Pool Wall

The next few posts will cover specific choices that need to be made to decide which pool wall, which retaining method, which pump etc.  There are a thousand tiny choices that need to be made that are dependent on your design, size and type of Natural Pool you will build.  Will your pool be used by children; if so, you will want to ensure a fence is installed according to local ordinances.  Will you want a diving plank, slide, beach entrance, large boulders for entering pool, dock, zipline or climbing wall.  A rough outline should be made with primary objectives before any other choices are made.  Keep in mind that with every "upgrade" or addition cost to integrate, hire out and size up will incrementally increase your cost.

Another point to consider is, who will be using the pool and what depths of water do you prefer.  A lot pools have a good portion of the pool dedicated to 3-4' of water so people/kids can stand or play without having to tread water.  Consider shape and size of this area as you consider which type of wall to go with.

Pool Wall

If you have read David Butlers experience with building his NSP he laid his liner down without having any kind of support for his pool wall and after filling it, the earthen wall collapsed and he had to undo all of his work.  He told me he had to redo this portion twice to get it right.  I'll take his experience and learn the first time that we need a sturdy structure to hold back the ground and create a vertical or near vertical wall to separate swimming space with the regeneration area.

Cinder blocks

This is a great option if you are skilled with masonry working with concrete, re bar and creating solid structures.  The cost is a little higher than others, but this will give you flexibility in your design and ability to create whatever you want.  Here is a useful site to help determine how many cinder blocks you will need to complete your project.(you will obviously already need to know the approximate dimensions of you pool for this step)
http://www.cemexusa.com/ProductsServices/BlockCalculator.aspx

There are DIY methods for installing underwater lighting, skimmers right into the pool wall which aesthetically looks good.

Once I went through this process and figured it would take over 10 trips to the store and back with my trailer to get the correct amount along with $1800 not including the cement and rebar plus work, I decided to go a different route.  If this is the choice in wall you go with you might want to consider buying the plans and step by step process from a place like this to ensure it will hold up under the immense pressure and weight of the water.
http://www.homebuiltpools.com/plans/plans.htm

Cement/Gunite

These pools are highly durable versatile and provide the greatest amount of flexibility in terms of what you want out of your pool.  These are often "shot" out of the end of a hose where the mixture is equally mixed with water at the end or once it hits the wall and fills in a re bar netting as depicted here.

As you can see here, you can create extremely smooth corners and essentially go as deep as you want.  The cost for this option is the highest seeing you will need to hire this piece out which a lot of pool builders want to do the entire project.  The typical cost for a concrete pool excluding everything else like plumbing, coping, landscaping would start around $18k- and go upwards from there that is if you have a relatively small pool 15' X 20' with little customization.  Anything bigger would obviously increase your costs dramatically.

Gabion

Gabion walls are often used my state municipalities for erosion control.  It is a high gauge steel mesh basket that is filled with rocks tightly from bottom to top and help hold back earth while at the same time allowing passage of water.  This is an excellent option to act as a pool wall if your budget is tight and you have access to a large amount of 5" rocks this will create a relatively cheap wall.  You can buy 20' stock panels from stores like IFA/Cal Ranch for cheap and build your own as long as you secure them properly to each other with a high gauge wire.  As you fill them you need to stop every 2' or so and secure the front portion of the basket to the back with a high gauge stainless steel wire so you don't get a bulging in the middle of the basket.  Online you can find methods of building and filling these so I would recommend you go this route.  Dave Butler has recommended this type of wall for some in the UK when your budget is tight.

No wall

You can also just dig a hole, put a liner in or use bentonite clay which seals the bottom from water leaking out.  This is option is less than aesthetically pleasing, but cuts cost and makes the NSP usable for swimming, though it makes it harder to egress/ingress.

Wood wall

A final option I will discuss for your NSP wall is a wall made of wood.

You might think that wood kept under water for an extended period of time will eventually rot, but this is not the case when you use the correct type of wood.  White Oak, Yellow Cedar or Western Red Cedar, Port Orford Cedar are kinds of wood that will not rot in water.  Total Habitat is a US based company that builds NSP's and has great resources for those looking to build their own.  They also offer consultation if you're a bit leery about doing the entire thing on your own.

These walls shouldn't be more than 4' or so in height so they don't have too much pressure weight from rock and they should be built on a shelf and the middle portion of the pool can be deeper to allow diving etc.  These should be built in an octagonal or hexagonal shape so once you back fill the special gravel it will help lock the wooden frame into place.

This option is cheaper than most and easiest to install, but limits your flexibility in the shape of the swimming section.  One benefit of doing wood is you can build this offsite and in advanced and install once the liner has gone down.

 Here is an excellent video Total Habitat put together on this pool shown above.  It gives a great description of how the NSP works as well as shows the process they went into building it.

http://www.youtube.com/watch?v=D-qAQ5oYahM

Keep in mind that as you are planning your NSP, the wall needs to allow 4-6" of water to travel over the top from the swimming section into the regeneration planted area.

Pace yourself.  If you are seriously considering building a pool by yourself or without professional help, take all the time to consider every single piece of the pool, then rethink it and rethink.  You'll find that your ideas and plans will evolve and slowly come together once you know how skimmers work, UV Sterilizers, heaters, lava rocks, bacteria, pond liners, waterfalls, streams, aerating water, algae etc.  You need to know these concepts in and out and how they interact with one another.  Even knowing about these concepts, when you are actually in the dirt shovel after shovel your experience will triple what you actually learned and provide real tangible knowledge about how these work.   I have a boatload of Evernotes on each of these topics to help me understand and organize my thoughts and pictures/concepts.  Don't be overwhelmed.  One piece at a time.  Make notes on every topic. Check out the picture at the end of the post; this should give you ample excitement about what yours can be like!

To end this post, here is a great thought to consider.

Avoiding all opportunities for mistakes is avoiding all possibilities to progress.-Dallin H Oaks

Ping me if you have comments or questions about walls/your project.