New Build - DIY IGP in Minnesota

jimmythegreek

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Compact some clean stone into the sand to tighten it up. I've done partials before. Dig the whole pool with the big machine to shallow depth. Then dig the central hopper and slope transition leaving some meat on the edges for shaving and support. Pour the collar amd block off the 2 ends with 2x10 amd drill thru the lumber in 3 spots for rebar amd poke 2ft pieces thru. Use 2x4s spiked together across the pool at all the panel joints for support from concrete pushing. After run the mini inside and shape it working your way out. I don't bother with main drains usually. I pour the hopper floor in concrete not poolcrete. Use 2 returns down low on walls pointed down it works better than drains. For plumbing do 2" homeruns for suction side and 1.5 for returns. If you are going to pair returns you can do 2" then reduce to 1.5" for the split off.
 
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MN_poolguy

Member
May 18, 2020
23
Minnesota
Compact some clean stone into the sand to tighten it up. I've done partials before. Dig the whole pool with the big machine to shallow depth. Then dig the central hopper and slope transition leaving some meat on the edges for shaving and support. Pour the collar amd block off the 2 ends with 2x10 amd drill thru the lumber in 3 spots for rebar amd poke 2ft pieces thru. Use 2x4s spiked together across the pool at all the panel joints for support from concrete pushing. After run the mini inside and shape it working your way out. I don't bother with main drains usually. I pour the hopper floor in concrete not poolcrete. Use 2 returns down low on walls pointed down it works better than drains. For plumbing do 2" homeruns for suction side and 1.5 for returns. If you are going to pair returns you can do 2" then reduce to 1.5" for the split off.
Thanks for the thoughts @jimmythegreek ! Based on other posts I'd seen by you (thanks for all those too!) and others I am planning on skipping main drains with two skimmers in 2" for suction. For returns I plan on all home runs in 1.5". Royal had me setup with 3 normal returns - and I was thinking on adding 1 deep return. Is that overkill? Wind blows from the west here and pool basically oriented North/South so was planning 2 skimmers on East side and all three normal returns on West side. Deep return in deep end on skimmer side? I'm seeing info all over the map for flex vs rigid PVC but I guess leaning towards rigid here in Minnesota.

But back to the hopper... I got a good shallow depth whole pool dug this afternoon. Planning on going back tomorrow (after 1-2" of rain tonight) and fine tuning elevation before putting up the wall panels. I like your idea with the 2x10's and rebar to cap the collar pour yet allow for tie in after hopper dig and shallow end wall build/collar 2nd pour. the spiked 2x4 makes sense too as I agree that the rebar through wall panels and even the stakes prob might not be up to the task of keeping the walls in place on the sand through the pour. If you don't mind me asking though - what's the benefit of the concrete in hopper bottom vs pool crete?

Thanks!
 

jimmythegreek

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I use 4 returns min on even a tiny pool. Average pool 6 returns you can never have too many. In your case the 2 would be opposite eachother down low on long sides of hopper for deep returns.
When I do the collar i pour the equip pad and the hopper floor same time/delivery. It let's me have perfect angle back to wall panels amd a place to work from that's dry I deal with clay Crud here usually wet too. I mix vermiculite right in the pool with shovels and a hose no mixer right on the hopper floor when using premix.
 

MN_poolguy

Member
May 18, 2020
23
Minnesota
I use 4 returns min on even a tiny pool. Average pool 6 returns you can never have too many. In your case the 2 would be opposite eachother down low on long sides of hopper for deep returns.
When I do the collar i pour the equip pad and the hopper floor same time/delivery. It let's me have perfect angle back to wall panels amd a place to work from that's dry I deal with clay Crud here usually wet too. I mix vermiculite right in the pool with shovels and a hose no mixer right on the hopper floor when using premix.
I plan on 4 returns at the corner step/bench combo for a pseudo jacuzzi effect, 3 returns on opposite wall from skimmers, 1 or 2 deep returns, and 1 return for pressure side cleaner (auto cover). Thats a lot but I like the idea of home runs for everything for redundancy in case a pipe gets compromised. I wish I could do the hopper floor and equipment pad at same time as I'm already paying for a pump on site. I'm hurrying the footer pour a bit as my over dig is close to an existing patio and with some recent heavy rains I'm getting really nervous about erosion and sinking and just want to get it shored back up ASAP.

