Mixing Sand and Concrete ????

[Aranon]

I have a unique installation in that I have to install part of my pool over a sidewalk in the back yard that I can not dig up. :mad: This means I will have to have my buttress free 2" support channels on top of the sidewalk. I am going to use 2" Dow Chemical Blue Styrofoam for my bottom, but I have to fill and level between the 2" channels.

I planned on using sand but after seeing it run between cracks in the fence I think it would run out the sides and my foam would break. Then I though of dry mixing concrete with the sand and hope that the concrete will set up with the moisture in the air and set the sand so it would not run. I might even lightly mist it after I level it off with the channel/uprights before I put the 2" foam on top of it.

My question is, has any one mixed concrete with sand like this and if so what is the suggested ratio and which type of concrete do you suggest.

My other option is to level the ground (with sand- I mean I already have like 10 yards of the stuff already) and place an additional layer of 2" Styrofoam between the 2" channels and then add my other 2" foam bottom on top of the foam and channels. I think Dennis said this is how they install pools on concrete floors in showrooms and conventions centers/shows.

What do you all suggest the best way would be. (And don't say dig up the sidewalk and do it right) If I use the sand/concrete mixture, what would be the ratio and any other suggestions would be helpful.

Please help, I am ready to do it this weekend. I already have all my blocks leveled (at least the ones not on the sidewalk). Please help. I need it.

Oh, and I am taking lots of pictures of the whole process if anyone is interested in how it turns out.

Thanks,
Aranon

[matt4x4]

OK, here's my 2 cents:
DON'T build up sand to put your pool on, not a good idea...
Is your sidewalk level or not??
If it's level, you could use it as a starting point, otherwise build up on top of it with a good solid sub base and compact well, but not using sand. Burriing the sidewalk is not really an issue unless it was built improper and has tendencies to heave with frost - then you have to remove it.
Use the sand for your cove.

[Aranon]

yes my sidewalk is level and i have the columns support 2" channels sitting on them and leveled 16 x 16" blocks on the other side. This leaves me with 2" of nothing under the pools and between the column support channels that are under the pool along with the pressure plates which have nothing under them.

I have to add 2" of something to bring everything level with the 2" galvanized metal channel / column supports before I put my 2" of blue Styrofoam on.

I don't want to pour concrete so I was thinking of a sand and concrete dry mixture that would in theory harden somewhat to keep the sand from running out. I will put patio blocks around the rail to keep it level and supported between the channels and on the ovals.

What do yall suggest? :confused: :confused:

Aranon

[matt4x4]

Well, sand and concrete would definitely harden, but depending on the ratio can also crumble easily.
Have you thought of trying crusher run or screenings as they're called up here in canada - it's essentailly the fine stuff that falls out of the gravel crusher, the bits are jagged, and teh fine dust hardens nicely with moisture, put this around the edge and under the wall taper it down to ground level and do the inside of the pool in sand.

[Aranon]

Anyone know the ration of mixing sand to concrete for bottom???
:confused:

[JJ in Tx]

1 part Portland Cement with 8 parts sand NO WATER
you don't want to use something like Quikcrete it has the pebbles etc in it you want the Portland Cement it is just fine powder.
Hope that helps
JJ

[Aranon]

Thanks, Have you done this before and did it work pretty well for you. I didn't realize how fine the sand was until I saw where it ran out thru the cracks in the fence. I have little sand dunes on the other side. I could just picture all the sand running out around the edges and my pool sagging.

[JJ in Tx]

No I didn't have to do that on my install. Mine is round, here is what I did:
Leveled and compaceted existing ground, then I build a pressure treated 2x4 frame that was larger diameter than the pool basically 24' pool 28' frame, this frame got anchored to the ground with lengths of rebar spiked thru it and then back filled with masons sand. I would add some sand and compact it, add sand compact ..... then layed out the patio stones for the wall uprights added some more sand and compacted, assembled pool. It may be unorthodox and a lot more work but the pool hasn't had any issues, I haven't lost any sand from underneath it or anything like that. Personally I'm not familliar with how a oval goes together, maybe if you could post a picture or 2 of the problem we can brainstorm up a workable solution to your problem.
JJ

[Aranon]

I was hoping Dennis would have commented on this. I'm sure he has had this problem at least once.

Aranon

[Aranon]

JJ ,
How long before the sand sets up with the Portland Cement added to it. I would imagine that it only sets up enough to keep the sand together and not spreading or running off instead of a strength type bond. Am I thinking along the right lines. I was thinking of either building a 2x4 wall or using metal angle between the channels and pouring about a six inch rail of concrete to go between the rails and fill the middle with sand to level it off even with the upright channel supports and then I would have a firm level base to lay my 2" foam board on. I am thinking this way the sand wouldn't run out. Please advised. Thanks.
Aranon:eek:

[hrsdennis]

Hi Aranon, I have been reading but had nothing to add as I have not done this before, with the sand and concrete. On our indoor oval displays that need to be built up 2" we use styrafoam.

