Last week, I had a backhoe come put and excavate for a slab/driveway I want to pour. Maybe some background info would help.
I take care of the equipment for the Lion’s club here in town. The equipment is kept in 2 storage sheds that were put up on a vacant lot near my house. But when they built the sheds, they never put any sort of driveway in. This is fine most of the time – The ground is fairly solid.
Two problems cropped up which have changed things. First, the neighbor replaced his sewer line, which ran in front of the shed doors. And the last 2 times we’ve had carnivals it’s rained. Some of the equipment had to be pulled into the sheds with tractors. This tracked a tremendous amount of mud into the sheds, which I’ve been shoveling out seemingly forever. So I got the board of directors to approve putting in a driveway.
Basically the plan was this: I wanted to put in a conctrete slab about 2′ wider then the doors,and about 6′ out. Then I figured I’d put in a gravel drive the rest of the way up to the street. (The street is about 2′ higher than the slab)
But I’m kinda getting off the point. After we dug out for the slab, we’ve had several heavy rains. So the hole we made now looks like a mud volleyball pit.
Once the water dries up in the hole, should I do anything before I form and pour? The ground where the slab is seemed fairly solid, so I didn’t think I needed to compact it any. Years of running over it with trucks should hopefully have it packed down well. But will the water sitting in there matter?
BTW – The slab is NOT over where the guy put in the sewer. The gravel part will be over that.
I have a skid steer with a bucket there, so I can scrape out any dirt that’s washed in. Just didn’t know if I should go farther.
Any suggestions would be appreciated.
One should never generalize.
Replies
I don't know your soil type there, Boss, but as a generalization (had to throw that in), I would spread and compact 4 inches or so of crushed rock over the fairly smoothed out, dried out soil.
Crushed rock most always serves as a good base, but it's also fairly easy to screed out so you can end up with a consistent thickness on your concrete.
Edited 5/11/2003 11:56:23 AM ET by Notchman
Just curious - What good would the crushed rock do on an outside slab?
I can see where it woul be benificial to have rock under an interior slab, to keep moisture away from the underside. But I can't see any benefit to doing it on an exterior slab. I'm the outdoor type. As soon as a woman mentions commitment, I'm out the door.
Boss,
I'm not a concrete expert but have had good luck doing what Notchman said. I think the crushed stone does two things here: mainly, when well compacted, it forms a really solid base to pour on, which you don't have with the mucky hole. Secondly, it is sort of a simple way to dry things out. You can spread the load right into water and mud, compact it, and pour all in the same morning.
I have been on schedules when we've set up footings and foundations, when I really did not want to take a chance on the trenches drying out (especially this time of year) and poured stone into frost trenches that were more like rivers, and had good results. I'm thinking it was a lot worse than what you're doing, and it had to hold up ICF walls to boot.
Dog
Agree with last post. I would slop out the dirt and get back to original excavation. Either pour the concrete or add some crushed material to bring up subgrade for desired slab thickness.
I would suggest you consider installing a trench drain, as you stated 2' difference in grade, I think you know in a hard rain where water is going to end up. Instead of a broom to sweep out dirt as you are currently doing you might need a floor squeegy.
You can either form and pour one yourself and fabricate a steel grate cover, or you can purchase precast poly-concrete drains that already have predetermined pitches built in. The ones I have used come in 3' sections with end caps and knocth outs in bottoms that will recieve 4" drain tile. The sections interlock and you set them level, you can get grates that slip right in. They do offer grates that lock but I have never used them, can't believe that sooner or later locks are going to be a problem.
They are a bit pricey but labor saved in forming and fabricating grate seems to me a far better way to go. They usually can be purchased thru suppliers of drain tile ,sewer pipe, precast manhole ring and covers.
I think I have the drainage thing whipped. (Hopefully) While the backhoe was there, I had him dig out a 4' wide swale that drains the slab off to a ditch. And the exterior slab will be about 2" below the slab inside the building.
Water was running into the front of the building before this project, due to poor drainage. One of the goals of this slab is to correct that problem.
I thought about putting in a concrete drive all the way to the street and adding a trench drain. But I figured that would cost 3 or 4 times as much. And I don't want to waste the club's money. Draining a trench like that would also be difficult, as it would require a lot more trenching to get to where it would drain to daylight.
I was also concerned about putting a driveway over a bunch of utilities. Never know when someone is gonna come along and dig it up again.Democracy must be something more than two wolves and a sheep voting on what to have for dinner. [James Bovard]