Stand the two 36” long sections of pipe next to each other so that the top end of each pipe is the end with the pre-drilled screw holes. Notice that the top of one pipe has the pre-drilled screw holes below a ridge. We will call this Pipe #1. The other pipe has the pre-drilled screw holes above a ridge. This will be Pipe #2. Pipe #2 will slip into the top of Pipe #1. The end of Pipe #2 without the pre-drilled screw holes will slide down inside the top of Pipe #1.

When you have found the right length for your installation, use the holes in the top of Pipe #1 to align and drill through Pipe #2. Then install the 4 sheet metal screws provided.

You may notice that installing the pipe in this way leaves you with the crimped end of the pipe pointing down. This is the correct alignment for stove pipe. Installing pipe with the smaller (or crimped) end pointing down allows condensation to run down the inside of the pipe and back to the stove instead of running outside the pipe, creating ugly drip marks. Many people think that installing stovepipe with the crimped end down will allow smoke to leak out. This is not true. Provided your chimney system has sufficient draft, smoke will not escape through the joints with the crimped ends pointing down.