This summer I installed a new Selkirk chimney. I noticed that they are not as thick-walled as the older ones. So I am wondering about creasote build up. Are the new thin walled chimneys as good as the old one's when it comes to build-up? I had to clean the old chimney once a month during winter as the pipe is going through three floors or about 30 feet. It is easy since I can push the brush up through the basement, so there is no need to go on the icy roof.