See guide at the footer of this page for insights on selecting the appropriate screws for both exterior and interior finish carpentry projects.
Choosing the Right Screws: A Guide for Exterior & Interior Finish Carpentry
a. Lengths:
1-5/8": For 3/4" thick boards and 5/4" boards with a joist system.
2" to 2-1/2": For typical 5/4" deck boards.
3": For thicker decking materials.
3-1/2": For specialized construction techniques.
b. Diameter:
#6, #7, #8, #9, #10: Larger numbers indicate thicker screws. #8 and #9 are most common for decking.
c. Head Types:
Bugle Head: Commonly used because of its curved shape which allows easy countersinking without damaging the material.
Trim Head: Smaller head diameter, often used for composite decking.
Flat Head: Sometimes used, but less common than Bugle.
d. Additional Considerations:
Drive Type: Square or Star (Torx) drives are preferred for their strong grip and reduced risk of stripping.
Pilot Holes: Essential to prevent wood splitting.
Countersinking: Allows screw heads to sit flush or below the wood surface.
Finishing: Cover installed screws with wood filler, then sand, paint, or stain for a seamless appearance.
Materials: Use corrosion-resistant screws for humid environments.