Attached a pic of where we are at tonight. Everything nearly ready for the collar. The two panels (an 8 and 4 ft section) will be removed after the pour and will be dammed off using @jimmythegreek suggestion to stop the concrete with 2x10 and rebar through the middle. Then I can get back in with the bobcat or an excavator to get the deep end dug.

61456901019__0B61F3CD-1CED-40A6-B8D5-E29DBE9C190D.JPG
 

jimmythegreek

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Looks really good nice job on bracing. I do that on every build with a line pump. Regular concrete just needs bottom bracing. Make a plywood ramp so you can protect the overdig when digging in pool. I park the skidsteer amd have bucket to edge of pool amd dump right into it with the mini. It sucks shoveling out whoopsies from behind panels
 

MN_poolguy

Member
May 18, 2020
23
Minnesota
Looks really good nice job on bracing. I do that on every build with a line pump. Regular concrete just needs bottom bracing. Make a plywood ramp so you can protect the overdig when digging in pool. I park the skidsteer amd have bucket to edge of pool amd dump right into it with the mini. It sucks shoveling out whoopsies from behind panels
Thanks! I added the top angle 2x3 braces as the outer a-frame braces are useless in the sand at this point for plumbing the walls. Just trying to get the walls are close enough to plumb to be within the adjustable range of the turnbuckles after the collar is set. One more question now that I think of it - I'm targeting 8" of collar. Royal documentation said 5-7", everywhere else said 8-10" or 10-12" deep. 8" seemed like a happy medium?
 

MN_poolguy

Member
May 18, 2020
23
Minnesota
@jimmythegreek Got the collar poured yesterday! All went well with no movement in the walls - the bracing worked great. So if I could bother you again... Plan is to plumb pool (with Rigid PVC), backfill (with something) and eventual Concrete pool deck into bullnose coping. Trying to decide on material/methods for backfill - i've searched this forum and seen the strong advocates for gravel/stone for backfill. I have piles of sand in my yard from the dig I was considering as well. Here are my thoughts and would love input:

1) Use excavated sand for backfill lifting in layers and tamping in between. Thoughts - I like the idea of sand protecting my PVC plumbing, using the material already on site.

2) Bring in 57 stone or something similar with high compaction and low voids. Thoughts - Makes me nervous having rock surronding the PVC to potentially wear on it. Also unsure if surrounding sand/dirt could wash into any backfill voids over time and sink those areas (and the patio on top of that). Obviously this is more expensive too.

Help! :)
 

jimmythegreek

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How sandy is the soil? It's ok to use some around pipes but I never do it that way. I have a rule everybody follows. What comes out never goes back. I cant chance it waaaaay to expensive and time consuming to fix settlement issues. I do pavers almost exclusively the sub base is everything. I pay about 400 for a tandem of clean stone delivered so I'm not afraid to use it heavily. I do a drain on top of the collar usually and I use septic grade filter fabric that's 12ft wide. I cut in half and lay it from the collar concrete up the sides of dig onto top level. I use small amounts to pitch the drain all the way around to a sump pit, then backfill all clean stone to plumbing or above. I wrap the fabric over the stone and tuck tight to wall cutting excess. I then use clean stone to get to the level for my upper coping collar height amd form that. I pour that then I use road base for all the rest in small lifts. If your doing concrete you can use clean stone for all of it even sub base
 
