In Genesis, Noah uses pitch to waterproof the Ark.
Genesis 6:14 instructs Noah to cover the Ark with pitch inside and outside. Pitch is a thick, waterproofing substance made from tar-like natural materials or heated organic compounds. Applying it to both surfaces would help seal the vessel against water.
The instruction appears alongside the Ark’s construction details, including its gopher wood, compartments, and dimensions. The text does not provide a modern chemical recipe for the pitch, so readers should not assume that it refers to one uniquely identified industrial product.
Pitch is sometimes confused with the wood named in the same verse. Gopher wood describes the material used to build the Ark, while pitch describes the coating applied to make it watertight. They serve different purposes in the construction instructions, and the answer to the waterproofing question is therefore “pitch.”