We recently hired a plumber to replace a lot of the old plumbing in our house. The main stack was the original cast iron. The plumber claimed to have cracked a portion of it and, as a result, replaced a large section (maybe 10 to 12 feet) running between the first floor and attic with PVC. The old pipe in this area had a bend in it. The new PVC was installed without bends, but sits instead at a slight angle to the cast iron pipe it joins on either end, maybe 3 to 4 degrees. (Does this make sense?) This concerns me -- I can't believe the seal can be as good, and my ignorant feeling is that two pieces of joined pipe ought to be aligned straight to each other, rather than forcing the joint at angles. The plumbing contractor swears up and down that it's fine. Is he right? Is this up to code? Should I be concerned about strength or leaks at the joint?