What coating does Genesis say Noah put on the Ark?

Genesis says Noah coated the Ark with pitch.

Genesis 6:14 instructs Noah to cover the vessel with pitch inside and outside. Pitch is a waterproofing substance, traditionally understood as a tar-like or bituminous material used to seal wood and keep water from entering through joints.

The instruction fits the practical purpose of the coating: a large wooden vessel would need sealed seams and protected surfaces. The biblical text gives the coating as part of the construction directions, together with the ark's compartments, dimensions, and opening.

Translations sometimes use related terms such as tar or bitumen, so readers may encounter different English wording. The answer is not wax, resin, or clay. “Pitch” is the established traditional English term in many translations, while the precise ancient substance cannot be identified with complete certainty from the short passage alone.