Decking Calculator

Deck Length ($ L_d $):

Deck Width ($ W_d $):

Board Length ($ L_b $):

Board Width ($ W_b $):

Cost per Board ($ C_b $) ($):

Fastener Type:

Screws Pack Size:

1. What is Decking Calculator?

Definition: This calculator estimates the number of decking boards, fasteners (screws or hidden fasteners), and total cost needed to build a deck based on its dimensions, board size, and material costs.

Purpose: It is used in construction and DIY projects to plan decking projects, ensuring accurate material estimation and cost calculation for decks on patios, gardens, or outdoor spaces.

2. How Does the Calculator Work?

The calculator uses the following equations:

$ \text{Deck Area} = L_d \times W_d $
$ \text{Board Area} = L_b \times W_b $
$ \text{Boards Needed} = \lceil \frac{\text{Deck Area}}{\text{Board Area}} \times 1.1 \rceil $
$ \text{Screws Needed} = \frac{7}{2} \times \text{Deck Area} \quad (\text{or} \quad \frac{7}{4} \times \text{Deck Area} \quad \text{for hidden fasteners}) $
$ \text{Total Cost} = (\text{Boards Needed} \times C_b) + \text{Pack Cost} $

Where:

$ L_d $: Deck length (ft, converted from selected unit);
$ W_d $: Deck width (ft, converted from selected unit);
$ L_b $: Board length (ft, converted from selected unit);
$ W_b $: Board width (ft, converted from selected unit);
$ C_b $: Cost per board ($);
$ \text{Pack Cost} $: Cost of the selected fastener pack ($).

Steps:

Enter the deck length ($ L_d $) and width ($ W_d $) with their units.
Enter the board length ($ L_b $) and width ($ W_b $) with their units.
Enter the cost per board ($ C_b $).
Select the fastener type (screws or hidden fasteners).
Select the fastener pack size.
Convert all measurements to feet.
Calculate the deck area: $ L_d \times W_d $.
Calculate the board area: $ L_b \times W_b $.
Calculate the number of boards: $ \lceil \frac{\text{Deck Area}}{\text{Board Area}} \times 1.1 \rceil $.
Calculate the number of fasteners: $ \frac{7}{2} \times \text{Deck Area} $ (or $ \frac{7}{4} \times \text{Deck Area} $ for hidden fasteners).
Calculate the total cost: $ (\text{Boards Needed} \times C_b) + \text{Pack Cost} $.
Display the results: boards needed, fasteners needed, and total cost.

3. Importance of Decking Calculation

Calculating decking requirements is crucial for:

Material Estimation: Determining the exact number of boards and fasteners to avoid over- or under-purchasing.
Cost Planning: Estimating the total cost of the project to stay within budget.
Project Efficiency: Ensuring the deck is built with minimal waste and sufficient materials for a durable finish.

4. Using the Calculator

Example 1 (Screws, Same Units): Calculate the decking requirements:

Deck Length: $ L_d = 20 \, \text{ft} $;
Deck Width: $ W_d = 13 \, \text{ft} $;
Deck Area: $ L_d \times W_d = 20 \times 13 = 260 \, \text{ft}^2 $;
Board Length: $ L_b = 8 \, \text{ft} $;
Board Width: $ W_b = 6 \, \text{in} $;
Convert $ W_b $: $ W_b = 6 / 12 = 0.5 \, \text{ft} $;
Board Area: $ L_b \times W_b = 8 \times 0.5 = 4 \, \text{ft}^2 $;
Boards Needed: $ \lceil \frac{260}{4} \times 1.1 \rceil = \lceil 71.5 \rceil = 72 $;
Screws Needed: $ \frac{7}{2} \times 260 = 910 $;
Selected Screws Pack: 1000 ($98);
Cost per Board: $ C_b = 7 \, \$ $;
Boards Cost: $ 72 \times 7 = 504 \, \$ $;
Total Cost: $ 504 + 98 = 602 \, \$ $;
Result: $ 72 \, \text{boards} $, $ 910 \, \text{screws} $, Total Cost: $ 602.00 \, \$ $.

Example 2 (Hidden Fasteners, Mixed Units): Calculate the decking requirements:

Deck Length: $ L_d = 5 \, \text{m} $;
Convert $ L_d $: $ L_d = 5 \times 3.28084 = 16.4042 \, \text{ft} $;
Deck Width: $ W_d = 3 \, \text{m} $;
Convert $ W_d $: $ W_d = 3 \times 3.28084 = 9.84252 \, \text{ft} $;
Deck Area: $ 16.4042 \times 9.84252 = 161.458 \, \text{ft}^2 $;
Board Length: $ L_b = 2.5 \, \text{m} $;
Convert $ L_b $: $ L_b = 2.5 \times 3.28084 = 8.2021 \, \text{ft} $;
Board Width: $ W_b = 6 \, \text{in} $;
Convert $ W_b $: $ W_b = 6 / 12 = 0.5 \, \text{ft} $;
Board Area: $ 8.2021 \times 0.5 = 4.10105 \, \text{ft}^2 $;
Boards Needed: $ \lceil \frac{161.458}{4.10105} \times 1.1 \rceil = \lceil 43.29 \rceil = 44 $;
Hidden Fasteners Needed: $ \frac{7}{4} \times 161.458 = 282.5515 $;
Selected Hidden Pack: 500 ($75);
Cost per Board: $ C_b = 6 \, \$ $;
Boards Cost: $ 44 \times 6 = 264 \, \$ $;
Total Cost: $ 264 + 75 = 339 \, \$ $;
Result: $ 44 \, \text{boards} $, $ 283 \, \text{hidden fasteners} $, Total Cost: $ 339.00 \, \$ $.

5. Frequently Asked Questions (FAQ)

Q: Why do we add 10% to the number of boards?
A: The 10% waste factor accounts for cutting losses, defects, or errors during installation, ensuring you have enough boards to complete the project.

Q: What is the difference between screws and hidden fasteners?
A: Screws are visible and go through the board into the joist, while hidden fasteners are installed underneath or between boards for a cleaner look. Hidden fasteners typically require fewer units per square foot.

Q: Can this calculator account for irregularly shaped decks?
A: This calculator assumes a rectangular deck. For irregular shapes, you may need to break the deck into rectangular sections and calculate each separately.