AFTER - The area of liner these pictures were taken from. Now water tight.
BEFORE - Bloodworm Damage These holes are about 8-10mm long and are caused by the larvae of midges that live in the pond. They have a soft muddy outer tube/case in which they live and gnaw away at the butyl liner over a prolonged period of time. You can see from the picture that the liner is very badly scared with hundreds of similar areas of damage. This can substantially weaken the liner and cause premature failure. It is impossible to prevent these organisms populating your pond, just be aware that if you cant find the hole after searching high and low, you might just have to look very closely indeed as sometimes these holes do not appear until you stretch the liner a little.
Midge Larvae - These are numerous and impossible to control. You might be lucky that your pond inhabitants control them for you, but if not you might have the same problem as seen in the image alongside. You'll only know about when you pond leaks!
Caddis Fly Larvae - This insect usually hides under the folds of the liner away from the hungry mouths of fish. But it likes to gnaw at pond liner to add to its carapace. They can make small circular holes on your liner, up to 5mm in diameter.
Crack in a rendered fountain feature. The crack was caused by unequal movement between the lower and raised parts of the structure. Now cut out to reveal the fault and pressure washed out to remove the dust.
Drying the crack ready to receive a sealant bead.
Sealant bead applied.
Pointed back up with a waterproof render.
Same project, just a double crack where the fault overlapped. the pond was then completely sealed with an epoxy resin for a long lasting waterproof finish.
Here is the project in its entirety. As winter was approaching, the client asked us to wrap her fountain to prevent it getting frosted. We now do this every year for her. The pond is still holding its level some 5 years on.