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MN_poolguy

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May 18, 2020
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Minnesota
How sandy is the soil? It's ok to use some around pipes but I never do it that way. I have a rule everybody follows. What comes out never goes back. I cant chance it waaaaay to expensive and time consuming to fix settlement issues. I do pavers almost exclusively the sub base is everything. I pay about 400 for a tandem of clean stone delivered so I'm not afraid to use it heavily. I do a drain on top of the collar usually and I use septic grade filter fabric that's 12ft wide. I cut in half and lay it from the collar concrete up the sides of dig onto top level. I use small amounts to pitch the drain all the way around to a sump pit, then backfill all clean stone to plumbing or above. I wrap the fabric over the stone and tuck tight to wall cutting excess. I then use clean stone to get to the level for my upper coping collar height amd form that. I pour that then I use road base for all the rest in small lifts. If your doing concrete you can use clean stone for all of it even sub base
It's really sandy - like could almost put it in an hourglass if it wasn't for the various sized of river rock mixed in (from 1 inch diameter to 1/8" diameter. I believe there to be very little soil if any in the sand.
 

jimmythegreek

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If its bank run type you could use it for the deck base. Has to have plenty of stones of various sizes mixed in like road made material that's what packs and holds tight. Against the walls you will never get a good compact down low. Clean gravel is only way to go up to existing sub base
 

MN_poolguy

Member
May 18, 2020
23
Minnesota
If its bank run type you could use it for the deck base. Has to have plenty of stones of various sizes mixed in like road made material that's what packs and holds tight. Against the walls you will never get a good compact down low. Clean gravel is only way to go up to existing sub base
Hi All,

Well now I've had a problem. With things going pretty well, go in the remaining open spot in the walls to dig the deep end yesterday. We are (were?) going for a 8'6" deep end which seems to be standard for pool builders in our area. As luck would have it we hit ground water at about 8 feet though will try to measure exact depth of water table today. Really bummed. We are completely sand down to this point. I'm so surprised because our neighbors 5 houses down had a pool professionally finished a week ago - also to 8'6" without hitting the water. Our sump pump has never run in our house ever (15 years and counting!) We did have a massive rain storm 6 days ago that dumped 6-9 inches in one night in our area. I'm sure this has raised the water table some and our neighbors got there pool in and filled a few days before that rain. I've had the cover pump running in the deep end for 20 hours now and it dropped he water level from about 8 inches to 2 inches high in the deep end while running nearly constant.

So hear are the options I've thought of or read about to this point:

1) try to overdig the bottom by a 12inches or so to 9'6" and throw a foot of gravel in up to water table top and put a drain down there (maybe the main drains i'm not using?) dig a trench back out the shallow end opening and run PVC from the drains to a cheap pool pump to keep the water out during construction. Try to build as normal - though the sandy walls are such a challenge even without this curveball.

2) try to dig a sump well around outside of the concrete collar (perhaps to end up in future landscaping). I have no idea how to do this though with the tools/equipment I have on hand.

2)Keep myself occupied with other projects over the next week or so and see if the water table drops by next week with more hot and hopefully dry weather in store here.

3)Though I have a liner for 8' 6" depth in my garage, call the excavation quits at 8' and shape it appropriately for that depth pool. Install the liner anyway (no main drains) accepting it will be very wrinkled at the bottom. Until the next liner in 10 years or so.

4)Order a new liner for an 8' depth and eat the price of the wasted liner (ugh).

I'm not entirely sure I can do 8' right now without any issue either - still might be an inch or two into current water table as I know I'll confirm this morning with some fresh measurements. Such a bummer and just kind of sick to my stomach to be honest :(
Untitled.jpg
 

jimmythegreek

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Get a 2 foot piece of 12" pvc the black corrugated type. Dig a hole or pound it in the bottom removing sand as you go. Get a cheap sump pump with vertical float amd drop it in and get the water out amd downhill from the dig. Leave it in running as you build pumping water out. When you start doing vermiculite work around the hole. When your ready for liner quickly dump 3/4 clean stone in hole give it a whack with the hand tamper amd have a bucket of vermiculite mixed and ready. Patch it and install liner. It's done all the time this way.
The sump pit to the side is the best fix long term amd future but in sandy soil you need an auger on the machine to do it a 12 minimum an 18 is best.
You can also overdig and lay a square of PVC in and perf it running back out but your walls are up too much effort now
 

