N.Design Studio

Guide to Modern Koi Pond Construction

Basically there are three types of bases that are used by koi-keepers for this type of pond construction and all three will be described here.

Method 1.
The sketch above shows the general layout of the most popular type.
Reinforcing rods or 8ft x 4ft sheets of reinforcing are cut and fitted in place. This is then raised off the base by about three inches.
A six inch deep layer of concrete is then poured into the space and levelled out.
When the concrete has had time to cure then you can start building the walls. At his stage they can be built up to say five or six blocks high, or higher if you wish.
This is a good time to back fill between the wall and the excavation with concrete.
At this stage you should also put in place the bottom drains and all the associated pipe work as described earlier.
When this is all completed then the steel reinforcing should be put in place for the second layer in the same way that you did for the first.
The second layer of concrete can now be poured.

Method 2.
The sketch above fig 10 shows the general layout where only one base is laid.
The depth of the bottom drains are six inches, and the pipes are four inches diameter so to ensure that there is sufficient strength in the concrete base in way of these items a trench is dug underneath them.
At this stage you should also put in place the bottom drains and all the associated pipe work as described earlier. To support them in the trenches then cement should be placed at certain intervals, and the pipes bedded into it.
Reinforcing rods or 8ft x 4ft sheets of reinforcing are cut and fitted in place. This is then raised off the base by about three inches.
Six inches of concrete should then be poured in and levelled off.
When the concrete has had time to cure then you can start building the walls.

NOTE. With this type of construction the depth of concrete is often more than six inches. If you are using nine inches then you should consider using two layers of reinforcing steel.

Method 3.
With this method as shown above in fig 11 the hole is excavated as normal, but then a trench is dug out for the foundations for the walls. This trench should be a minimum of 3inches wider than the wall on each side. So, for a 9" wall the trench must be at least 15" wide, and is usually quite a bit more. The depth of the trench should be from 9 to 12 inches.
When this is dug out then pegs should be put in to show the correct level and the concrete is poured in.
When the concrete has had time to cure then you can start building the walls.
As with method 2 the depth of the bottom drains are six inches, and the pipes are four inches diameter so to ensure that there is sufficient strength in the concrete base in way of these items a trench is dug underneath them.
At this stage you should also put in place the bottom drains and all the associated pipe work as described earlier. To support them in the trenches then cement should be placed at certain intervals, and the pipes bedded into it.
Reinforcing rods or 8ft x 4ft sheets of reinforcing are cut and fitted in place. This is then raised off the base by about three inches.
Six inches of concrete should then be poured in and levelled off.

NOTE. This method is only briefly described here. You should only attempt this if you have knowledge of the building trade, or someone who can advise you.