In the Genesis Ark story, pitch covered the Ark inside and outside.
Genesis 6:14 instructs Noah to coat the vessel with pitch on both its inner and outer surfaces. Pitch is a thick, waterproofing substance traditionally made from tar, resin, or related materials. In the narrative, the coating helps explain how the wooden vessel could be sealed against water.
The Hebrew word translated as “pitch” is related to the concept of covering or atonement in some interpretations, but the immediate context is practical waterproofing. English translations may use terms such as bitumen or tar, depending on how they render the ancient material.
Pitch is not the Ark’s construction wood. Genesis separately mentions gopher wood for the vessel’s structure. The two details answer different questions: one identifies the building material, while the other identifies the sealant.