Fiberglass Pool Retaining Wall/Locking Collar


Gold Supporter
Aug 8, 2020
Falls Church, VA
TFP Members, first a big thank you for all the assistance in preparation for a IG (partial) fiberglass pool install, the advice has saved me time and frustration. We were notified that we are on the schedule to start installation on Monday (26 APR) and I wanted to get a few thoughts before we are in the thick of it. Primarily it has to do with a retaining wall and the locking collar.

Our pool will be installed on a slight slope (about 18 inches of fall over the length of the pool), we considered doing a level install and putting a retaining wall along the perimeter of the yard/fence, but then our GC mentioned doing a partial inground install. We really liked some of the images that we saw and have pretty much decided to go that direction for a few reasons (mostly aesthetics).

So, based on a partial inground install with approximately 21 inches of exposure (maximum) that tapers down to approximately 8 inches of exposure I had the following questions and was hoping some of the experts here could weigh in. 2 of the sides of the pool will only have coping, the other 2 sides will have decking (IPE). The pool installation instructions recommend a 8 inch deep by 10 inch wide locking collar (to meet manufacturers specs and warranty).

Additional info - PB does not do concrete, hence my bringing my GC into the mix (and he will be doing our deck work).

My GC mentioned a few options for the retaining wall, stacked stone (the wife & I aren't big fans of this), cinder block faced with some sort of tile, and poured concrete.

Here are my thoughts on each and I really would appreciate advice/recommendations (especially if we haven't thought of something).
- Stacked stone - last resort...
- Cider block - to meet the manufacturers specs, that means I will have exposure (coping) out to a minimum of 18 inches (10 inches for the locking collar, 8 inches for the cinder block), this non standard coping size (for what we want to use (Mongolian Black flagstone) drives some material cost up pretty quick. Another consideration is we need to get the facing (tile or stone) on the exposed cinder block sooner rather than later to not be an eyesore.
- Poured concrete - Big question here is can I just frame in the pool and overpour the locking collar...basically give myself 14 inches around the pool to accommodate the coping and make up the exposure with concrete? So instead of having a 10"x8" locking collar it could theoretically be 14" x 21" (at max exposure)? I do see a downside of all of the concrete if something went wrong and needed to be replaced, but there are some pros as well...

Essentially what I am asking is if I can pour one big locking collar to serve as both the locking collar and the retaining wall.

Thanks for any input and I look forward to the recommendations from the experts...
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TFP Expert
Bronze Supporter
In The Industry
Aug 10, 2017
Morris Cnty NJ
You can pour 1 shot deal and serve both purposes. Be aware that 99% of the time the concrete face will be rough as the only means of finishing is vibrating the mix as its installed.
Personally, not a fan of raised installs. In a concrete pool the structure is solid amd theres no worries, amd the masonry work cam be tied in well. Usually this scenario plays out with either a rocky dig where depth is an issue, or costs associated with leveling amd a retaining wall.
It doeant help that I'm OCD and like cohesiveness, having 2 types of coping would drive me nuts. Keep in mind access for cleaning the pool all the way around, amd if the raised decking portion is high you would need railings to code
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