If your concerned about something a pool builder said to you or just genuinely curious about the pool in your backyard, you may wonder how thick are gunite pool walls? Like many answers to questions about pools, it depends.
How Thick Are Gunite Pool Walls?
Factors that affect your pool wall thickness include what type of steel you use, what part of the country you reside in, and many more things. We will explain the variables that affect the thickness of gunite pool walls and the most common density range.
There is one quick note before explain how thick gunite walls in your pool are. Gunite refers to a concrete placement method called “dry-mix shotcrete”. We often refer to pools as gunite pools, but in reality, they are concrete pools once the concrete is placed by the dry-mix shotcrete process.
Thickest Part Of Pool Walls: Bond Beam
The top of each pool wall will be the thickest part. This part is what pool builders call the “bond beam” or just “beam”. The wall widens at the top of the pool primarily to achieve the thickness of the coping stone. The coping stone is the material to be placed upon the top of the pool.
Average Thickness Of Bond Beam
For example, imagine you’re using 14” bluestone coping and you want a 1” overhang on the inside of the pool. Subtract 1 1/2” for the overhang and the tile thickness. Then, you’re left with a 12 1/2” gunite beam dimension. Generally the bond beam is between 10” and 16” but can vary widely depending on the design of the pool finishes.
The bond beam and the walls and floor below are made up of concrete and rebar. To determine the wall thickness we first must consider the basic requirements. There are standards for placement of rebar relative to the water side of the wall, as well as standards for the placement relative to the earth side of the pool wall.
One of the standards used by most pool engineers is ACI 318. Within this code, Table 220.127.116.11.1 shows the minimum spacing between the earth and the rebar as 3”, and the “weather” and the rebar as 1 1/2”.
Factors That Influence How Thick Are Gunite Pool Walls
There is not a “one size fits all” answer to asking how thick are gunite pool walls. Factors such as the steel type/thickness and where your pool will be located matter a lot. We will now explain the different rebar (steel) sizes we’ve used to build pools and the average thickness of a pool wall in various parts of the country.
The most common size of rebar used in a pool is 1/2” or #4 rebar. Some pools will have larger diameter bars. If used, the pool wall thickness needs to be changed to accommodate them. Since the rebar runs in two directions in a pool wall, if you’re using 1/2” rebar tied together in opposing directions, the rebar dimension will be 1” thick. Add the 3” to the earth and the 1 1/2” to weather, and you have 5 1/2” minimum wall thickness. However, most pool engineers will specify a minimum wall thickness of 6”. This is done to give the construction crews a little flexibility.
Although, there are more calculations that go into determining a pool wall dimension than the rebar spacing to earth. It’s not uncommon for the concrete thickness to be specified as 8” or 10”. In fact, in parts of the country like Austin, TX most pools built have 10” walls and floors minimum. Whereas in the northeast a 6” wall and floor is common. This discrepancy is why a good structural engineer is paramount to a successful pool build. The differing demands on a structure must be taken into consideration before building a pool. There is no substitute for engineering, especially when it comes to pool construction.