I’m confused... if they built the area up, what is the retaining wall for? To keep weight of pool from displacing the dirt it is sitting on?
I would insist that they do what you originally asked them to do.
Can a concrete pad support AGP?
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I would insist that they do what you originally asked them to do.
Woodstock1234
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JoeSelf
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You need to dig down to undisturbed soil & level for the pool. If they just thru in some soil and compacted it will settle and then the pool could fail. If they used stone, it would need to be done in small lifts and compacted until the area was level.
If the area was built up it needs to be compacted some how. There are different methods depending on what the soil is but it needs to be done correctly or it'll settle.
What they did is they first removed the grass and then they added what he called a crushed compacting sand/stone (I forgot what grade or exact name is) and then they compacted, added and compacted and rinsed and repeated until it was level. They added some sand I had on top and compacted again. The retaining wall is for where the high side just stops. Its and L shape that needs the retaining wall.. I will take pictures tomorrow. But I wanted to use Ground contact pressure treated lumber for them to build the wall and want to know if that is sufficient?
I'll post pictures of the area tomorrow as it is raining today. I also plan to add 4" concrete blocks in the area for the legs, level with the compacted area.
I'll post pictures of the area tomorrow as it is raining today. I also plan to add 4" concrete blocks in the area for the legs, level with the compacted area.
That seems to me like a reasonable way to build up a surface for a pool if compacted well, but I'm not an expert.
Ground contact pressure treated lumber is for, well, ground contact.
So that should be fine, but yes it will not last forever.Here is the thing. There is nothing inherently wrong with placing a pool on properly compacted fill. The issue is, how do you know you have properly compacted fill.
You cannot just "put in dirt and compact it really well" even if you are using the correct fill material, you cannot just "compact it really well". Soils have a optimal moisture content (percentage) where they will compact to their maximum dry density. If you have more or less water in the soil, you can compact it until the cows come home and it will never reach its maximum potential density. Then 2 years down the road when it dries out some, or it rains and it gets a little wetter, with your pool sitting on it, it compacts some more. No bueno.
Some soils are more forgiving than others. The goal in construction (most of the time) is to reach 95% of the maximum dry density. Some soils have a flatter curve. What that means is that if your moisture content is between say 4% and 9% you can still hit that 95% compaction. Other are really sharp, and if you are more than a 1% off you will never reach 95% compaction.
So how do you know these curves and measure the compaction? You hire a geotechnical engineer (sorry, I left that field a long time ago and no longer do site inspections). They run compaction curves (Proctor tests) in the lab and then measure the in place density in the field.
Now we come to point #2. Isn't that a lot of overkill you say? I'm building a pool, not a garage. Ahh, there is the difference. A pool is HEAVY. More psi loading than a garage. Also, a garage on a slab is much more rigid, and is able to bridge minor variations in the substrate. An ABG is a big flexible bag of water with almost no structural rigidity. If something starts to settle, the whole bag o' water is going in that direction, with disastrous results.
Which brings us to point #3. A concrete slab is only as good as the ground under it. As I said above, a slab can bridge some very minor imperfections in subgrade preparation. But chances are it will crack, and shift, and that is worse under a pool than a small amount of soil settling. To have a slab that will not crack or shift, you basically have to prepare the ground as you would for a pool anyway.
I know I won't be able to get an engineer, but I am trying to get it as good as possible for my ground. I'm hoping they come back today so that they can put in the retaining wall and I can take pictures. I also bought 4" thick concrete blocks that I plan to have them put in flat at all of the leg locations like the attached images from another posters thread..
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We did a circular paver patio so we can have patio chairs out when it's not pool season and otherwise the pool is set up for summer
Here is an update, they're currently working on the ground leveling. They have put up a retaining wall made from Ground contact Lumber and they are putting in the 4" thick concrete pavers at each of the leg locations. Then they will add another layer of compacting material and compact it all level..
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Okay update: the ground is prepped and ready. I am open to any more suggestions or ideas.. I plan on renting a compactor possibly to compact it one last time? Is that a good idea or should I avoid that since I might crack some of the 4" concrete blocks? Also I still plan to put 2" x 12" pressure treated lumber at each leg per the instructions despite already having the concrete blocks there. Is that a bad idea? I'd rather go overkill if it's not going to harm anything .
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Will the entire bottom of the leg fit on the blocks? If so, I’m not sure why you would put wood down, or even where you would put it?
So I put the two concrete blocks based on a post by @sammckin and it does look like the u shaped legs fit, but the reason I am thinking to do the pressure treated lumber is because the instructions call for it and it's a softer less abrasive material. Plus I am hoping it would avoid any potential cracking to the pavers even if they're 4" thick. I plan to sit a tarp in between the concrete blocks and the lumber and another tarp over top of the lumber in between the legs and the lumber. Is this a bad idea or just overkill? I'm okay with overkill as long as it's not detrimental..
Oh and the wood would sit right on top where the concrete blocks are. The raised height of 2" is good too because I plan to use the 4'x8' foam insulation and a waterproof flooring underlayment which will add 2" in height under the pool floor..
Personally I think that is overkill. The 4” thick blocks are highly unlikely to crack, nor will they rot.
I think it will do more harm than good. The pool legs will be more prone to slipping off the wood if they are elevated like that.
I'll take heed and just use the blocks praying they don't crack.. I am considering one last compaction with the a plate compactor. I just need to find one with a rubber plate pad. Just to be sure it's solid
If the blocks are on firm foundation, it would take a lot to crack them. Don’t worry!
Okay I have 2 more questions rather than starting a new thread I'll ask here..
1) I purchased a water level and found that two pavers are 1/2" low off level and 6 are 1" low off level. Is this not with the tolerance and should they be corrected or is 1" fine?
2) since the pavers are flush with the ground is it okay to put foam boards under the pool liner but on top of the ground (not the pavers of course) and be okay or is that also needing to be flush with the pavers? I prefer to just sit it on the ground and not have to raise the pavers which are sitting nicely flush with the ground.
1) I purchased a water level and found that two pavers are 1/2" low off level and 6 are 1" low off level. Is this not with the tolerance and should they be corrected or is 1" fine?
2) since the pavers are flush with the ground is it okay to put foam boards under the pool liner but on top of the ground (not the pavers of course) and be okay or is that also needing to be flush with the pavers? I prefer to just sit it on the ground and not have to raise the pavers which are sitting nicely flush with the ground.