According to Genesis, Noah covered the Ark with pitch. Genesis 6:14 instructs Noah to make the Ark’s compartments and cover it with pitch inside and outside, creating a waterproof coating.
Pitch is a general term for a sticky, waterproofing substance derived from natural bitumen, resin, or tar-like materials. The Hebrew wording is related to the root used for covering or atoning, and translations differ slightly in how they render the material. “Pitch” is the standard English term in many Bible translations.
The instruction concerns sealing the vessel, not its building material. Genesis separately identifies the wood used for construction and gives the Ark’s dimensions. Nor is pitch the same as a modern petroleum product in every translation or historical reconstruction. The text supplies the waterproofing function but does not provide a recipe, quantity, or archaeological proof of the Ark’s construction.