Abstract: Disclosed herein is a spacing device utilized in the construction of decks and the like from composite building planks. The spacing device generally comprises a straight length of material possessing a T-shaped cross-section. The vertical element (or leg) of the “T” is used to establish the space between the polymer planks of a deck. The horizontal element prevents the spacer from falling through the space established by the T's leg. The spacing device is fabricated of a strong, lightweight material such as aluminum to provide the durability and portability required by the nature of its usage. The present invention's design is simple and straightforward, and can be economically manufactured and sold.