change in flue diameter

Is the change in furnace flue diameter from smaller to larger ok and is this metal duct tape oik for the transition? it seems i remember that the pipe can only be attached with screws?




It doesn’t look proper. And it looks too close to combustibles where it penetrates the roof sheathing.

The second image is too blurry for me.

so is going from a smaller to larger flue diameter ok to be made with metal tape?

The transition joint in the attic chimney pipe (from smaller to larger) does not appear proper and the chimney pipe is too close to combustible at the roof penetration. Recommend repairs, as needed for safe operation, by qualified professional.

thanks Larry.