Pool Blocks / Support Level - Adjusting (micro adjustments)

[archjeb]

Hi Folks,

I had to replace my old AGP that I installed several years ago because of rusting supports. Now that I have the new pool, I'm getting everything ready.
These are the old blocks I originally installed 5 years ago - so I'm hoping that when I lay out the new rail and supports, they'll all fall into the same location since its the same size pool. Will confirm when I take the rail and parts out of the box.

When I used a laser level, here are the differences from level for each block. 0" is of course the level reference. -" is under-height and +" is of course too high.
Some of these I'm being a little OCD on, like the 1/16" difference. But the ones that are way off (-5/8" & -1/2") those I'll probably pull up and use some cement bedding mix to raise the height?
Question on the -1/4" ones...has anyone tried using a latex thinset and skim coat the blocks to raise it? Thinset is usually pretty stable in < 1/2" thickness.





thanks,

-J

 

[Texas Splash]

Question on the -1/4" ones...has anyone tried using a latex thinset and skim coat the blocks to raise it?

I don't recall seeing any posts of such use, but we can search the AGP forum to see. Regardless, you are certainly on-point with that leveling. That should be one of the most level pools out there.

 

[CT-Steven]

As far as I know Latex thinset typically is used in tiling and has a working strength of 15lbs/Ft. Maybe there is a different product I am unaware of?

 

[archjeb]

As far as I know Latex thinset typically is used in tiling and has a working strength of 15lbs/Ft. Maybe there is a different product I am unaware of?

I thought modified thinset had a little more working/compressive strength than that. Its the shear strength that is not great, but I would think with the concrete block and the bottom rail plate on this...we're really talking compressive strength that we'd be concerned about.
Does the post actually have that much weight on it? Most of the force is downward on the floor of the pool and another vector of force on the pool wall pushing out. The weight of the post is probably only the distributed weight of the metal wall, liner pulling down, etc. Its maybe 300-400 pounds if I was to guess. Again, only talking downward force on the post itself.

ok, instead of Modified Thinset, I can use a vinyl concrete mix. It has a compressive strength of over 3,000 PSI in 7 days cure time.

Either case, has anyone tried this for a 1/4" lift? Seems plausible to fine-tune the height in such a small increment.

-J

 

[phonedave]

I thought modified thinset had a little more working/compressive strength than that. Its the shear strength that is not great, but I would think with the concrete block and the bottom rail plate on this...we're really talking compressive strength that we'd be concerned about.
Does the post actually have that much weight on it? Most of the force is downward on the floor of the pool and another vector of force on the pool wall pushing out. The weight of the post is probably only the distributed weight of the metal wall, liner pulling down, etc. Its maybe 300-400 pounds if I was to guess. Again, only talking downward force on the post itself.

ok, instead of Modified Thinset, I can use a vinyl concrete mix. It has a compressive strength of over 3,000 PSI in 7 days cure time.

Either case, has anyone tried this for a 1/4" lift? Seems plausible to fine-tune the height in such a small increment.

-J

Off the top of my head, I think it would work. I would use a bonding agent on the concrete block.

 

[archjeb]

The more I think about it; I think I'm going to go with the Vinyl Concrete, since its already has additives such as bonding agents already in the mix. It has compressive strength to 5,000 PSI after a month...and 3,000 in 7 days of cure time. I don't see how this can't work on the blocks to give myself a 1/4" lift.

Pulling out the blocks and adding a Polymeric Sand mix is an option, but for 1/4" I think its more disruptive to move anything around that has been in the ground like these blocks for 4 years. They've already compressed to where they are...they are not settling anymore than what they are. Pulling them out and dealing with disturbing the base will probably create more problems than what it will solve. I'll increase base with Polymeric Sand mix just on the 2 that are significantly lower...but for the -1/4" ones, I'm leaning towards the skim coat of Vinyl Concrete.

Kind of thinking out loud here...and bouncing the idea off the forum

 

[phonedave]

The more I think about it; I think I'm going to go with the Vinyl Concrete, since its already has additives such as bonding agents already in the mix. It has compressive strength to 5,000 PSI after a month...and 3,000 in 7 days of cure time. I don't see how this can't work on the blocks to give myself a 1/4" lift.

Pulling out the blocks and adding a Polymeric Sand mix is an option, but for 1/4" I think its more disruptive to move anything around that has been in the ground like these blocks for 4 years. They've already compressed to where they are...they are not settling anymore than what they are. Pulling them out and dealing with disturbing the base will probably create more problems than what it will solve. I'll increase base with Polymeric Sand mix just on the 2 that are significantly lower...but for the -1/4" ones, I'm leaning towards the skim coat of Vinyl Concrete.

Kind of thinking out loud here...and bouncing the idea off the forum

That was actually my thought as well. I wasn't thinking polymeric sand, just dry pack mortar. Kind of like making a shower pan old school. But as you said, pulling out the blocks is going to cause more disruption than it is worth.

Of course if you want to go really pro and dial in the pool you can go this route.

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[archjeb]

ok. So I thought I'd post an update here.

I went ahead and did a test on a few blocks that I removed. I wanted to confirm the bond of the vinyl concrete and to confirm whether it is a as strong or stronger than the actual block material.


First, I cleaned off all the tops of the blocks and coated them with a bonding agent.


Next, mixed up some Vinyl Concrete patch material. This stuff I've used for concrete repairs in the past and it works amazingly well, not only for bonding strength, but the compressive strength and additives make this a great repair mix.



I then did a 3/8" skim coat over the top to build up my paver height.
After a one week cure, this is what it looked like.



Now using a small sledgehammer, lets see how the bond is:




Trying to chip the Vinyl concrete off and near impossible. The Bond was PERFECT. The base material broke before the patch material did. So I'd say this will hold up no problem whatsoever for doing a micro-adjustment on these paver bricks.

I have only a handful of bricks that I need to do this on, but its quick and I have the confidence that this will hold up.

-J

 

[archjeb]

Month and a half later...and still looking great.
All posts were laser level set at 1/8" tolerance. Using the Concrete Patch worked great!

One thing I did not mention in my previous post; one of the blocks I needed to go a little higher to make up the height. I threw in a little bit of fiberglass flakes I had from another concrete project to add some additional strength. But the other blocks that were only a 1/4" low, I didn't worry about that as the Vinyl concrete patch has more than enough strength with its additives.

Now its time to finish the landscaping around the rest of the pool