Sealing Joints in Pipes to Make Them Watertight

This page is the CodyCross answer for the clue below from Underground Worlds, Group 2168, Puzzle 4 (Gua Tempurung).

Question is: Sealing Joints in Pipes to Make Them Watertight

and the answer is: CAULKING

Word Meaning:

CAULKING — present participle and gerund of caulk

Definitions from Wiktionary.