Building a Koi Pond
Types of Construction
In building a Koi pond there are several options you have for the type of construction. The three most common types and the ones I would recommend you stick with are concrete, liner-only and concrete block walls with a liner.
The concrete is clearly the most expensive option when building a Koi pond. A concrete pond is a serious investment for sure, given the more complex construction that is involved. They have to be strong enough to deal with ground movement from freezing temperatures in some locations as well as clay and sandy soils in other locations. Make sure you don’t underestimate the cost of materials – concrete and rebar. If you live in a cold climate remember the concrete will need to be at least 6 in. thick.
The three biggest advantages of the concrete Koi pond include its durability; it’s easily accented with marble, slate, tile or brick; and while expensive it is a one-time investment. Plus if you get tired of your Koi, turn the pond into a swimming pool. Seriously it would be that hard. Of course, if you’re tired of your pool, the opposite is true also.
Using a pond liner when building a Koi pond is a very popular option. It is also relatively economical. Liners are usually made of PVC and available in several thicknesses. You’ll need to have a liner that is at least 20 millimeters, single ply. This will last about 10 years. If you use a liner 32 millimeters thick they can last from 15 to 20 years.
If you can find it, butyl rubber liners are a terrific option. They are 30 millimeters thick, are not affected by sunlight. These can last 50 years or more. They are not very common outside of Europe and so can be hard to find.
Pond liners have several advantages. While it’s a bit of work to install, they are a lot faster and cheaper than concrete. They are usually in one piece which helps them not to leak, if installed correctly, without any folds where stagnant water can collect. If the liner does spring a leak it can be easily patched or a new liner can be installed on top.
An option that combines concrete and a liner is building a Koi pond that has concrete block walls with a PVC liner. This option does not have a concrete bottom to the pond and so is somewhat less expensive than a completely concrete pond.
The decision on the basic type of construction you are going to use is one of personal choice, unless there are some terrain issues that will dictate what has to be used. Think about your overall objectives for your Koi pond and how it fits in to your backyard or garden setting.
