Deck Calculator Lowes

Deck Material Estimator

function calculateDeckMaterials() { var deckLength = parseFloat(document.getElementById('deckLength').value); var deckWidth = parseFloat(document.getElementById('deckWidth').value); var deckingBoardWidth = parseFloat(document.getElementById('deckingBoardWidth').value); var joistSpacing = parseFloat(document.getElementById('joistSpacing').value); var beamSpan = parseFloat(document.getElementById('beamSpan').value); var postSpacing = parseFloat(document.getElementById('postSpacing').value); var resultDiv = document.getElementById('result'); resultDiv.innerHTML = "; // Clear previous results if (isNaN(deckLength) || isNaN(deckWidth) || isNaN(deckingBoardWidth) || isNaN(joistSpacing) || isNaN(beamSpan) || isNaN(postSpacing) || deckLength <= 0 || deckWidth <= 0 || deckingBoardWidth <= 0 || joistSpacing <= 0 || beamSpan <= 0 || postSpacing <= 0) { resultDiv.innerHTML = 'Please enter valid positive numbers for all fields.'; return; } // 1. Deck Area var deckArea = deckLength * deckWidth; // 2. Decking Boards (assuming boards run along the Deck Length) var numDeckingRows = Math.ceil((deckWidth * 12) / deckingBoardWidth); var totalDeckingLinearFeet = numDeckingRows * deckLength; var numDeckingBoards12ft = Math.ceil(totalDeckingLinearFeet / 12); // For 12-foot boards var numDeckingBoards16ft = Math.ceil(totalDeckingLinearFeet / 16); // For 16-foot boards // 3. Joists (running along the Deck Width, supported by beams along the Deck Length) // Add 1 for the rim joist/first joist var numJoists = Math.ceil((deckLength * 12) / joistSpacing) + 1; var joistLength = deckWidth; // Each joist spans the deck width var totalJoistLinearFeet = numJoists * joistLength; // 4. Beams (running along the Deck Length, supporting the joists) // This calculation assumes a ledger board against the house and then beams spanning the width. // Number of spans needed across the deck width var numBeamSpans = Math.ceil(deckWidth / beamSpan); // Total beams = ledger + intermediate beams + outer beam var numBeams = numBeamSpans + 1; var beamLength = deckLength; // Each beam spans the deck length var totalBeamLinearFeet = numBeams * beamLength; // 5. Support Posts (supporting the beams) // Posts per beam: (Deck Length / Post Spacing) + 1 for the ends var postsPerBeam = Math.ceil(deckLength / postSpacing) + 1; var numPosts = numBeams * postsPerBeam; // 6. Concrete Footings (one per post) var numFootings = numPosts; var resultsHtml = '

Deck Material Estimate:

'; resultsHtml += 'Total Deck Area: ' + deckArea.toFixed(2) + ' sq ft'; resultsHtml += '

Decking Boards:

'; resultsHtml += 'Approximately ' + totalDeckingLinearFeet.toFixed(0) + ' linear feet of decking boards.'; resultsHtml += 'This translates to:'; resultsHtml += '

'; resultsHtml += '
• ' + numDeckingBoards12ft + ' 12-foot decking boards (e.g., 2x6x12)
'; resultsHtml += '
• ' + numDeckingBoards16ft + ' 16-foot decking boards (e.g., 2x6x16)
'; resultsHtml += '

'; resultsHtml += '

Joists:

'; resultsHtml += 'Approximately ' + numJoists + ' joists, each ' + joistLength.toFixed(0) + ' feet long.'; resultsHtml += 'Total joist linear feet: ' + totalJoistLinearFeet.toFixed(0) + ' linear feet.'; resultsHtml += '

Beams:

'; resultsHtml += 'Approximately ' + numBeams + ' beams, each ' + beamLength.toFixed(0) + ' feet long.'; resultsHtml += 'Total beam linear feet: ' + totalBeamLinearFeet.toFixed(0) + ' linear feet.'; resultsHtml += '

Support Posts & Footings:

'; resultsHtml += 'Approximately ' + numPosts + ' support posts.'; resultsHtml += 'Approximately ' + numFootings + ' concrete footings.'; resultsHtml += 'Note: These are estimates. Always account for waste (typically 10-15%), local building codes, and specific material dimensions when purchasing. Consult with a professional for precise planning.'; resultDiv.innerHTML = resultsHtml; }

Planning Your Deck Project with a Material Calculator

Building a deck is an exciting home improvement project that can significantly enhance your outdoor living space. However, one of the most challenging aspects of deck construction is accurately estimating the materials you'll need. Over-ordering leads to wasted money and materials, while under-ordering causes delays and extra trips to the store. This is where a reliable deck material estimator, like the one above, becomes invaluable.

