Plumbing Assessment & Repairs

[JoyfulNoise]

I find it surprising that a fiberglass pool shell is built without the penetration points being mechanically stabilized by building up the material in those areas to a much thicker degree or providing some kind of compression flange with a very large diameter to compensate for the fact that a fiberglass shell looks essentially equivalent to an eggshell in terms of mechanical forces. Expecting the shell to handle any kind of moment-arm is ridiculous.

Pat, when you get to it, let’s see what you’re thinking about doing in terms of supporting those return lines? I’m sure there’s plenty of us here that will give you our highly qualified, completely bogus advice given our vast experience at complex engineering designs … I, for one, hold several “Facebook degrees” in science, engineering, mathematics, law, medicine, pharmacology, art-history, and Paleolithic mesoamerican gender-queer basket weaving … you can trust me …

(All statements above are purely satirical, any implied guarantee is null and void. All liability is strictly prohibited. Proceed at your own risk.)

 

[Jimrahbe]

What Matt says is all true... Just look at his hair...

Jim R.

 

[JoyfulNoise]

Maybe consider using some 2” Wye fittings with an additional 45° connector to make a smooth transitions rather than Tee’s with hard 90’s -

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Sweeps too at the flange -

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[JoyfulNoise]

I was thinking that you might want to add some cut up 2-1/2” PVC pipe as braces that butt up to the FG shell near the bottom manifold that will deliver water to those ports. If you brace the bottom of the pipes with an equivalent length of PVC that pushes against the shell, then there will be minimal moment arm and rotational force. PVC tees can be split in half to act as a crutch contacting the pipes and you can probable add a solid 2x6 wood board for them to push against the shell. Pressure treated wood won’t deteriorate when it’s buried. Between that and your long paver idea, there should be enough support.

I like the paver support idea but it still doesn’t stop any settling, it just spreads out the load. Adding braces that butt up to the pool wall will reduce rotation.

 

[Texas Splash]

Okay, just about done here with exception of filling-in the hole. Here's what I elected to do. For reference, I'll number the jets from left to right 1 thru 4. This post is the plumbing only before adding supports. If you're asking "Why the loops" for jets 1 and 4, well, 2"PVC doesn't have much flex to it. Ha. There was no way to work my way down one jet at a time, trying to get the PVC into a T fitting and return jet at the same time. I also wasn't comfortable trying to construct and glue an entire branch line of 4 jets at once and slapping it on (hopefully) before it dried. Instead, it made sense to make a center manifold then split a loop to each end jet. It worked well and I think will distribute water evenly to all jets.

 

[Texas Splash]

Here are a few pics with the support pavers. Since I leletec to bring the branch feed to the middle betweeh jets 2 & 3, this alleviated some weight stress (IMO) to all jets. A single paver in the middle under that elbow provides the main support in a great location.

Then you can see pavers shimmed in place on the loop ends at jets 1 & 4.

 

[Texas Splash]

In summary, if you compare the repair job to the original installation, it is MUCH more robust and solid. The original plumbing was split at the corner of the pool (T fittings) that takes water to two different branches of flow for the jets (bench side and end of pool). At that T fitting, they reduced from 2" to 1.5" at each of those return branch lines. Flex pipe was used which provided zero support. Lastly, the original return jets had a thin nut on the backside of the shell to hold the jet in place. The new CMP jets have a large rear housing that secures the jet to the wall and extends about 3-4 inches out for the PVC to slip into. MUCH more stable.

Once I had everything assembled and glued, there was next to no movement. The entire plumbing structure is very solid, but I elected to add some paver support just in case. I was not able to use a suspension method (i.e. hangers) for the plumbing because there was no good access points to the shell from below.

 

[Texas Splash]

Lastly, I used this time to apply fresh silicone to all of my exposed areas like the skimmer, LED fixtures, and the 2 return jets one the bench side. You know my chalky story, so try to ignore the crazy chalky discoloration.

 

[Texas Splash]

And just to add insult to injury, this is a pic of one of the two return jets on the bench side. What do you see? Yep, that line settled as well which is why you can see a gap at the bottom. I inspected the interior of the return line/fitting and (so far) it has not cracked like the other jet did at the end of the pool which started this whole project. If/when the day comes where I need to replace those final two jets, I'm confident it will be a piece of cake compared to the four I just did.

 

[JoyfulNoise]

When you have the FG pool installed, it looks like they did a sand backfill. Was there an option to do stone at all? Seems like the sand and clay combo has not been kind ...

 

[Texas Splash]

When you have the FG pool installed, it looks like they did a sand backfill. Was there an option to do stone at all? Seems like the sand and clay combo has not been kind

10 years ago it was all sand with no mention of any other backfill material. Honestly I didn't know any better back then. Last week I went to the showroom to pickup my CMP jets, and I showed them pics of how their install settled. I asked if they have changed their method, and sure enough now they use gravel. At least for the base and perhaps partially up the walls. They still like sand for some areas as it is easier to "pack" and stay where they want it.

 

[JoyfulNoise]

10 years ago it was all sand with no mention of any other backfill material. Honestly I didn't know any better back then. Last week I went to the showroom to pickup my CMP jets, and I showed them pics of how their install settled. I asked if they have changed their method, and sure enough now they use gravel. At least for the base and perhaps partially up the walls. They still like sand for some areas as it is easier to "pack" and stay where they want it.

Agreed. 10 years ago if I only knew then what I know now, my pool would be VASTLY different. I’m hoping to never have to build another pool but … you can never say never. At least if I did, I would be much better prepared and I’d probably O/B it myself.

 

[Dirk]

There was no way to work my way down one jet at a time, trying to get the PVC into a T fitting and return jet at the same time. I also wasn't comfortable trying to construct and glue an entire branch line of 4 jets at once and slapping it on (hopefully) before it dried. Instead,

Maybe that's why they used flex. Would have gotten them home earlier that day.