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Thread: Soft spots in clay

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    Tim23's Avatar
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    Soft spots in clay

    Hello All,

    I hope I am asking this question in the right area..... We are preparing the ground where the AGP will go. It is a 27' round. Everything is going good with the leveling etc.. We live in south Louisiana "who dat" and the ground here is either wet most of the time or hard as a rock. The area I am putting the pool is mostly clay base. The only problem I am having is that I am finding soft spots in the ground. Most likely where a tree was years ago. If I stand on the area I sink down a good bit. We had an Intex soft side 24' pool in the same location and never noticed them. Now that I am putting in a standard metal AGP I wanted to clear the area and level it correctly. What I am wondering, is there anything I can do about the soft spots? Could they be a problem? I have only found 2 and they are about 3' sq. One of them is in the path of where the lower rail will go around. Any advice would be helpful. Thanks Tim
    Delair 27', 52" round AGP. 19,300gal
    Waterway 22"/1.5hp pump, 2 speed/sand filter, BBB
    My BBB motto.."LESS IS MORE WITHOUT ALL THE CHORES, SO FOLLOW TFP AND IN THE END, THE POOL OWNER SCORES"!

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    Mod Squad Bama Rambler's Avatar
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    Re: Soft spots in clay

    SInce you have a clay area your best plan of action is to rent a vibrating plate and compact and fill the places that are soft. You'll want to compact them till they won't compact any more. Then fill the sunken places not more than 6" at a time, compacting as you go until it's level with the surrounding area.

    While you're there I'd compact the entire area slightly larger than the pool just to make sure there are no surprises once the pool is set.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
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    Re: Soft spots in clay

    I agree. You want to do everything possible to prepare the foundation. It is the most important step in setting up an above ground pool. I would go the whole way around the perimiter of the pool and make sure the ground is thoroughly compacted so you don't run into trouble after it's all set up and you find one side has sunk.

    Good luck and if you need any help, just ask.
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    Re: Soft spots in clay

    Hi. Tim,

    Welcome to the forum! Soft spots from a stump can be a real PITA. They hold water sometimes just like a swimming pool!!!

    The best answer is to dig down and install a french drain to allow the water to escape.....that's seldom practical.

    If your clay soil is similar to mine, the absorption rate is simply almost nonexistant and those stump holes can take a year or more to dry out.

    I believe if you simply do a first class job of leveling and then building up a base of gravel, etc. to spread the weight evenly across the soil you will be fine.

    Compaction, unless you completely remove the wet soil all the way down to undisturbed earth and then refill, will likely have little effect on the soft spots other than bring the water up to the surface and make it even softer. There are many types of soil and even different types of clay but yours sounds like it is going to do best left undisturbed.

    How long have the stumps been removed?
    Dave S. - Forum owner
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    Re: Soft spots in clay

    Thanks for all the advice!!! You guys rock.... The stumps have been gone for about 2 years. I had green grass in that spot without any sinking etc. When I removed the grass to put the Intex soft side pool up and brought in sand for it to sit on I didn't have those soft spots. But now that I removed the sand to re-level the area and expand for the new AGP and with the rain we have had etc they are showing up.

    I did dig one of them out to see how far the sloppy mess went.....WOW is all I could say. It was still soupy at the end of the shovel handle. So I dumped sand then clay then sand to fill it back up. The ones in the middle area I'm not so worried about. Its the one that is in the path of the lower track that concerns me. I think, if I'm right I will make sure the upright foot does not fall in that area? Otherwise everything going good. I talked with a buddy that puts in roads and driveways and he said here in our area (louisiana) this is a normal thing. He has to go back and repair areas like this about every other year. I will try a wacker packer on those areas also. I have a hand tamp but it just laughs at it. LOL Thanks again. Love the site. Tim

    Oh one other question... Did I read right that it's better to put the pool on natural ground rather then using sand if you don't have to?
    Delair 27', 52" round AGP. 19,300gal
    Waterway 22"/1.5hp pump, 2 speed/sand filter, BBB
    My BBB motto.."LESS IS MORE WITHOUT ALL THE CHORES, SO FOLLOW TFP AND IN THE END, THE POOL OWNER SCORES"!

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    Re: Soft spots in clay

    Tim,

    One of the guys better versed in AG installation will be along soon. Meanwhile, it seems to me the addition of some sand/fine gravel and building the pool bottom just slightly higher (than ground level) would make sense.

    Easy to level and better drainage. Disregard this as just speculation, tho. Others will chime in soon.
    Dave S. - Forum owner
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    Re: Soft spots in clay

    Tim, welcome to TFP!!

    You are certainly correct, these guys R-O-C-K

    You are also correct in that you definitely! DO NOT WANT one of the uprights to be within ~ 2' of the stump hole!

