Wow! I'm surprised the treated plywood lasted that long. And not bad for a liner lasting 10 years. I read they generally will go about 7 years plus.

I'm building a spa using concrete blocks with plans I bought from custombuiltspas.com and the manual I got has ALOT of information and pictures. The best I have ever seen. He also has a manual for larger swim spas and small pools using the same method with reinforced walls so thats why I was asking. But I'm still surprised with the plywood that long!

Warren