Repairing a Garden Pond

Pond Repairs

It is unfortunate that no matter how carefully a pond is constructed and maintained, occasionally a leak will develop. This can have a devastating effect upon pond life, and remedial action must be taken swiftly. Sometimes, the decision should be taken to start again, for in the case of polythene, PVC and LDPE liners, repairs are rarely satisfactory.



However, the same does not apply to rubber liners, such as the butyl type. These are as easy to repair as a cycle tyre if you can locate the puncture. Repair kits for this kind of liner are readily available.

Once the problem has been located, the liner in the immediate vicinity must be allowed to dry out. Then the surface should be cleaned thoroughly with a scrubbing brush and, if necessary, roughened a little with a piece of glasspaper. This will help ensure a good bond once the adhesive has been applied. Cut a patch at least one-and-half-times the size of the damaged area, apply the adhesive and press down firmly. Leave the patch to dry for 12 hours, preferably longer, before refilling the pool with water. Some repair kits have self-adhesive patches which, once applied, can safely be subjected to water within half an hour.


pre-formed pools

Pre-formed pools that are made from any kind of plastic or PVC material are almost impossible for the home gardener to repair, but those made from fibreglass can be patched if necessary. For the most part, fibreglass pools should be immune to damage, but sometimes problems will occur in an inadequately supported pool if anyone stands in it while cleaning it out, or if a pool is being moved to another part of the garden and reinstalled.

When damage does occur, it is not too difficult to repair with an automotive repair kit containing fibreglass matting (follow the manufacturer’s instructions carefully). However, as it is best to repair the underside of the moulding, it will need removing from the ground and inverting.



Although regarded as permanent strong structures, concrete ponds can suffer, especially during the winter. While it is rare for a professionally constructed pool to leak badly, this still can occur in very severe weather if you do not take suitable precautions. The pressure of ice over a protracted period on a concrete pool structure can cause fracturing. To alleviate this risk, float a large piece of wood or several rubber balls on the pool during the winter months. If severe frost occurs, they will absorb some of the pressure, rather than the rigid walls of the pool.

Repairing a Garden Pond Sometimes, a concrete pool will suffer from flaking: the frost gets under the surface layer of concrete, causing it to bubble and lift. Rapid deterioration then sets in. In practical terms, little can be done by way of concrete repairs. However, it is often possible to reline such a pool with a rubber liner. This should be installed and secured in much the same manner as lining an excavation in the ground.

Fractures can usually be repaired satisfactorily, although even a good repair will be a potential site of weakness, and sometimes problems can recur. Clean the area of the leak with a stiff brush and wash off the dust and debris. Cut out the crack with a cold chisel, making a V-shaped groove along the fracture line, at least 2.5cm (1in) deeper than the obvious crack. Roughen the surface of the concrete with the chisel so that fresh concrete will adhere to it successfully.

Mix by volume one part cement, two parts sand and four parts gravel. Then add waterproofing compound and, when thoroughly mixed together, combine with water until you achieve a workable consistency. Apply the mixture with a plasterer’s trowel. This is a good strong mixture that should provide a seal. Some builders will recommend that the gravel content of the mixture be reduced to make it easier to fill the crack and to smooth, but for the amateur pond repairer, the full concrete mix, even if more difficult to lay and to smooth, will ensure an efficient repair.

The concrete must be allowed to dry out for several days. However, it must not be allowed to dry out too quickly, otherwise hairline cracks may appear in the surface. To prevent this, cover the repaired area with damp sacking and keep it damp until the concrete has set firmly. Then treat it with a sealing compound to prevent free-lime escaping into the pool when water is added, as this can harm the fish.



1. Allow the liner to dry out and then clean the surface thoroughly with a scrubbing brush. In order to ensure a good strong bond for the adhesive, rough the surface of the liner with sandpaper.

2. The area prepared should be substantially larger than that which is damaged. Use an adhesive which is specifically recommended for the purpose and apply liberally.

3. Place the patch firmly in position, paying particular attention to the edges. These must be stuck down firmly. Allow the patch to dry for at least 12 hours before refilling the pool with water.



1. Remove the pool unit from the ground and invert. Clean the whole area with a wire brush. Rub around the damaged area with glasspaper, then brush thoroughly to remove any dust.

2. Cut a piece of fibreglass matting up to twice the size of the damaged area and, carefully following the instructions, mix the resin and hardener. Then apply it with the ridged roller provided.

3. It could take a couple of days for the matting to set hard, so it is a good idea to carry out this job in a garage or similar outbuilding. Sand off any rough edges before reinstalling the pool.



1. Cut out the concrete around the crack, being sure to remove any damaged material. Cut a V shape which is sufficient to take enough concrete for proper uniting of new with old.

2. Fill with a strong concrete mix ideally with a water proofing compound incorporated. Apply with a plasterer’s trowel to ensure a smooth finish and tamp down firmly.

3. After the concrete has had an opportunity to dry thoroughly, paint with a sealing compound. It may be necessary to use a primer first in order to ensure that the sealant sticks.


17. March 2011 by admin
Categories: Gardening Ideas, Water Gardening/Water Features | Tags: , | Comments Off on Repairing a Garden Pond


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