New In Ground Pool - NJ (Dig has Begun)

Rich D

Bronze Supporter
Aug 3, 2018
960
MA
Thanks. Its looking like they may not get out here till next week to do the steel walls and concrete floor. It is supposed to rain, would that cause any issue to the integrity of the hole?
Looks like you have a good 12 to 24 in of topsoil there. Is that correct? In my opinion they left the spoils far too close to the edge of the pool. they had a nice size excavator there and should have put them farther back and left a good size working shelf. In addition you're going to want to remove all those organics from beneath any deck areas. so that material should have been removed as well to try to help prevent cave-ins. Introducing a little rain to that site is going to create one large mucky mess. If you're expecting heavy rains it might not be a bad idea to lay plastic over the piles and draped down the sidewalls of the pool. This works well as long as the pool doesn't fill with water, then you have no control over the cave-ins
 

jonnyd91

Well-known member
Jul 21, 2020
54
NJ
Looks like you have a good 12 to 24 in of topsoil there. Is that correct? In my opinion they left the spoils far too close to the edge of the pool. they had a nice size excavator there and should have put them farther back and left a good size working shelf. In addition you're going to want to remove all those organics from beneath any deck areas. so that material should have been removed as well to try to help prevent cave-ins. Introducing a little rain to that site is going to create one large mucky mess. If you're expecting heavy rains it might not be a bad idea to lay plastic over the piles and draped down the sidewalls of the pool. This works well as long as the pool doesn't fill with water, then you have no control over the cave-ins
Yeah, they were going to remove all the dirt, but the dump truck kept getting stuck in the yard. So they are leaving it there until they backfill and then will remove it with the bobcats.
I am backfilling with #57 but i have a few questions:

  1. Base on the elevation the steel walls will be 9" above the ground in the front and 16" above the ground in the back.
  2. Im not sure how or what I should use to grade, the water will drain away from the pool given the elevation of the pool.
  3. They said to use some of the dirt to do the grade before they add the concrete, i would need a 5" grade in the front over 12ft and 12" grade in the back over 10ft. Then adding the 4" of concrete would match the elevation.
  4. Not sure if that defeats the purpose of backfilling with gravel.
  5. I think it would cost fortune to do the grade completely with gravel.
I guess ill know better after the wall are installed, but the pool is in the middle of the yard and basically in a "dip" albeit a very gradual one.
 

Rich D

Bronze Supporter
Aug 3, 2018
960
MA
Base on the elevation the steel walls will be 9" above the ground in the front and 16" above the ground in the back
Well... The general rule is "it can never be too high" and I am definitely in favor of "better off a little high than a little low" so hopefully they did there due diligence when figuring your grades but that does seem a bit high from what is shown in the pics wich can be very deceiving.

Im not sure how or what I should use to grade, the water will drain away from the pool given the elevation of the pool
Unfortunately you really have no choice given your soil conditions. The general rule for dealing peaty bogs and organic material is you need at least 24" of structural material on top of stabilization fabric. So in your case it only makes sense to remove all the topsoil from under the deck areas and replace it with a good road base. The top soil can be used for grading outside of any structural areas. This will generate a lot of top soil that needs to be removed. It appears to be very clean top soil and should have some sort of value. @jimmythegreek might be able to advise on its worth for the area but they should at the very least be hauling it away for free .

I think it would cost fortune to do the grade completely with gravel
It will cost a lot more to remove whatever decking settles using that material then remove the unsuitable material, install the proper road base and reinstall the patio. Or you could end up just living with the sunken cracked patio. It is extremely important to give the proper base underneath your patio. I cannot stress that point enough.

Base on the elevation the steel walls will be 9" above the ground in the front and 16" above the ground in the back
If you are going off the back of the pool with a 10' deck then the elevation out towards the shed will be up about 19" from the existing finish grade at the edge of the deck. That could make for some challenging grading out there.

Is the PB going to installing the deck?

Hopefully you are planning on putting in a collar drain. You might be able to run that drain to daylight if you own out past your fence. This would be preferred over a sump pit because it would always keep any ground water at the collar hight without the use of a pump
 

jonnyd91

Well-known member
Jul 21, 2020
54
NJ
If you are going off the back of the pool with a 10' deck then the elevation out towards the shed will be up about 19" from the existing finish grade at the edge of the deck. That could make for some challenging grading out there.

Is the PB going to installing the deck?

Hopefully you are planning on putting in a collar drain. You might be able to run that drain to daylight if you own out past your fence. This would be preferred over a sump pit because it would always keep any ground water at the collar hight without the use of a pump
I’m not following this part at all. I assume the grade from the pool edge would grade down away from the pool. So over a 10ft span it should drop down going toward the shed.
 

