In the biblical Noah’s Ark story, pitch coated the ark inside and outside. Genesis 6:14 tells Noah to cover the vessel with pitch after describing its wooden construction.
Pitch is a waterproofing substance made from a thick, sticky material such as bitumen or tar. Applying it to both surfaces would help seal the ark against water. The Hebrew word translated as “pitch” is related to the verb for covering or atoning, though the practical instruction in the passage concerns waterproofing the vessel.
This detail is sometimes confused with the ark’s building material. Gopher wood describes what the ark was made from, while pitch describes the protective coating. The account also mentions compartments, a door in the side, and a window, giving the vessel several features associated with a sealed floating structure. The text does not identify a precise chemical recipe for the pitch.