How to Fibreglass a Pond

Fish pond

Do you want to line your pond with fibreglass? If you’re planning to fibreglass a pond, then the first thing that you should consider is the weather. If the weather conditions are damp, or it looks like a storm is on the way, then it’s not the ideal time to fibreglass your pond.

You could choose to get a tarpaulin tent built over the pond to keep the area completely dry. The rate of the fibreglass pond’s cure could also be affected by weather that is over 25°C. Note also that there are resins that may not work properly in temperatures lower than 10°C.

Also know that fibreglass also doesn’t adhere to products made of plastic. So if there is anything made of plastic in the pond, such as the guttering, then a seal may need to be created.

What do you need to fibreglass your pond?

This is everything that’s needed to fibreglass a pond:

  • A strand mat, chopped, of 450gsm
  • Flow coat
  • Polyester resin
  • Catalyst syringe and dispenser
  • Catalyst
  • Acetone, either a roller cleaner or a brush
  • Brushes that can be thrown away
  • Mixing buckets of at least 2.5 ltr
  • Sticks for mixing
  • Storage bucket of around 1.6 ltr
  • Metal rollers
  • Paint rollers
  • Removing cream for resin
  • Gloves made of rubber

Before adding fibreglass to the pond, the surface will first need to be prepared. Before the lamination process begins, consider lightly rendering the pond. If you want to use fibreglass to matte your pond, then you’ll need to avoid sharp and right-angled corners.

The surface that will be created, using sand or cement, is what will then be replicated when fibreglass and resin are used. This is why it’s important to sand sharp areas of the pond. The result of the sanding process is a smooth finish all across the pond.

Before you can add fibreglass to your pond, the surface that’s rendered must be both dry as well as clean.

Once the resin or the gel coat has been mixed, you won’t be able to take a break. This is because the resin or gel coat could end up curing while you’re on your break.

What are the steps involved in adding fibreglass to a pond?

There are several steps involved in adding fibreglass to a pond. These include:

·      Step One

The first step involves cutting the fibreglass into squares of 50cm each, so they can be used more easily. A Stanley knife or scissors are usually used for this step.

·      Step Two

Next, the resin will need to be mixed with the catalyst. If you’re using a catalyst syringe or dispenser, then add around 10cc of the catalyst for every 1L of the resin. If the weather is cold, then increase the amount of catalyst being used to 25cc. The result is a hardening time of 45 minutes.

Using the correct ratio of catalyst to resin is important. No less than 10cc of catalyst and no more than 30cc of catalyst should be used, per 1L of resin. Going above or below this ratio could end up affecting the curing time.

·      Step Three

Next, it’s time to make use of the brushes or rollers to apply a thin resin coat. You can use a brush of 10 cm for this purpose. For around 1 metre of square area, around 250 ml resin should be used. This is the primer coat, and it should be allowed to harden for a minimum of two hours. (It’s best if it’s left to harden overnight.)

Ensure that the pond is completely dry while fibreglass is added to it. Should the area that was primed get wet, then it should be dried out before proceeding to the next step.

·      Step Four

During this step, it’s best to work with only 1/2 sq m of area at a time. First, another coat of resin, together with the hardener, will need to be applied on the surface of the pond. As soon as this is done, fibreglass matting 1 square will need to be applied on the surface that’s still wet.

Use your brush or rollers to apply even more resin on the surface of the matting. When the matting has been wetted out, you can proceed to the next step. Around 1/2 L of resin should be used per 1/2 m of matting.

·      Step Five

Now, it’s time to place the second layer of the 1/2 m matting on top of the layer that you just applied. The second layer of matting should be thoroughly coated using resin. A metal roller can help in consolidating both these layers. It also helps to get rid of wrinkles or air.

If the wetting out process fails, and if the mat or the resin has not been consolidated, it could end up pin-holing the project. Pin-holing is what happens when dry fibres manage to make their way through the surface of the gel coat. This can result in leakages that are difficult to fix.

·      Step Six

Repeat steps four and five in each area of the pond. The joins in each of the layers that are placed should overlap with the layer that is succeeding. This should be applied to the whole pond.

·      Step Seven

Finally, the flow coat will need to be applied. This should ideally be applied as soon as the structure is dry. This will help to ensure that the bond is good. Around 2 kg of the flow coat will need to be mixed with the catalyst. For around 20cc of the flow coat, you’ll need to add 1 L of the catalyst.

Using a paintbrush, paint the flow coat that’s been catalyzed, on every surface of the pond.


If you want to fibreglass your pond, this guide can help you learn what the steps involved in the process are. Furthermore, if you need any assistance, you can always reach out to your Perth pool installer for advice. From what materials you’ll need, to how to prepare your pond, follow the steps in this guide to easily fibreglass any pond. Be careful regarding the measurements you’re using, and adhere to the right ratio of catalyst and resin, as well as the catalyst and the flow coat. This will help you fibreglass your pond more effectively.

Written Lifestyle Contributor by Rosy