Support under side rails

[DennisP]

This side conversation has been split off of this topic. JasonLion

Ok, I really don't get something here...why are you putting foam board under the bottom support rails? Foam board will not support the weight of the wall on a rail. You should be putting the foam on the inside of the bottom rails, not under them. Basically a big circle the size of the inside area of the bottom rails.

A permanent above ground pool is not anything like an intex pool. People do this stuff with intex pools because there is no support outside of the footings. The bottom rails support the wall just as much as the bottom plates. If you look at Casey's install she has pavers even under the middle area of the bottom rails. That is considered overkill, but by far only helps support them as much as possible, so there is no issue doing that, especially if you had to fill the area and the fill was not compacted or was compacted with sandy soil, then you most certainly have to do what Casey did.

My point is foam board is not able to support the rails. You really have to sink the pavers to ground level and put the foam board on the inside of the bottom rails. I am doing just that on my install, just that I will have a base of limestone so I don't need pavers, but I am going with 1.5" thick foam board and that will be a giant circle inside the bottom rails.

Even though it could be argued that the bases on the pavers will take all the weight, but it also creates singular points of stress on the wall as well. The rails having less "solid" support doesn't mean it doesn't get spread over a wider area.

I removed an all-resin pool that basically had a couple of lower rails broken because they didn't have enough support under them and you could tell the wall was buckled between where it happened on the support bases that had pavers.

- - - Updated - - -

Just wanted to say you are definitely doing everything else right and by the numbers though... Good work so far...

 

[phonedave]

Re: Northeast Ohio AG Pool Install/Build

Ok, I really don't get something here...why are you putting foam board under the bottom support rails? Foam board will not support the weight of the wall on a rail. You should be putting the foam on the inside of the bottom rails, not under them. Basically a big circle the size of the inside area of the bottom rails.

A permanent above ground pool is not anything like an intex pool. People do this stuff with intex pools because there is no support outside of the footings. The bottom rails support the wall just as much as the bottom plates. If you look at Casey's install she has pavers even under the middle area of the bottom rails. That is considered overkill, but by far only helps support them as much as possible, so there is no issue doing that, especially if you had to fill the area and the fill was not compacted or was compacted with sandy soil, then you most certainly have to do what Casey did.

My point is foam board is not able to support the rails. You really have to sink the pavers to ground level and put the foam board on the inside of the bottom rails. I am doing just that on my install, just that I will have a base of limestone so I don't need pavers, but I am going with 1.5" thick foam board and that will be a giant circle inside the bottom rails.

Even though it could be argued that the bases on the pavers will take all the weight, but it also creates singular points of stress on the wall as well. The rails having less "solid" support doesn't mean it doesn't get spread over a wider area.

I removed an all-resin pool that basically had a couple of lower rails broken because they didn't have enough support under them and you could tell the wall was buckled between where it happened on the support bases that had pavers.

- - - Updated - - -

Just wanted to say you are definitely doing everything else right and by the numbers though... Good work so far...

I would put the rail on soild ground as well.

I will go you one better. I was talking to my neighbor the other night about my pool - he was here when the original owner of my house installed it. Mine is not installed correctly (Ill be fixing that next season). I asked my neighbor if he used paito blocks under his posts (mine are on chunks of slate). He said no, he dug a trench, and poured a level concrete ring to put his pool on. Overkill maybe, but I am sure that pool is not going anywhere.

-dave

 

[Casey]

Re: Northeast Ohio AG Pool Install/Build

I've seen it done here with the ring last year Dave.

 

[Augie56]

Re: Northeast Ohio AG Pool Install/Build

Buy some extra pavers the same height as yours and slide them under the rail all the way around. Piece of mind. Those pavers should be about $1 a piece at Home Depot or Lowes. Plus it will look nice and consistent all the way around on the outside. I know...I just bought 70 of them for my install.

 

[DennisP]

Re: Northeast Ohio AG Pool Install/Build

I know this is an "enthusiast" website, but a lot of these topics are about general engineering principles that really need someone qualified to answer them.

To the OP, you may be *OK* installing it that way, but the fact remains you will never find anyone professionally that will ever use that method to install a pool. If you have sandy enough soil to worry about the rails not supporting the wall all the way around, then a professional will install pavers or a crushed aggregate ring around for the pool base (pouring concrete is extreme, but I have also heard of that one as well)...

Fact of the matter is that over time the foam will degrade, it will not support the weight of the pool and you will have degrading where the rails are sitting on the foam. If you really wanted to "hedge your bets" and go that route you are better off installing the bottom rails with a 1/4"-1/2" interference to the foam, so that it will pre-crush the foam as the pool goes up thus making sure it is "sealed" around the bottom rails.

