Thanks Gary I'll pass that on to my husband, he is usually the doer of such things but has been so busy this week that he was going to relegate. I think most of the plumbers do the strapping now because there is a lot more requests for it and perhaps the Code has changed from what was required 25 years ago. Interesting I've never heard about butressing though, I'll see what Hydro recommmends. Thanks again.

My father-in-law was just suggesting that I construct a supporting floor for the new one, as the place in the crawlspace where the new tank is going has a slope to the concrete. Now I'll have to rethink how I am going to attach the framed section below the pan to the concrete groundseal. hmmm.....major project for me....