    Follow Duraliegh's advice on treating them before the pool goes up.

    It's better to have the blocks under the uprights on 'virgin' ground, but you DO want at least 2" of sand under the liner. The sand should be compacted, as per Bama, and footprints and compaction ridges should be troweled out, by hand, - BEFORE the liner is dropped!

    Congrats to the Saints
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

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    Re: Soft spots in clay

    I started out in this industry as an excavator and one of the hurdles that I have had to overcome is poor soil conditions due to excess water in the soil. When you dig the dirt out and try to recompact it will act like a bowl of jello. You compact here and over there it pushes up, so you go over there and compact and the other area pushes up. This is called pumping. The common practice to fix this was to dig down and remove the wet soil a few feet below the grade you want and then put a foot or so of gravel in. Then you would need to find good dry fill and pack it in 6" lifts over the gravel to obtain and adequate base. This would become a long drawn out process and in some cases was very hard to accomplish due to access.

    I asked a road crew foreman how they would overcome poor soil when building a new road and thier solution was much simpler. They would impregnate the poor soil with Lime. Lime is a key ingrediant of cement and it will dry out wet soil. We started to use Portland cement in bags bought at Home Depot or any other supplier where you can find cement and it worked great. In one instance the dirt was so wet that it poured out of the bucket of my machine and would just ooze across the job site. I added about 10 bags to a truck load of dirt, mixed it all up with the machine, and walked away from it for a day. On the third day when we returned, the soil was completely dry and ready to compact with no pumping. This can be done on a small scale as well. Just dig the dirt ouy a foot or so below your grade and mix in the Portland. Let it sit for a day and then recompact it back.

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    Re: Soft spots in clay

    THAT'S A GREAT IDEA!!

    While we usually just shovel out the 'mush' and then stone it, this sounds like a good way to deal with larger areas
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

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    Re: Soft spots in clay

    I agree sounds like a great idea.

    Just an update... A friend of mine came over to look at the problem. He is the one that does road beds and driveways etc. He also said by me trying to dig out the wet clay and refilling it that it caused more problems. As SCEADU said this causes a pumping effect when tamped or walked on. But on a good note he did say with all the rain we have received here in Louisiana that its not unusual for a soft spot to show up. He also said that it should dry out when the ground around dries out more.

    I'm gonna try what SCEADU suggested to do just to be safe. Thanks for all support and help. Like I said before. GREAT people great site. I belong to many forums and I am a Mod on a few. I have to say this is the first forum that I have ever signed up for and as a newbie I got such a warm and great response. Keep it up!

    Tim
    Delair 27', 52" round AGP. 19,300gal
    Waterway 22"/1.5hp pump, 2 speed/sand filter, BBB
    My BBB motto.."LESS IS MORE WITHOUT ALL THE CHORES, SO FOLLOW TFP AND IN THE END, THE POOL OWNER SCORES"!

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    Re: Soft spots in clay

    Its more than an idea fellas. Its tried and true!

    With all the rain we have been having in the Atlanta area, we "flash" all of out digs with Portland after they are dug. This will frorm a "crust" on the dig and lets the rain run off without soaking into the the excavation. It make it easier for the steel, plumbing, and shot crew to do their jobs in a rainy season.

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    Re: Soft spots in clay

    Update...

    Ok, First what I realized is going on with my pool foundation.... I figured out that when we put our Intex 24' pool up, we brought in 9 yards of sand in to help level the area where the pool was going. When I cleared the grass and leveled the ground with the sand I hadn't disturbed the ground/dirt much. SO... Now that we are putting in our 27' AGP I removed the sand and started digging out to make sure the ground was level. Since the area is almost all clay and there were trees growing there years ago Im sure thats the problem.

    I believe the old pool and sand was keeping the water from soaking in the clay etc.. What I am dealing with now is the rain and the fact the more I walk on the area the worse it gets. I did get some cement and mixed it with sand and put it in the softest areas. The thing about clay is when its dry its hard as a rock. When it gets wet its like gum. Some spots are like walking on jello. We have been dry for about a week now so some areas did get somewhat hard.

    My question is this. one of the most important things is to make sure the ground is level right?? Well as I said before some of the bottom rails will fall where the soft areas are. Im afraid when I dig down to put my upright block level with the ground that the ground will still be soft or get soft. What I plan to do is to dig down enough to try and get hard clay. Then put some cement and sand in the hole. Then put crushed limestone in the hole and a block or two if needed to bring it level. I know the area will dry out once I get everything put in and backfilled. One thing I need to know is if the area where the bottom rails run is level and solid so that the walls wont shift, sink etc..Would it be a big deal or problem if the main area inside the circle is not perfectly smooth before I put my sand down? I plan on using the sand to make it smooth. But because the ground is still soft in spots that when I walk on it I leave foot prints and I cant dig it to well.

