slightly off topic - pond liner problem

[gray_bale]

I have a pond that came with the house. The pond now has a leak. I know the leak is on a fold.

But after +10years, how do I know whether the liner is PVC or Butyl.

Would I still expect butyl to still be rubbery and stretchable ?

Any advice

[Carltonian Man]

I've found old butyl (15+ years) to be hard and tough but not brittle/prone to cracking. The plasticisers in PVC however can migrate leaving it rigid and very likely to crack. Don't know if this helps at all.

[greenorelse]

Staying nicely off-topic, can anyone help me? Our pond has recently dropped in level, despite rain, meaning a leak has somehow occurred. It's a large pond, butyl lined and only around five years old.

Firstly, I'm puzzled why the level should suddenly drop, why a leak should suddenly occur. Secondly, I've no idea how to find the leak! Has anyone any tips for finding it? Obviously, it's somewhere around the new water level! But it's such a large pond, I don't know where to start.

[MKG]

@gray_bale ... If the culprit is a fold which has cracked, it's very likely to be PVC. Butyl tends not to give way like that.

@greenorelse ... There are two main reasons for a leak. One is that the SEAM of the liner has given way (which is the only thing which is ever covered by guarantee) and the other is animals. Dogs and cats can easily puncture a lining, but the usual culprit is a bird - a heron having a poke around (if the puncture is well below the normal waterline) or, if the puncture is just below the normal waterline, a blackbird going after tadpoles.

Whatever the cause, there's only one way to find the leak - get down on your hands and knees (on your belly, in fact) and run your fingers and eyes all along the new waterline.

Best of ...

Mike

EDIT: Forgot the third cause - a tree root coming inwards can go straight through a liner.

[oldjerry]

I'm sure you'd not do this,and it's one of the above culprits,but if your layer of sand wasn't sufficient, over time a stone can easily penetrate the liner , given the weight of the water.

(even more off-topic,anyone looking for a cheap effective pond,scout about for an old GRP boat,free or next to nothing,and sink it to ground level,worked for me anyhow.)