MN_poolguy

Member
May 18, 2020
23
Minnesota
Get a 2 foot piece of 12" pvc the black corrugated type. Dig a hole or pound it in the bottom removing sand as you go. Get a cheap sump pump with vertical float amd drop it in and get the water out amd downhill from the dig. Leave it in running as you build pumping water out. When you start doing vermiculite work around the hole. When your ready for liner quickly dump 3/4 clean stone in hole give it a whack with the hand tamper amd have a bucket of vermiculite mixed and ready. Patch it and install liner. It's done all the time this way.
The sump pit to the side is the best fix long term amd future but in sandy soil you need an auger on the machine to do it a 12 minimum an 18 is best.
You can also overdig and lay a square of PVC in and perf it running back out but your walls are up too much effort now
@jimmythegreek Thank you! If i went the 12" PVC route do I just plant that sucker right in the middle of the deep end? Any gravel needed with this option or just proceed as normal if the sump pump/pipe clears the water? As the for the square of PVC - I could do that as I have two panels still open on shallow end to get the mini excavator in and out since I have a bit more work do in there once I figure out how i'm handling the water situation. I've established the current water table depth at 7' 10". So need to clear about 10" of water to be able to add my 2" of pool base to bottom. Would I have minutes or hours or days to get that liner in before I start having problems with ground water through the pool base (was planning premix throughout)?
 

jimmythegreek

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Plant it out of the way anywhere is fine. You should put a skim of gravel in bottom to not suck sand up. With sandy soil the water usually comes up from bottom easily no holes needed in PVC. Sand may migrate in that way. Adjust or improvise as needed. The water will lower on it's own as you dry the area out you may not need it as you get closer and with rain may get worst then better again. How solid are the hopper sides are you having issues with sliding or cave ins.
 

MN_poolguy

Member
May 18, 2020
23
Minnesota
Plant it out of the way anywhere is fine. You should put a skim of gravel in bottom to not suck sand up. With sandy soil the water usually comes up from bottom easily no holes needed in PVC. Sand may migrate in that way. Adjust or improvise as needed. The water will lower on it's own as you dry the area out you may not need it as you get closer and with rain may get worst then better again. How solid are the hopper sides are you having issues with sliding or cave ins.
@jimmythegreek
Its been 90 degrees and dry for 5 days now so the sand is really dry and crumbling. Luckily I hadn't shaved them to fit yet so i have a little crumbling room. I do have the collar in all the way around the walls so unless things get super ugly the panel walls shouldn't move - just getting the proper shape in the sand will be a problem. I'm thinking I'll be needing to wet them and tamp sideways just be for applying vermiculite. Maybe even some wood forms or something, working up a foot at a time with the pool crete - Not going to be easy.
 

MN_poolguy

Member
May 18, 2020
23
Minnesota
@jimmythegreek
Its been 90 degrees and dry for 5 days now so the sand is really dry and crumbling. Luckily I hadn't shaved them to fit yet so i have a little crumbling room. I do have the collar in all the way around the walls so unless things get super ugly the panel walls shouldn't move - just getting the proper shape in the sand will be a problem. I'm thinking I'll be needing to wet them and tamp sideways just be for applying vermiculite. Maybe even some wood forms or something, working up a foot at a time with the pool crete - Not going to be easy.
Groundwater level has been stable since saturday so i think it safe to say its not going to recede much. Going to start the battle with it this evening and hopefully finish excavation in the next day or two. I'm on to thinking about trying to put premix on these crumbling walls. Just the three sides of the hopper I'm worried about. I know I'll have to keep them damp and tamped somehow but I was thinking about tamping in some sort of erosion control blanket or geotextile on the three steepest slopes to help it hold shape. Figured it can't hurt if I lay the pool base on top of the blanket/sand combo?
 

