IG vinyl pool renovation : cracked concrete deck

[John Rock]

Hi,

This year I'm planning to finally redo my IG pool that has badly cracked concrete deck. I have a few questions/concerns :

- The huge cracking/shifting most probably came from an unstable base. How can I make sure this never happens again? (concrete or helical pile footings?)
- Would the problem have happened anyways with another type of decking? (I live in Montreal, Canada)
- What is the optimal construction technique for a steel/vinyl pool and decking?
- Is concrete decking required under pavers anyways, to keep it all level?
- Any considerations when choosing the vinyl?
- My main drain seems usesless (poor suction); it goes back to the skimmer. Is this design obsolete now?
- When I bought the pool, one of two return valves was broke and couldn't be repaired without breaking the concrete, so I didn't repair. How could this be avoided this time? Pavers over returns?
- My pump and filter are currently lower than the decking level, under my home's wood deck. Is this good practice?

I basically want a bullet proof pool with a low total lifetime cost, and I'm not very good at maintenance (lack of time).

Thank you for your help!

 

[Divin Dave]

Hi John,
Three things in life are certain. Death, Taxes, and concrete will eventually crack.
Whole Books have been written about concrete, so there is no easy answer to the question. However, if you have enough money, then you have no worries! haha (said with tongue in cheek).

There are a lot of things that can be done to minimize the cracking and also control where the cracking occurs, such as having control and expansion joints. These should be properties of any concrete such as a deck, driveway, parking lot, road or whatever it is. And the control joints locations should be properly located. It does matter where they are put! Google "concrete control joints" and you will find all sorts of info about it.

In cold climates, you ultimately are best by getting footers or piers below the frost line. Another way is to excavate below the frost line and then fill with non compactible material such as gravel. If you dont get your deck support below the frost line, then nothing will prevent it from being heaved and cracking uncontrollably.

When the concrete eventually cracks and it eventually will, hopefull it will crack in the control joint, but if not, then the cracks need to be filled with flexible concrete crack filler asap. Otherwise, water will get in, freeze and make the crack much much worse. Sealing the concrete also helps extend the longeviety as well as the aesthecs of the deck and you will have to do it every couple of years.

If you install pavers, teh technique varies by regions. One way is to use sand, the other concrete. Concrete method same as above. If sand then the ground is dug down 4 to 6 inches and sand is put down, leveled and compacted several times until its perfect. However if the substrate is terribly unstable, then the same process of excavating and installing gravel and sand to level would be in order if you want it to last and last and last. You can get a geological survey of your property done to determine how stable (or not) the soil is. A geo-survey is the only way to really know what the best way to proceed is.

As for the main drain. Sounds like a typical installation. A better way to do it, would be run the main drain pipe directly to the equipment pad and install a valve so it can be turned on and off as needed. For that matter, a main drain is not a necessity at all. Many many pools are being built that do not have a main drain at all. My pool is one of them.

The best way to keep a return from being broke, is to install it properly to begin with and use quality materials. And in your case where it gets terribly cold in wintertime, winterize the pool properly. There is no good reason why an underground/ under-deck return should have to be dug up, if installed properly.

As for vinyl liner. Get one from a reputable company. There are lots of options, such as the pattern of it, how visible (or not) the seams are, the thickness of it. As with most anything, there are lots of opinions about if a 20, 28, 0r 30 mil liner is best. The honest answer will really depend on who and how is using the pool. Will dogs with claws be in it? Used by lots of kids? will you be turning flips at the end and kicking off the pool wall with your feet? All of these types of things would mean you would want a thicker liner. If its just you or a couple of you lounging around, a 20 mil liner would do fine. Determine who and how the pool is used and make a decision based on what the risks of the liner getting torn. AN EXCEPTIONAL NOTE: Water Chemistry is the most imporant lifespan improving element of a vinyl liner. Maintain the pool chemistry properly and the liner should last a long time.

Its not in the least unusual for your equipment to be lower than the waterline. As for it being under your porch, well for me it seems like that might be a tight spot. Personally, I like to have plenty of room to work on something if I need to, and do it without having to drag out a work light.

I hope some of this rambling helps,,

 

[John Rock]

Thanks for the reply Dave. Indeed, I did read that all concrete will crack, but in my case, the issue wasn't so much the crack, but the movement of the decking after. I didn't know caulking was necessary if the decking had no where to go, resting on a solid base. Does the way the "braces" are built around the walls have an impact? I see some builds using X bracing, producing a top support that seems like a way to support the decking. Also, any opinions on concrete copping, given that it WILL crack?

Thanks!