace I doubt you need a real fine finish.

Bud

 

if you don't have space to mix a large batch, just mix it loose to give yerself more time.low temp will help with time and if ya like wet it as you go for more time, be sure to tramp it well to take air out. might be just well off with pavers and sand. you'll have a couple hours if mixed loose.

 

my guys do it every week i don't know whether or not they consider it ' fun ' but its honest work 1/2" drill mixing seems more difficult than the mortar pan to us,,, other than that, your method's fine to me - mix, place, & finish 1/2 against a bulkhead then do the other 1/2 later on when your sore back's better

 

sorry...wrong post...meant to start a new thread

 

You don't need a new thread. 28 days.

 

A lot depends on how thick the concrete is, they say the concrete in the Hoover dam is still curing. Generally the concrete is dry enough for use after a few days.