According to Genesis, pitch coated Noah’s Ark inside and outside. Genesis 6:14 instructs Noah to cover the vessel with pitch, a waterproofing substance intended to seal the wooden structure against water.
The Hebrew word translated as “pitch” is related to a term for covering or ransom, and translations vary in their precise wording. Some versions use “bitumen,” “tar,” or another waterproof coating. The text’s practical point is consistent: the Ark was to be made watertight on both surfaces.
Pitch is not the same as gopher wood, which Genesis names as the construction material. Nor is it the same as the Flood water surrounding the Ark. Ancient boats commonly used bitumenous or resinous substances for waterproofing, but the biblical passage does not identify a modern chemical formula or provide a surviving sample from the Ark.