In Genesis, Noah used pitch to seal or waterproof Noah’s Ark.
Genesis 6:14 instructs Noah to cover the ark inside and outside with pitch. The Hebrew wording is related to a term for covering or coating, and pitch generally means a sticky waterproofing substance derived from bitumen, tar, or a similar material. The passage does not specify the exact chemical composition used.
Pitch was a practical choice for ancient boatbuilding because a coating could help keep water from entering seams and joints. The ark’s construction instructions also mention compartments and a window, suggesting a large enclosed vessel rather than an ordinary open boat.
Wax and resin are sometimes offered in retellings because they can also waterproof materials, but neither is the substance named in Genesis. The text’s important point is that the timber was coated on both sides, providing protection during the Flood narrative.