Install new flue venting that is rotted out . 2 6 inch 45 . 18 feet of six inch gas venting . Install new straps . 5 foot x 7 3 feet x1 2 foot x 1 45 x 3 Riser 90 x1 6-4 reducer 10 foot 4 inch 4 inch 90 x1 6 inch straps x6