Rich D

Bronze Supporter
Aug 3, 2018
960
MA
I’m not following this part at all. I assume the grade from the pool edge would grade down away from the pool. So over a 10ft span it should drop down going toward the shed.
Correct, however the existing grade slopes much faster than the the proposed deck so the hight difference will keep increasing the further away from the deck you go. The plan does not call out the actual elevations of the deck corner close to the shed but a good estimate would be the deck is at 116.65 and existing elevation at 114.85 wich is a difference of 1.8 feet = 21.6 inches
Very nice to see a actual survey plan with existing and proposed elevations. They have done there due diligence and those elevations look correct. The slope to the shed looks to be approx 11%. This is not as bad as I was thinking. To get a good idea you can put a stake at 10' off the pool corner at 21.6" above finish grade and run a string to the shed.
 

jonnyd91

Well-known member
Jul 21, 2020
54
NJ
Correct, however the existing grade slopes much faster than the the proposed deck so the hight difference will keep increasing the further away from the deck you go. The plan does not call out the actual elevations of the deck corner close to the shed but a good estimate would be the deck is at 116.65 and existing elevation at 114.85 wich is a difference of 1.8 feet = 21.6 inches
Very nice to see a actual survey plan with existing and proposed elevations. They have done there due diligence and those elevations look correct. The slope to the shed looks to be approx 11%. This is not as bad as I was thinking. To get a good idea you can put a stake at 10' off the pool corner at 21.6" above finish grade and run a string to the shed.
Thank you so much for that explanation, this makes it much clearer.

they are installing the walls today the height doesn’t look as bad as I thought. Here is a pic:
E06AA14A-36EE-4D81-9DF9-1F1B4A99BD85.jpeg
The back is definitely higher
06B56D62-1557-48C5-91BA-B740655D12C9.jpeg
 
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Rich D

Bronze Supporter
Aug 3, 2018
960
MA
Definitely not as scary as I had first pictured. The shed is much farther back then what I had assumed by just looking at The pics.

Do you have a contractor to prep and pour the deck yet?
 

jonnyd91

Well-known member
Jul 21, 2020
54
NJ
Definitely not as scary as I had first pictured. The shed is much farther back then what I had assumed by just looking at The pics.

Do you have a contractor to prep and pour the deck yet?
I am Actually going to be moving that shed too, so it will be completely out of the way.

yes, he is doing the decking and also putting stone surrounding the spa.

something similar to this

2F3AB0EE-5719-47F6-B916-108832ABE019.jpeg
 

Rich D

Bronze Supporter
Aug 3, 2018
960
MA
I am Actually going to be moving that shed too, so it will be completely out of the way.
If your planning on moving the shed you might want to get a price to remove and replace the fence. This would allow you to just grade out all the extra loam and give you a far more gradual natural looking slope.
 

jonnyd91

Well-known member
Jul 21, 2020
54
NJ
If your planning on moving the shed you might want to get a price to remove and replace the fence. This would allow you to just grade out all the extra loam and give you a far more gradual natural looking slope.
Its about 4500.00 to move it back, just not in the cards right now.

I am planing on backfilling the over dig with gravel.

Are you saying to remove all of the dirt from around the pool and bring in "other material" to bring up the height to the top of the steel walls and grade out everywhere the concrete will be?

Im just trying to envision how to do that given the height and that im going to have to feather it out well past the 10ft around the pool in order to get a good grade that just doesn't drop off.

Their recommendation was to use the dirt to do a nice gradual feather grade, while using a gas powered compactor. He said then they could come back and put a smaller layer of gravel under where the concrete will be and they will use wire mesh when pouring the concrete. There is also a chance the concrete doesn't go in until march, giving the ground time to settle.

I dont want to start grading gravel into the ground past where the concrete will be. So im unsure of the proper way to do all this.
 

Rich D

Bronze Supporter
Aug 3, 2018
960
MA
Its about 4500.00 to move it back, just not in the cards right now.
I was actually just suggesting removing the fence in the fill areas then do the grading then replace the fence to where it was so it would just be labor cost. I suppose if you were to pay for that you would want to extend it..

