Design a wooden deck for an imaginary back yard. Draw it to scale. Calculate the boards needed and the cost.
A 4 m × 5 m deck, boards 2.4 m × 0.14 m at $9 each
Deck area = 20 m². Board area = 0.336 m². 20 ÷ 0.336 ≈ 60 boards. Add 12% waste → 67 boards. Cost ≈ 67 × $9 = $603.
Order 10–15% extra for cuts, off-cuts and the odd split board. Running out halfway means a second delivery fee — real construction maths always pads the order.
Your deck area is 30 m² and each board covers 0.5 m². With 15% extra for waste, how many boards do you order?
Steps
1) Sketch the deck shape (rectangle is easy; L-shape is harder). 2) Decide board size (e.g. 2.4 m × 0.14 m). 3) Calculate the deck area. 4) Divide by board area to get number of boards. 5) Multiply by price per board.
Always order 10–15% extra for cuts and waste. Real construction maths includes safety margin.