When all the work on the previous pages are completed then you are ready to start rendering the surface of the walls, base, etc. Although the blockwork is fairly easy to do yourself if you have the time most members find that plastering or rendering of the walls is one task that they prefer to get done by a professional.

Method 1.
The rendering is done with two coats. The first is applied directly to the blockwork, and when it is completed then the surface is roughed up with a trowel so that the top coat will adhere to it easily. The photo below shows the pond at this stage, and ready for the second coat to be applied. The render consists of the normal mortar mix of three parts sand to one part cement.

When the second coat of render has been completed then you will have a good smooth finish, and this should be carefully checked.
You must now decide what final finish to use on the pond surface.

One way is to use three coats of G4 pond sealer and following the maker's instructions very carefully.
This process is expensive, but proved over the years to work well.

Another product now on the market is P1. This is a too pack product, is easy to apply and is water based. It is available in clear, dark green, and black and can be purchased from East Riding Koi.

Another product is Koi-kote from Aquakote.

There have been good reports for both these products but I have not seen them in use in this area as most ponds are fibreglassed.

Method 2.
The method recommended by Rein Ltd the makers of fibromix is to use a thin (5mm) single coating of fibre reinforced cement. There recommendations are as follows: - The sand and cement are batched by volume using two parts of building sand to one part cement.
Fibres are added at between 25 and 30 grms per kg of cement used.
For simplicity, they recommend using a two gallon (9 litre) bucket. For each bucketful of cement, add at least 250 grms of fibres. (Do not consolidate the cement, leave as poured). A suitable mix for a small mixer would consist of 4 buckets of sand, 2 buckets of cement, with at least 500 grms of fibres.
The sand, cement, and water are first thoroughly mixed, then the fibres are slowly added with additional water as necessary. Thorough mixing, to uniformly distribute the fibres throughout the mix, is essential. Rein fibres are not liable to damage by extended mixing.
Only sufficient water should be added to give the desired degree of workability - excessive water is deleterious and should be avoided. The quantity mixed per batch should be based on the amount which can be used within about 45 minutes of mixing. Unquote.

The final surface of the render should not be too smooth and most professionals use a sponge in circular movements. This allows the G4 or other type of coating to adhere more easily to the surface.
Fibromix should be used even when the pond is going to be fibreglassed.

We will now look at the alternative of fibreglassing the pond.

See also Questions & Answers for Render & Fibromix.