Thin Strips of Wood That Make Space for Insulation

This page is the CodyCross answer for the clue below from Photography, Group 2010, Puzzle 3 (Fill Flashes).

Question is: Thin Strips of Wood That Make Space for Insulation

and the answer is: FURRING

Word Meaning:

FURRING — present participle and gerund of fur

Definitions from Wiktionary.