Your way sounds good as long as it sets hard and you have a way to keep it in place.

Later, Dennis

[Aranon]

I'm so confused. I almost want to move the pool out to the middle of the yard and set it up conventionally. Nothing is level where I am putting it. One end on the sidewalk the supports set right on top of the concrete and the other end (There are six on each flat side) are 2" above the concrete which means I have to fill 4" of something just to get level with the galvanized support bases/ (double 2x4 metal C-Channel). This is turning into a nightmare.
But thanks for the support. If anyone has any suggestions, I am all ears. I am at a stand still and I wanted to get the pool up by next week when school is out. Please, any advise?
Aranon:confused:

[hrsdennis]

Would it be possible to raise the entire area with some fill material? That would make leveling easier and you would have something to sink your side supports into.

I think I would look in that direction if it were me.

Dennis

[JJ in Tx]

Aranon,
I can't put a time on the cement setting up too many variables. If you feel you need to add a tad bit more cement or a light misting of water that would be alright, I just wouldnt recommend soaking it down. Most of the time with a cement stabilized sand you are compacting it so that is where your gaining your bearing strength. I think your form would work but I have to admit I do prefer Dennis raise the whole area suggestion. I think you would be happier in the long run if you where able to raise the area up to the height of the sidewalk and compact it well.
JJ

[haze_1956]

As I understand this, you are worried about sand running out from under the bottom rail

You should only need the cement/sand six to eight inches on each side of the rail

Possibly you could use something like the following :

http://i48.photobucket.com/albums/f223/slapics/poolbase.jpg

[Aranon]

Wow. you can draw the most awesome rocks. Great picture. Great Idea. I've started something like that. I am shooting a 1 1/2 x 1 1/2 angle down to the concrete with a Hilti Pop Gun and then cutting a 1 x4 scribed to follow the downward slope of the sidewalk to keep the top of the 1 x ? level. Then I am pouring about a 6" wide concrete to level with the board that will fit under the rail or so the rail sets on top of it sits level.

For the oval, I bought 10' lengths of the metal landscape edging from Home Depot with stakes and am going to level that and pour about a 6" wide strip level with the rest of the pool and then fill the interior with the 8 to 1 sand to Portland cement mixture and rake it smooth and then drag a board to make it perfectly level with the edges and the 2" buttress galvanized C-channels and hopefully this will smooth out everything level, straight and true so I may lay my 2" foam on top of all that. I bought the Gorilla Pad and not sure to put it on top of my foam or under it to protect from nut grass and roots. The Gorilla pad does not look very impressive. Looks like just plain ol heave white felt. I'm sure its something different but thats what it looks like with lots of folds and wrinkles that I am sure I will not be able to get out. That why I think I might want just the foam under the liner vs the Gorilla pad, because I don't think I could make it look as smooth.

I did not think about putting 6 mil plastic under the pool like your picture shows. I got some so I guess I could do that too.

Do you think what I have describe above will be OK. I am almost through with it.

Oh and I came up with a way to level my concrete blocks. I bought 1 foot pieces of 1/2" re-bar and drove the in the ground where my blocks would go and used the Transit to make them all the same height and the set my blocks to make sure they were all level and the were. I made sure the hole was about an inch deeper than I had to be and poured concrete in the hole about a 1/2 higher than the re-bar sticking out and set the concrete pads on the re-bar and let it settle on to the re-bar. Checked my level and now I have perfectly leveled concrete pads set in concrete with all the gaps filled up underneath them and the are move sturdy then when I just tried to dig and scrape level. I always had little gaps under them that I thought might settle out.

Thanks for all the advise. I will take pictures.

Aranon

[haze_1956]

You will have a 6 inch wide, solid concrete strip, under the perimeter rails and the 8-1 mix under the entire pool ? Just make sure the mix it is hard, or you might end up with very permanent footprints in the bottom of the pool

Frost might be a potential problem, but it likely could be, with any design.

Your plan seems more than adequate !

Best of luck.

[NWMNMom]

Just another alternative for the next person, we had to raise the entire area up 6" and so far it appears that it will work well - we used Class 5 fill (also called Class 13 in other areas - used for parking lots, roads - packs and dries HARD) Used a plate compactor x6 times over the area by quadrants - extended 24" out from pool frame with a very slight slope on the edge for drainage, framed by 6" high x 2" thick concrete edgers.

[Aranon]

Thanks all. This is more work than I thought. But its for my three boys so it's got to be worth it. I don't think foot prints would be much of a problem because the 2" foam board is going to go over it. Frost won't be much of a problem because we are just east of Dallas. Hardly ever freezes here at least enough to be much of a heave problem. I will let you know how it turns out. Seem to be so busy at work and the kids functions after work in evenings with schools ending I can't work on it as fast as I want to. Should have the perimeter poured and sand compacted this weekend. Maybe the liner up by Memorial Day. I hope.

Aranon:)