Cinderblock pool walls?

[Nancy]

I saw a DIY website for building a swimming pool (you can find it yourself if you google swimming pools and cinderblock).

He claims that...

"The pool wall is fabricated out of standard 8" X 8" X 16" cinder blocks as shown. The first course of block is set into a concrete footing and the remaining blocks are stacked, not mortared, 5, 6 or 7 blocks high and filled with rebar and concrete. The pool bottom can be either compacted sand or a more professional perlite and concrete mix. A custom vinyl pool liner, ordered to your exact pool dimensions, attaches to the top of the pool via a track and is cushioned from the concrete block with packing foam. "

We're thinking about building a pool and as you guys all sound like you know your pools, can you answer these questions for us?

Is cinderblock commonly used in the building process for swimming pools?

From an engineering stand point, would this work? Would it be safe?

Thanks kindly for any info you can give us!

[Guest]

I'm waiting patiently.

[nota]

my pool is block but no liner solid concrete bottom and filled block walls
the large 38x18 poolwas built in 1955 and they just donot build them like that any more do to costs
we are in miami

[Nancy]

Thanks Nota
I've done a little research myself and been told that if it's in ground and back-filled with a continuous pour for the floor, it should be fine.
We're not going to put in a liner either, just going to plaster it with a white plaster.

[Guest]

plan on the plaster cracking in a step pattern that follows the block in about 2 years even if chicken wire and a brown coat are applied. Cinder block pools were not meant to be plastered.

[Nancy]

Pool User
Is there that much difference between plastering over poured cement and cement cinderblocks? What causes the cracking?

Nota, have you had any problems with the plaster cracking?

[lunitcfringe]

of course you can build a pool that way-its how it was done decades ago, just like most basements walls used to be cinderblock and most our poured concrete nowadays

sound like you shouled get a few cases of beer and invite your friends over for a pool building party-you can knock it out on a saturday

post pictures when youre done!

[dmay85]

So, if I understand you all correctly, cinder block pools are old school but reliable, and notably cheaper that nearly any other in ground option. I am thinking of doing this myslef next year...hire a guy to dig the hole, run the electric, and the rest myself. Is this an example of the industry making something more complicated than it has to be so us mere mortals won't attempt it without all their overpaid help?

[Larry]

solid concrete bottom and filled block walls

I think this is the key. Unfilled cinderblock will result in cracking over time and may not provide the absolute durability/ rigidity a pool requires.

[funinthesun]

i am also attemptimg to do an inground pool with blocks this summer. it is surely a reliable way to construct a pool. i am still in the research steps myself, but i have some things to think about. one being your plumbing and electrical. drilling through filled blocks and rebar is a nightmare, so it is crucial i think to get all your plumbing and fixtures in before you fill the blocks. another thing is your backfill process. to relieve stress on your walls it may be a good idea to have your pool ready for water prior to backfilling the dirt. this gives you an opportunity to test all your plumbing and electrical before it is covered up. also you are able to fill the pool as you fill in the dirt allowing an even pressure to both sides of your walls. this will relieve stress on the walls. as i go further in my project i will update my progress. best of luck in your projects

[40 year old pool]

I am in the midst of springtime opening a cinder-block pool built by my father and a couple of friends - 40 years ago. Don't let anyone tell you it can't be done or that it's doomed to failure. However "lunaticfringe" posted that you should be able to knock it off in a weekend - well that's just fallacious, I was only about 5 when they built it but I distinctly remember it being a lot of work - also one of the guys was experienced with concrete which certainly helped.

My dad told me all the engineering was provided by the local block manufacturer - perhaps that's a good source for info. They used the filled block & rebar method for the walls, sealed with a plaster layer, and then coated with a finishing layer. The floor was formed with a steel mesh and rebar then filled with poured concrete. All deck surface options are available - he used ledgerock flagstone ( hey it was the '60s ), standard plumbing and standard pool equipment.

I live in a northern climate so the pool is subjected to annual freeze/thaw and requires normal winter shutdown procedures for pump and filter. Water level is lowered to below the skimmer. Springtime maintenance normally consists of fully draining to clean out leaves and debris ( pool is oddly shaped and doesn't have a cover ), cleaning with a pressure washer, chipping out any loose bits ( around the iceline gets a little rough ), then resurfacing with a waterproof masonry coating. The coating I've used is a dry powder that's mixed with water (I also recommend using the available acrylic fortifier) to a soupy consistency that is applied with a whitewash brush. Colours are premixed white or grey but tinting is available for different colours. I use Quikrete brand because that's what they sell at the local building supply - I imagine there's other manufacturers as well.

This year the surface is better than ever with the exception of two small areas ( total about 2 sq ft ) that will require a little extra maintenance. Also in the last couple of years I have had some minor repairs requiring filling with hydraulic cement, applied by hand and allowed to dry thoroughly, before applying surface coating.

So, you can see there is some work involved but there are numerous positives as well - the major ones being:
- good technique for DIY
- unique designs possible (ours is Y-shaped with an extra long shallow end - great for little kids)
- no vinyl liner ( how many liners would we have used in 40 years, at least 2 or 3 I'd guess, and they go for $3,000 - $4,000 a pop around here ); you can let your dog swim ; the pool area doesn't have that plastic smell ; it seems easier to keep the water clean with less chemical use
- no plastic coping
- you can make it a different colour every year. I like white as it makes the water look crystal clear and clean. My dad most often did medium green walls and white floor, that looked good too.
- I don't know the current cost comparison but I imagine the upfront costs are still lower
- I saw somewhere that the design life of this method is 20 years - but this pool's 40 year track record in a northern climate speaks for itself - it's durable !!

I'm not saying this method is for everyone but it might be right for you - good luck !!

[Block Pool]

40 Year Old Pool,
We moved into a house where the previous owners did just as your dad did. Ours is still in great shape too!

Last year we had a hole in the liner (and didnt know it then). We thought there was a leak in the main drain, thanks to a local pool company. We removed our liner with no chance of putting it back in. When we removed the liner, we have found that there are two or three blocks that have moved away from the wall.

Have you ever had to "push" a block or two back in place? They are out approx 1-1/2 inches. How can you fix this?

Also, what do you use to "paint the pool"? Im getting tired of the expensive liners every five years or so. Have to buy one this year since we destroyed ours last year.

Thanks!!

[ive found what u need!]

go to sanitred.com its perfect!

[echo512]

Sorry to post additional question, but as far as using cinder block walls, etc., I'm assuming all of this needs to go through a structural engineer for stamping, and submittal to the city for approval before digging/starting?

Is there any detail to the correct mixture needed for the concrete:
1) poured as a foundation
2) poured into the cinder blocks

Also, what size rebar, and number per hole in the blocks?

How to make curves in the design?

Any other good sites with this DIY in mind?

Thanks!

[QUESTWORLD]

Funinthesun,
have you gotten far with building your cinderblock pool? I will be starting mine here in the next month poured floor and setting the first row in with that and rebar. Stack and fill after that for the wall. Cost that i have estimated so far are way below any other option esp with doing most of the work myself.