How an Above Ground Pool Works

Above ground swimming pools vary slightly from model to model, but you will find that most manufacturers use the same general pool structure.


The wall is most typically made of galvanized steel. For round and oval pools, the wall is usually all one piece. The wall is corrugated for strength and then coated in vinyl and/or a number of other coatings to help protect it and give it a more attractive appearance. Usually, the more layers there are over the steel; the longer the wall can last.

The strength and durability of the wall defines the integrity of the pool structure. It must safely contain up to 200,000 pounds of water weight for the life of the pool.

The steel walls are shipped in coiled rolls, usually tightly bound and boxed in cardboard. Walls should be stood up on end until they are installed.

Above Ground Swimming Pools


The frame of an above ground pool secures the wall in place and provides much of the strength for the pool. It is important for the frame to be strong and able to withstand exposure to the elements, so they are generally made of coated steel, extruded aluminum, or resin.

Top Rails

Top rails form the top ledge of the swimming pool. Ranging up to 12" in width, the rails connect between each post (upright). You want these to be sturdy and tough. However, top rails are never designed to be sat on, stood on, or walked on.

Top Track

Sometimes called a stabilizer bar, the top track rests over the top of the wall, but beneath the top rails. The top track interlocks from top plate to top plate, helps to keep the top of the wall straight, and helps to keep the pool liner securely in place.

Base Track

The base track stretches from base plate to base plate between the uprights of the swimming pool and forms the bottom rim of the pool structure. During installation, this track has a groove into which the wall of the swimming pool is rolled.


The uprights, or posts provide support for the wall and top frame of the pool. Uprights can range up to 12" wide depending on the pool model and the material they are made of.

Top plates

You will find a top plate attached to the top of each upright. They provide connection points for the top track and top rails that span between each post.

Base plates

The base plates sit beneath each upright, providing a connection point for the base track and the upright itself.

Pool Top Track

Top Caps

Usually made of resin or other form of plastic, the top cap covers the top plate and help to give the pool a more finished, attractive look.


Some pools have plastic or resin boots at the bottom of each upright that, like top caps, cover up the base plate and are mainly aesthetic.

Pool Top Cap Covers

Vinyl Liner

The inside surface of the swimming pool is covered by a vinyl liner that contains the water within the structure. Liners are designed to fit specific sized pools.

As your pool ages, the liner may eventually need to be replaced. Patch kits can be used to prolong the life of the liner. Typically, you can expect a liner to last five to ten years.

Swimming Pool Vinyl Liner


You will find the skimmer attached near the top of your pool, about three quarters of the way up the wall. It is the opening that you see from inside the pool, right at the waterline, where the water is taken into the filter system. A skimmer's job is to pre-filter the water of larger debris before it gets to the filter, as well as help to keep the water clear of floating debris.

Most pool skimmers have a flap (called a weir) that helps to keep any floating matter trapped inside, and also regulates the amount of water that it processes at any given time. In the well of the skimmer you'll find a basket where leaves, bugs, and other debris can collect. The baskets can easily be removed from outside the pool and its contents emptied. Doing this regularly will ensure consistent water flow to your filter system.

For many pools, skimmers also provide a connection point for vacuum systems. When you want to sweep the pool, a specially designed vac hose is connected through the skimmer using a vacuum plate. When the pump is turned on, the suction will now power your pool vac.

Pump and Filter System

Filter systems vary depending on the size of the pool and the type of filter media used within them. They should sit near the pool, where they are connected to the skimmer and the return port through flexible hoses. The pool water is pulled in through the skimmer, processed through the filter, and then returned back to the pool through the return port.