Concrete Pad for Basketball Court


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Old 06-03-18, 10:26 PM
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Question Concrete Pad for Basketball Court

Hello There!

I have leveled out an area for a basketball court, approximately 30'x50'. To level it, we cut into the slope on the high end and use that and additional fill dirt to build up on the low end. We are working on the retaining wall where we had to cut into the slope, and next will be the court surface. I am considering having a 4" thick concrete pad poured. I have a couple of questions:

1. Since fill was added to build up the level on one side of the court (approximately 4 feet or so at the end, with a "retaining hill" sloping down from there), and the dirt wasn't compacted in small lifts or anything, is there a high risk of the dirt settling over time causing the pad to break and settle? A couple small cracks developing wouldn't bother me, but I need it all to stay together in the same plane.

2. If this is a high risk, what can I do about it?

3. I would like my basketball court to be pretty flat, much less than the standard 1%-2% grade. If possible, I'd like to slope it only an inch or so over the 50 foot length. Is there a reason I can't get away with such a small slope? Will water not draining quickly enough cause any problems for the concrete over time?

Thanks!
 
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Old 06-04-18, 05:03 AM
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1. You can almost guarantee that the fill dirt will be settling for years to come.

2. The only thing you can really do is remove the fill dirt and put it back in properly compacted layers. There are some compaction machines able to do very deep compaction but they are massive and rather rare even on large commercial projects.

3. Ball courts are often made perfectly flat or with very little slope. Water will often puddle showing the low spots. It's why you often see a water roller on tennis courts to get rid of the puddles.

 
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Old 06-04-18, 05:08 AM
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How long ago was it back filled? what type of dirt? Extra thickness with the concrete along with more steel can help it survive poor conditions but I agree it's better to pack the fill correctly.
 
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Old 06-04-18, 05:22 AM
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Yep, it will likely crack. Rent a compactor and embed rebar or 4x4 mesh in the concrete to keep it together when it fractures. You will have lots of puddling on the court if it doesn't slope to the sides. The 50' part should be level but you should really slope the sides. That means the sides would slope 15' each way. 1/4" per foot is recommended on concrete to avoid puddles... but 1% grade is far less than that. It would be about 2" of slope per side. I would recommend you do that.
 
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Old 06-04-18, 08:37 AM
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Thanks for the replies! That's what I was afraid of with the settling. I was hoping maybe it wouldn't be that big a deal with this court getting only foot traffic (no vehicles). I thought maybe the concrete would then be able to bridge a bit with less risk?

I have been watering the area every day for the past week or so to try to encourage settlement / compaction. After 4 days or so if this, I drove all over it to pack it down. It certainly feels nice and firm, and hasn't been getting noticeably lower since then. But it sounds like the settling is a slower process than that....

Regarding using rebar/metal grid, from reading elsewhere I thought that wouldn't do any good for a 4” thick pad, and actually causes problems if the pad isn't thicker. How much would I have to do to be able to have hanging concrete over the one end without issue if the dirt settles?
 
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Old 06-04-18, 08:51 AM
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How long ago was it back filled? what type of dirt?
Oops, forgot to answer these Qs: The majority of the area was filled a little over a month ago using the dirt extracted from the high end. The sod and topsoil layer was stripped first and not used for fill.

Later, we decided to extend the area by a couple more feet, so we brought in another truckload of fill dirt. It was pretty clean and nonorganic dirt. That was just over a week ago, and I've been watering daily for the past week.
 
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Old 06-04-18, 06:55 PM
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Looks like my estimate of the fill depth was a bit on the high side. Today I went out and measured with the laser, and I think I only have 2-3 feet of fill above the original grade.

In the picture:
  • the right side of the court is below the original grade
  • slightly to the left of center court, a small brick standing on end marks the on-grade crossover point from cut to fill
  • half-way between there and the end, a 2nd, larger brick marks where it's 1' above the original grade
  • at the left end, another brick (and a stake) mark where it is about 2' above original grade
  • the original grade also slopes down about another foot of so in the N-S direction, from the near side of the photo to the far side


https://www.dropbox.com/s/5z6frooltd...63602.jpg?dl=0
 
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Old 06-05-18, 05:13 AM
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With a spread like that I assume you have some machinery and you have room to work. I'd move aside the fill and put it back in properly compacted layers. You're putting a lot of money and effort into this court. I would not screw it up by cutting corners on the foundation.

That's a pretty big area to compact and more than I'd want to do with a push vibratory plate compactor or a hopping one. Look into renting a small roller compactor. Just make sure you get one with spikey rollers intended for soil and not smooth rollers intended for asphalt.
 
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Old 06-05-18, 08:40 AM
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I do have some room to work, but not the machinery. I hired out a backhoe guy to do the bulk of the leveling. When he came up short, I got a kind neighbor to help add fill with his tractor. I think I've about used up that favor though... Hate to ask him to rip it out and start over.

Believe it or not, I'm trying to make this court happen on a pretty small budget. Originally, I had been planning to try to go with a good compacted stone base and place sports court tiles on top of that. Then I started thinking concrete might be enough better to be worth considering...but maybe going back to plan A would be lower risk. The compacted stone base is permiable, so probably being placed flat is less of an issue, and if it settles in areas I can simply add some stone and recompact. Once I'm confident no further settling will occur, I could add concrete later if the stone base isn't working out just fine. Hmm. But I was a little worried about trying to level out 1500sf of compacted stone... Any ideas on doing that would also be appreciated!
 
 

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