According to Genesis, Noah was told to cover the Ark with pitch.
Genesis 6:14 says that Noah should cover the ark inside and outside with pitch. Pitch is a thick, waterproofing substance traditionally made from tar or resin. In the narrative, it would seal the wooden structure and help keep water from entering.
The Hebrew wording creates a notable word connection: the verb commonly translated “cover” is related to the term often rendered “pitch.” English translations preserve the practical meaning, even though the original wordplay is harder to reproduce.
Pitch is not the same as ordinary paint or a decorative coating. Ancient boats and containers commonly used bitumen, tar, or resinous materials for waterproofing. The Genesis instruction therefore fits a wider ancient Near Eastern tradition of sealing wooden vessels, although the Ark’s enormous scale remains a feature of the story itself.