In Genesis, pitch covered Noah’s Ark to make it watertight.
Genesis 6:14 tells Noah to cover the ark with pitch inside and outside. Pitch is a waterproofing substance traditionally associated with tar, bitumen, or resinous material. The Hebrew wording is related to the broader idea of coating or covering, and translations differ slightly in how they render the substance.
This instruction complements the ark’s dimensions and wooden construction. Wood alone would allow water to enter through joints and gaps, so a sealant would be necessary for any large wooden vessel. The text does not describe a modern construction method or specify the exact chemical composition of the coating.
The biblical story also says the ark had a window, a door, and three levels. Pitch should not be confused with the wood itself: gopher wood is named as the building material, while pitch is the protective coating applied to the finished structure.