Fibreglass Pond Building FAQ'S

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Q: I want to make a filler paste for pond work. I wondered if cement being a fine powder and easily available would be suitable for such use. I would use it to gap fill or to try some mould experiments. Are there any contra indications for such use? I would be grateful for your advice.

A: Do NOT use resin with cement it doesn't work. The following powders are ideal: Fillite (fly ash) Talc Marble Flour DRY bath sand Most powders are available from us, the most popular being Fillite which is approx. £17.50 inc. VAT for a 20kg bag. Process for mixing filler to resin: 1. Mix the resin and hardener in the normal way 2. Mix in the filler ready to use.

Q: I would like to build a pond in my back garden, a friend recommended that I should build a concrete structure to form the base for a glass fibre pond what is your advice?

A: A concrete base is not necessarily needed for building a glass fibre pond. We recommend that you build your pond in 4 stages:

  • 1. Dig your hole to the required shape and size
  • 2. Flatten the mud to give an even surface to work on
  • 3. Lightly render with sand and cement then lightly sand the surface leaving a smooth base.
  • 4. You are now ready to laminate your pond with resin and mat.

Q: I have a concrete pond that keeps leaking, can you help?

A: A glass fibre laminate can be used to coat a concrete pond but you are, in effect forming another pond inside your original one. We recommend using 2 layers of matting with the appropriate resin and gel coat to form a pond that will last many years within a concrete base. Once the glass fibre laminate goes hard the cracking and ground movement will not effect the laminate at all (it has a certain amount of give).

Q: Could you please let me know whether you stock a product that would glue gravel/small stones to a pond liner, the product would obviously have to be safe for fish and pond life as well as being watertight? I have thought of trying pond repair glue, but I can only purchase this in small kits?

A: Am I right in presuming that the pond liner that you are talking about is a rubber type one? If so, then I am afraid that we do not have any details of adhesives for this type of product, we only deal with GRP ponds (glass reinforced plastic). I suggest that you try the lining manufacturer. Sorry we couldn't be of any help.

Q: Would you advise the use of a surface tissue on top of the csm to prevent wicking in the case of pond lining. Or will your top coat be sufficient to prevent this problem?

A: Surface tissue has got a very high resin pick up so is normally used against gel coat when working on a "mould". We do not see any advantage in the use of surface tissue when sheathing a pond. Providing the chopped strand laminate is properly rolled and consolidated, the flow coat will be sufficient in achieving a smooth surface and prevent wicking.

Q: Once flow coat has been used, is it possible to bond to the wax-modified resin if changes or repairs are needed to the structure?

A: Yes it is possible, you need to clean the area thoroughly (preferably using Acetone) then sand back the surface before carrying out your repair.

Q: I am building a pond at the moment from GRP. So far I have used two layers of matting with resin, colouring and catalyst, one layer of surface tissue and two layers of flowcoat. However I have a leak in the pond but can't find it. Could you tell me the common/possible reasons for leaks and any way in which I can try and find the leak.

A: The usual problem is that the matting has not been rolled out/wetted out correctly with the metal roller which results in dry areas of matting that penetrate through the flowcoat. This enables the water to come through the laminate. If this is the case you will see very small pinholes in the flow coat that need filling - the easiest way is to plug the hole with plasticine then overcoat with another layer of matting and gel coat (please contact us for further advice if you are going to take this route).