Are you saying to remove all of the dirt from around the pool and bring in "other material" to bring up the height to the top of the steel walls and grade out everywhere the concrete will be?
yes

Their recommendation was to use the dirt to do a nice gradual feather grade, while using a gas powered compactor. He said then they could come back and put a smaller layer of gravel under where the concrete will be and they will use wire mesh when pouring the concrete. There is also a chance the concrete doesn't go in until march, giving the ground time to settle
That would be the cheap easy way out and would be destined for failure. Compaction of that loam would be difficult and it would still settle after that. The other issue is the loam will heave with frost and the stone around the pool will not, this will crack the concrete or potentially lift the deck beside the pool edge. It is never a good idea to install a patio or walkway over organics. You are spending thousands on the deck and it should have the proper base.

I dont want to start grading gravel into the ground past where the concrete will be. So im unsure of the proper way to do all this
There is no need to install the gravel more than 1' past the edge of the concrete. They would simply grade and pack the loam to the approx finish grade then dig out all the loam in the patio areas. This will leave a nice crisp edge like you now have for the pool only it will be 1-2' higher. This will hold the road base like a form so it can be installed in compacted lifts. If the #57 is the same cost or close to the cost of the road base then you can use #57 for all the fill and have a lot less to compact.

Are you installing a collar drain?
 

jonnyd91

Well-known member
Jul 21, 2020
54
NJ
I was actually just suggesting removing the fence in the fill areas then do the grading then replace the fence to where it was so it would just be labor cost. I suppose if you were to pay for that you would want to extend it..



yes



That would be the cheap easy way out and would be destined for failure. Compaction of that loam would be difficult and it would still settle after that. The other issue is the loam will heave with frost and the stone around the pool will not, this will crack the concrete or potentially lift the deck beside the pool edge. It is never a good idea to install a patio or walkway over organics. You are spending thousands on the deck and it should have the proper base.



There is no need to install the gravel more than 1' past the edge of the concrete. They would simply grade and pack the loam to the approx finish grade then dig out all the loam in the patio areas. This will leave a nice crisp edge like you now have for the pool only it will be 1-2' higher. This will hold the road base like a form so it can be installed in compacted lifts. If the #57 is the same cost or close to the cost of the road base then you can use #57 for all the fill and have a lot less to compact.

Are you installing a collar drain?
where would I put the drain? I’d assume the patio will slope away from the pool?

what kind of material would be used for road base? Can I use crushed concrete?
 
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Rich D

Bronze Supporter
Aug 3, 2018
960
MA
where would I put the drain?
They will pour cement around the base of the walls to lock them in, this is called the "collar". The drain drain would go on top of that. It is to prevent the liner from floating if ground water gets that high and to help with liner replacement.


what kind of material would be used for road base? Can I use crushed concrete?
Yes, crushed concrete makes a great base. This does need to be compacted in 10-12" lifts with a heavy reversible plate compactor. The 57 stone does not require lift compaction.
 

jonnyd91

Well-known member
Jul 21, 2020
54
NJ
They will pour cement around the base of the walls to lock them in, this is called the "collar". The drain drain would go on top of that. It is to prevent the liner from floating if ground water gets that high and to help with liner replacement.




Yes, crushed concrete makes a great base. This does need to be compacted in 10-12" lifts with a heavy reversible plate compactor. The 57 stone does not require lift compaction.
No Collar. They are doing a vermiculite floor. I dont really have any issues with ground water here and below all that top soil is compact sand that hasn't been dug out prior to this so its fairly solid.

The issue I am going to have with the decking base is that no one around here goes through these measures before pouring decking. Im not saying its right, im just saying that they don't do it. Im willing to bet the amount of people that search a forum for answers before they purchase a pool is pretty slim too, so they just have the pool put in and trust the contractor knows best. I have used forums to teach myself for at least 20 years now, seems they may be a dying breed. That said I may have to get creative with this.

I know they wont grade with the dirt and then dig it out to replace with gravel, I basically have 1 day to remove dirt, grade, and backfill. They wont come back 2X as they are so busy, but for that 1 day i have their bobcat and dig foreman at my disposal.

Base on just backfilling the over dig, it looks like more than a full truckload. the depth is only to the top of the soil 36" - 8" for the cement collar.

Screen Shot 2020-10-26 at 12.19.40 PM.png

Then I would have to go back and get another truckload. The logistics of this are becoming complicated.

Right now im thinking to maybe have them pull back the berms around the pool so they give me the 10 and 14 ft for the patio area and then fill that with as much gravel as I can and then after they pour the concrete decking i can come back and grade out that dirt to a gradual grade. I just dont have the time or stress level to be the general contractor on this, so that puts me between a rock and a hard place. I just dont know how much of a grade those patio sections with descend or if I would need to build a temporary retaining wall to hold in the rock. This has been stressing me out for days.