Hi guys,

Is it possible to pave a wooden pond frame with cement, as an alternative liner?

I guess anything is possible, but the cement can leach chemicals into the water and alter the pH, so I wouldn't do it. The big koi keepers typically build very deep ponds (6-8 feet deep) by using block walls and mortar. Then they use liners inside that OR paint on a marine grade type of coating. It's like liquid fiberglass which cures and creates the permanent lining. I get the impression that it's a lot more hassle and more expensive than rubber lining however.

If you're building a timber frame/wall, then go the easy way and put a liner in the thing. A good quality rubber liner will last for years, doesn't leach anything into the water, won't crack over time and can even be plumbed for a bottom drain if you wish.

Sounds like a lot of work and not to safe for the fish. You could buy a stock tank and build a wooden frame around it to make it look nicer.