Waterproofing Fish Ponds

Waterproofing Fish Ponds

A concrete/brick fish pond adds aesthetic appeal to the garden landscape, by providing a habitat for fish of most varieties, and associated plant life. However, concrete is a porous material and can eventually leach lime and other chemicals into your pond, unless the pond is correctly tanked with a flexible, non toxic, fish friendly waterproofing membrane system.

Ensure correct application, by starting with clean concrete, free of dust, debris or living vegetative materials adhering to the surface.

This method dispenses with the cost and additional labour of fundamental concrete waterproofing by simply applying a waterproofing coating on the inner surfaces of the pond after the shell is constructed, and it works with either insitupoured shells or with brick/block construction. Avoid applying membranes to ‘green’ concrete until it has properly cured. You should plan on waiting at least 28 days for the concrete to hydrate and cure. This can be a frustrating task because you’ve been waiting for either the pond or the repair to be completed, and now you must add almost an entire month to the wait.

Concrete takes time to hydrate, and you don’t want to lock in any residual moisture. Cracking could occur if this process is hurried. The only indisputable method to speed up the process, is to add an accelerator to the concrete when it is mixed. Then this process is cut down to 7 days. There are several types of membrane systems you could use to effectively tank a pond, however, we recommend using 2 x coats of a water based 2-part epoxy, followed by 3 coats of a fish friendly liquid membrane.

The more elasticized the membrane is, the better the chance of bridging small cracks and even tolerate a small amounts of movement, so they can be very forgiving and are often used to waterproof leaks in existing concrete ponds. The key to these applications is suitable surface preparation, so the manufacturer’s recommendations must be strictly adhered to. The more stable the concrete base, the better the coating will perform.

Watch the weather forecast before you begin your pond waterproofing project. Make certain you will have enough rain-free days for cleaning, waterproofing and curing. Pond membranes generally take 10 days to cure, prior to filling with water.