Question 1

How do I calculate how many deck boards I need?

Accepted Answer

Divide the deck width (perpendicular to joists) by the actual board face width including the gap. For 5.5 inch boards with a 1/4 inch gap, use 5.75 inches. Multiply by the deck length to get total linear feet.

Question 2

How far apart should deck joists be?

Accepted Answer

Standard deck joist spacing is 16 inches on center for residential decks. Use 12 inches on center for diagonal board layouts or heavy loads, and 24 inches on center only for thick 2x6 boards on light-duty decks.

Question 3

How many deck screws do I need per board?

Accepted Answer

Use 2 screws per joist per board. For a 12 foot board on 16 inch joist spacing with 10 joists, that's 20 screws per board. Always buy 10% extra for stripped or broken screws.

Question 4

How deep should deck footings be?

Accepted Answer

Deck footings should extend below the frost line in cold climates — typically 36-48 inches deep. In frost-free areas, 12-24 inches is common. A typical footing is 8-12 inches in diameter.