i need some expert advice on built in copper gutters.House was built in 1923. has rusty metal. Going to replace with copper myself. the first area im going to do isa 18ft by 15ft car port    has very slight pitch hip roof  attatched to house.the shape and size of built in gutter goes like this @3in.down at   roof  8in across bottom of gutter then up @2in then across 8in then  down1.25in drip over crown on facia . my main question is  ……. useing 30in by 10ft copper ,  are rivited soldered joints the same as an expantion joint?? if not please detail  the differance  also is 16oz. copper ok.   im experieanced on a brake and a bad speller