The best bet is to not have the foam where the walls are.

 

[Casey]

Re: Northeast Ohio AG Pool Install/Build

Are you a pool builder Dennis? This forum is chalked full of advice from many posters, including myself who've been owners and DIY builders several times over. No one needs a degree to assemble an above ground pool and quite frankly, there is more than one way to skin a cat. These pools come with instructions and a lot of YouTube vids for those brave enough to embark on such a project. I suggest you take a chill pill and cool off with your structural engineering diatribe. This is a DIY forum and professional installs are also welcome.

 

[PPrince]

Re: Northeast Ohio AG Pool Install/Build

Dennis - I think your advise is good and would encourage anyone else considering a similar build to do it that way. At this point, I'll keep a close eye on things.

Dave - I can see the superior support a solid concrete foundation would provide and the idea intrigues me, but the cost has to be pretty high. Especially in areas where the ground freezes in winter. Plus when the pool comes down someday you've got this big concrete circle in the back yard to deal with. I suppose you could convert it to a bocce ball court or tell the grand kids it's a landing area for space aliens!! Lol

 

[JasonLion]

Re: Northeast Ohio AG Pool Install/Build

To the OP, you may be *OK* installing it that way, but the fact remains you will NEVER, EVER, EVER find anyone professionally that will ever use that method to install a pool. If you have sandy enough soil to worry about the rails not supporting the wall all the way around, then a professional will install pavers or a crushed aggregate ring around for the pool base (pouring concrete is extreme, but I have also heard of that one as well)...

{This portion WITHDRAWN}

There isn't any especially large weight pushing down on the bottom rails. Mostly the water is pushing the walls out horizontally (and also subjecting them to twisting and leaning forces). The bottom (and top) rails primary purpose is to help hold the walls in place against these horizontal forces.

 

[DennisP]

Casey, no, not a pro pool builder... But I am an engineer. And yes, it may be argued that a lot of this stuff isn't rocket-science, but that doesn't excuse dangerous advise at times. Again, sound judgement based on proper decision making is paramount. I found the proper answers from someone else "in the business" that I didn't want to bother since they are on vacation, but called me asking for some computer help, so I asked.

 

[DennisP]

JasonLion, I watched that whole video, primarily because I have ordered from InyoPools and would have been shocked if they recommended putting sand under the bottom rails. In the video linked they never mention putting sand under the wall rails. They talk about pavers, but nothing about sand outside of being inside the pool area, but not under the rails.

Point being, if a pro pool builder would put sand under a bottom rail, they are NOT a pro. No two ways about it. It is just flat out wrong to do, since it WILL wash away. No sense arguing that point.

You can look online and you will find pics of where the dirt washed out under a bottom rail and the wall buckles near the posts because of that. The whole point is you need a solid base all around the pool, with teh posts needing pavers and the rest needing a solid surface.

 

[JasonLion]

Agreed.

 

[phonedave]

Casey, no, not a pro pool builder... But I am an engineer. And yes, it may be argued that a lot of this stuff isn't rocket-science, but that doesn't excuse dangerous advise at times. Again, sound judgement based on proper decision making is paramount. I found the proper answers from someone else "in the business" that I didn't want to bother since they are on vacation, but called me asking for some computer help, so I asked.

There are some engineers on this site. Specifically some with an M.S. in construction engineering management and a concentration in soils/gound modification. Some who used to work as a field inspection engineer for an earthworks engineering company - inspecting foundations, earthern dams, ground water flow, and pile driving projects.

I agree, foam under the perimiter is NOT a good idea. You need a solid base. Solid does not mean sand, solid does not mean you packed down some earth with a tamper, concrete is overkill (but then I like overkill) - but there really is not THAT much weigh on the perimiter of the pool. There is a lot of ourwards force containing the big bag of water inside, but the bulk of that bag is sitting in the middle of the pool.

-dave

 

[phonedave]

Re: Northeast Ohio AG Pool Install/Build

Dennis - I think your advise is good and would encourage anyone else considering a similar build to do it that way. At this point, I'll keep a close eye on things.

Dave - I can see the superior support a solid concrete foundation would provide and the idea intrigues me, but the cost has to be pretty high. Especially in areas where the ground freezes in winter. Plus when the pool comes down someday you've got this big concrete circle in the back yard to deal with. I suppose you could convert it to a bocce ball court or tell the grand kids it's a landing area for space aliens!! Lol

I don't think you would need to do a complete circle of concrete, just a ring, sort of like a curb, for the perimiter to rest on. When you take down the pool, it becomes a teatherball court

-dave