What is a Deck Material Estimator?

A deck material estimator is a tool designed to help you calculate the quantities of various components required for your deck project based on its dimensions and your chosen specifications. Instead of guessing or manually performing complex calculations, you can input key measurements and instantly receive an estimate for decking boards, joists, beams, posts, and footings.

Key Components of a Deck and How They're Calculated

1. Decking Boards

These are the boards that form the walking surface of your deck. Their quantity depends on the total area of your deck and the actual width of the decking boards you choose (e.g., a nominal 6-inch board is often 5.5 inches wide). The calculator determines how many rows of boards are needed to cover the deck's width and then multiplies that by the deck's length to give you total linear feet. It also provides estimates for common board lengths like 12-foot and 16-foot boards.

Calculation: (Deck Width in inches / Decking Board Actual Width) * Deck Length in feet

2. Joists

Joists are the horizontal framing members that support the decking boards. They typically run perpendicular to the decking. The spacing between joists (often 12, 16, or 24 inches on center) is crucial for deck stability and depends on your decking material and local codes. The calculator determines the number of joists needed across the deck's length, plus an additional joist for the rim or end.

Calculation: (Deck Length in inches / Joist Spacing) + 1

3. Beams

Beams are larger structural members that run perpendicular to the joists, providing support for them. They transfer the deck's load to the support posts. The number of beams depends on the deck's width and the maximum span your chosen beam material can safely achieve (Beam Span). A typical deck will have a ledger board (attached to the house), an outer beam, and potentially intermediate beams for wider decks.

Calculation: (Deck Width / Beam Span) + 1 (for ledger and outer beam)

4. Support Posts

Posts are vertical members that support the beams, transferring the deck's weight to the ground. Their quantity depends on the number of beams and the maximum distance allowed between posts along each beam (Post Spacing). Proper post placement is vital for structural integrity.

Calculation: Number of Beams * ((Deck Length / Post Spacing) + 1)

5. Concrete Footings

Footings are concrete bases that sit below the frost line, providing a stable foundation for your support posts. Each post requires a footing to prevent settling and ensure the deck remains level and secure over time. The number of footings will directly correspond to the number of support posts.

Calculation: Equal to the Number of Support Posts

How to Use This Deck Calculator

1. Measure Your Deck: Determine the desired overall Length and Width of your deck in feet.
2. Choose Decking Board Width: Input the actual width of the decking boards you plan to use (e.g., 5.5 inches for a 2×6 nominal board).
3. Specify Joist Spacing: Select your desired joist spacing (e.g., 16 inches on center is common).
4. Determine Beam Span: Input the maximum distance your beams can span between support posts. This depends on the beam material and size.
5. Set Post Spacing: Enter the desired distance between your support posts along each beam.
6. Calculate: Click the "Calculate Materials" button to get your estimated material list.

Important Considerations

• Waste Factor: Always add a waste factor (typically 10-15%) to your calculated material quantities to account for cuts, mistakes, and damaged pieces. This calculator provides raw estimates.
• Local Building Codes: Deck construction is subject to local building codes, which dictate minimum sizes for lumber, joist/beam spans, post depths, and more. Always consult your local building department before starting your project.
• Material Types: This calculator provides quantities, but the specific type of wood (pressure-treated, cedar, composite) or fasteners will impact cost and durability.
• Stairs and Railings: This calculator focuses on the main deck structure. Remember to plan and estimate materials for stairs, railings, and other accessories separately.
• Professional Advice: For complex deck designs or if you're unsure, it's always best to consult with a professional contractor or structural engineer.

By using this deck material estimator, you can gain a clearer understanding of your project's material needs, helping you budget effectively and streamline your trips to the hardware store, like Lowe's, for your deck-building supplies.