A vent sealing device includes an elongated tubular member having an inner tube with a collar at the upper end of the inner tube, and a cap having an upper interior surface configured to receive the inner tube assembly, a lower interior surface configured to receive said outer tube, and a screen configured to remove debris positioned along the top of the assembly. A vent sealing system includes a roof attachment unit that includes an elongated base structure having an opening that includes a flexible sleeve protruding outward therefrom.