In Genesis, Noah’s Ark was coated with pitch inside and outside.
Genesis 6:14 instructs Noah to make the ark from gopher wood and to cover it with pitch, or a waterproofing substance, within and without. The coating would have helped seal the wooden structure against water, although the passage does not provide a modern chemical formula.
Translations vary in how they render the Hebrew term. English Bibles commonly use “pitch,” while some translations describe it as bitumen or a related waterproofing material. This variation reflects uncertainty about both the ancient word and the precise construction technology intended.
The instruction is not the same as saying the ark was built from tar. The text distinguishes the wood used for the vessel from the substance applied as its protective coating. Similar bituminous waterproofing was known in the ancient Near East, making the detail consistent with regional building practices.