MN_poolguy

Member
May 18, 2020
23
Minnesota
Groundwater level has been stable since saturday so i think it safe to say its not going to recede much. Going to start the battle with it this evening and hopefully finish excavation in the next day or two. I'm on to thinking about trying to put premix on these crumbling walls. Just the three sides of the hopper I'm worried about. I know I'll have to keep them damp and tamped somehow but I was thinking about tamping in some sort of erosion control blanket or geotextile on the three steepest slopes to help it hold shape. Figured it can't hurt if I lay the pool base on top of the blanket/sand combo?
@jimmythegreek the groundwater/sand combo is putting up more of a fight than anticipated. I have the bottom of the sump pump at the about the 9.5' - Can probably get it a bit lower but real hard to scoop sand out of the bottom of the tube with out it being quickly replaced by new sand. Have gravel on hand to use and am trying to use that to get the water to follow lower sand to my sump pump. But I spoke with William at Royal pools today and he was very helpful. I really have no problem with going to an 8' depth instead of 8' 6" other than avoiding massive wrinkles. William says Findlay tends to cut their liners tight anyway so I may not even notice any wrinkles from a 6" adjustment just to the hopper depth. We came up with a revised dig sheet to retain or even slightly steepen the hopper back and side walls and increasing the footprint of the hopper bottom and depth to help use up some of that liner material. This will also I guess help with diving board placement as we'll be able to move it backwards a bit. So I still have some significant water mitigation to do but this seems MUCH more doable than trying to remove that last 6" of water logged quicksand.

This problem is making my hair gray(er) - soooo looking forward to getting past this!
 

jimmythegreek

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That's not a bad approach I think it would work. Have you tried banging the PVC in with the mini bucket amd then scooping the sand inside out. What's the water level like and what kind of pump are you running? Should dry out with a little time amd a good pump if theres no rain. I can't say I've ever battled a hopper i couldnt dry out enough to do the floor and liner. Ibe had to wait days but it dries eventually. Stick a 2nd in there if needed and pump far away. I've strung larger pvc together for 100+ feet to get water away using discharge hose to drop into the pvc
 

MN_poolguy

Member
May 18, 2020
23
Minnesota
That's not a bad approach I think it would work. Have you tried banging the PVC in with the mini bucket amd then scooping the sand inside out. What's the water level like and what kind of pump are you running? Should dry out with a little time amd a good pump if theres no rain. I can't say I've ever battled a hopper i couldnt dry out enough to do the floor and liner. Ibe had to wait days but it dries eventually. Stick a 2nd in there if needed and pump far away. I've strung larger pvc together for 100+ feet to get water away using discharge hose to drop into the pvc
@jimmythegreek Well long weekend but I think I’ve emerged victorious over the groundwater and sandy slopes! Got control of groundwater Friday. Managed to get the sump pit down about 26” and dropped a sump pump Down there. Ran a 1.5 flex pvc from it under grade out the pool and to the catch basin in our backyard. Using the mini excavator we were able to methodically dive the bucket slowly into the saturated sand around the sump pit and slowly draw it back while shoveling in gravel before the sand could replace it. I think we managed a 10-12” layer of gravel around the hopper bottom this way. After this we were finally able to get the top of hopper bottom dry. Also Tee’d off to a foot valve which I planted in the gravel for hopeful future use when maybe replacing a liner years down the road. Ended up framing a hopper bottom and pouring in concrete to lock up the situation. This worked great as then we were able to final shave the sand hopper walls and get the pool base premix down on the 3 steep sides of the hopper. The sand slopes actually were not a big challenge since it was all undisturbed - it actually was quite hard packed for verm to sit on. Back on track again! Thanks so much for all your help!!