    Thanks for any help
    Tim
    Delair 27', 52" round AGP. 19,300gal
    Waterway 22"/1.5hp pump, 2 speed/sand filter, BBB
    My BBB motto.."LESS IS MORE WITHOUT ALL THE CHORES, SO FOLLOW TFP AND IN THE END, THE POOL OWNER SCORES"!

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    Re: Soft spots in clay

    Yes. Use the sand to level the area. I wouldn't suggest using all sand if there was a foot difference from side to side but to take out the minor irregularities is what it is for.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    Re: Soft spots in clay

    duraleigh, Thanks for the info. The ground is up or down in spots about an 1/2 inch to an inch or so. Some of the area is perfect but some is a little high but like I said not by much. As the water in the clay shifts and dries out the level changes a little. Now I am only talking about the middle area. I am aware that the wall area must be level.

    As soon as my wife puts the pics on the computer I will share them. This morning I woke up to a LAKE!!! My son was able to run his remote control boat in our new pond!! So at 6:30am this morning I was digging out an area to drain the water off.

    My wife said "honey why don't we just get some fish and make it a fishing pond"! LOL
    I didn't care for that statement due to all the hours I have digging and digging and draining etc... LOL

    Thanks a bunch
    Tim
    Delair 27', 52" round AGP. 19,300gal
    Waterway 22"/1.5hp pump, 2 speed/sand filter, BBB
    My BBB motto.."LESS IS MORE WITHOUT ALL THE CHORES, SO FOLLOW TFP AND IN THE END, THE POOL OWNER SCORES"!

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    Re: Soft spots in clay

    Hang in there. I imagine once all is said and done you will be lounging on a pool float with your beverage of choice thinking how worth it everything was.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
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    Re: Soft spots in clay

    Fixed the pics in other post, sorry

    Tim
    Delair 27', 52" round AGP. 19,300gal
    Waterway 22"/1.5hp pump, 2 speed/sand filter, BBB
    My BBB motto.."LESS IS MORE WITHOUT ALL THE CHORES, SO FOLLOW TFP AND IN THE END, THE POOL OWNER SCORES"!

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    frustratedpoolmom's Avatar
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    Re: Soft spots in clay

    You would be better off using a Photobucket.com type site to upload the photos there and then copy and past the "IMG code" into a message here. Choosing the "large" size for your pics when you upload to those sites.

    It's much easier and you don't have to worry about resizing the file, etc. and the pictures are much easier to view.
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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    Re: Soft spots in clay

    Ok lets try this again! LOL Photobucket does not seem to like me. LOL

    Click on the picture and it will give you a bigger one!!



    This is what I'm working with!!



    Closer look at the soft spot.




    Our new lake




    Draining the lake



    DEEP



    Did a test with portland cement mixed with clay. Seemed to do the trick. I will know more once it dries.
    Delair 27', 52" round AGP. 19,300gal
    Waterway 22"/1.5hp pump, 2 speed/sand filter, BBB
    My BBB motto.."LESS IS MORE WITHOUT ALL THE CHORES, SO FOLLOW TFP AND IN THE END, THE POOL OWNER SCORES"!

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    Tim23's Avatar
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    Re: Soft spots in clay

    Well..... Tried to work on the pool this weekend. I guess I am snake bit. LOL

    We covered the area with with a 40x40 tarp to try and keep the rain we got on last friday. I thought that would do the trick. But no luck. The water just ran under the tarp in areas and we ended up with water under and on top of the tarp. So this weekend I swept the water off the tarp and out of my base again!

    Started laying it out to dig for my pads. Well dug my first hole to set my block and it just filled with water and was just way to soft. So I am back to square 1. We have had to much rain here in Louisiana. We decided to stop and let the ground dry some more. I covered it back up and tried to seal it off even better.

    Yesterday(monday) we go almost 2" of rain again. So now we have water on the tarp and looks like under again.

    We are expected to have a week of clear weather so maybe it will dry some. Its just frustrating to say the least.

    If it wasn't for this site I would go stir crazy! As everyone has told me....Don't sweat it because you can't swim for a while anyway. I guess I just want to build it before the weather get to hot and we get into those afternoon thunderstorms.

    So I will try again this weekend. Wish me luck! Thanks for all the support.

    Tim
    Delair 27', 52" round AGP. 19,300gal
    Waterway 22"/1.5hp pump, 2 speed/sand filter, BBB
    My BBB motto.."LESS IS MORE WITHOUT ALL THE CHORES, SO FOLLOW TFP AND IN THE END, THE POOL OWNER SCORES"!

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