How do you find the square footage of a deck
Andrew White
Published Mar 11, 2026
The first step for answering “how to calculate how much decking I need” is to determine your deck’s square footage, or area, by taking the length of your deck times the width (L x W). EXAMPLE: For a deck that is 16 feet long and 12 feet wide, multiply 16 by 12. This gives you 192 square feet, your deck’s total area.
How many square feet is a 12x12 deck?
How many square feet is a 12×12 room? The square footage of a room 12 feet wide by 12 feet long is 144 square feet. Find the square footage by multiplying the width (12 ft) by the length (12 ft).
How many square feet is a 12 foot deck?
A 12×12 deck has a perimeter of 48′ and square footage of 144 square feet. And just for kicks, we’ll say that the joists are 16” on center. The joist spacing doesn’t matter too much for this example, except that we can determine the exact amount of fasteners needed (2 per board per joist).
How many square feet is a 20x20 deck?
Deck SizeSquare FeetAverage Cost12x20240$3,600 – $8,40014×20280$4,200 – $9,80016×16256$3,840 – $8,96020×20400$6,000 – $14,000How many deck boards do I need for a 12x12 deck?
For example, a 12-foot x 12-foot deck of 5/4 x 6 pressure treated wood decking on 16 inches on center spacing of joists will require: A 12-foot long deck with joists 16 inches on center will require 10 joists. 20 fasteners x 26 (number of rows of decking) = 520 fasteners. Add 10 percent to be safe.
How many square feet is a 16-foot deck board?
EXAMPLE: Say you’ve chosen the 16-foot standard width deck board. First, take the width (5.5 inches) and convert it into feet by dividing it by 12 inches, which gives you 0.45 feet. Then multiply 0.45 by 16 to get the board’s area: 7.33 square feet.
How many Trex boards do I need for a 12x12 deck?
Board lengthBoards required8 FT20612 FT13716 FT10320 FT83
How much does it cost to build a 12x12 screened in porch?
Average Cost to Build a Screened-In Porch The total costs $3 to $5 per square foot for materials, and $2 per square foot for labor. If you want to build a completely new porch with screen, you’ll pay $25 to $120 per square foot for the entire project.How do I calculate how much wood I need?
You can measure board feet by multiplying length x width x thickness in inches, and then dividing by 144. If ordering a large amount by board feet, just multiply the total board feet needed by the price per board foot for the total cost.
How many square feet are in a deck board?Calculating How Much Material to Purchase You’ll need the dimensions of the deck boards you hope to use. If you are using 2- by 6-foot boards, for instance, the square footage of each board is 12 square feet. For the deck size example provided above of 200 square feet, you would need 18 boards of this size.
Article first time published onHow do I calculate how many decking boards I need?
Extra boards will also be required depending on the width of the staircase, also allowing for 2 steps, add 1 x 3.6m standard decking board per step based on an example 700mm wide step with 5 cut lengths per step. Example, 5 x 900mm (width of step) = 4500 (total) / 3600 (length of board) = 1.25 boards x 2 (no.
Should deck joists be 2x6 or 2x8?
For upper-level decks, 2×10 is recommended as the minimum size to use for strong guard post connections. 2×6 joists should only be used on ground-level decks that do not require, and will not provide for, any guards. … Most decking is not strong enough to support longer spans than 16″.
How many deck blocks do I need for a 10x10 deck?
For example, a 10 x 10 floating deck needs four-deck blocks. Four deck blocks can hold 8 000lbs, almost twice the support necessary for a 10 x10 deck.
Can I use 2x6 for deck boards?
Wood decking is commonly available in 2×6 and 5/4 x 6 profiles. 5/4 x 6 is produced specifically for decking and is milled with a radius edge or bull nose. 2×6 is thicker and is stronger, but is also more expensive. Spacing between deck boards provide a few critical functions.
Is Trex more expensive than wood?
An obstacle for Trex is that composites cost a lot more than natural wooden decking. By Trex’s estimates, for a 16- by 20-foot deck, the materials outlay for its Transcend line are $2,714, almost five times that of regular wood ($577).
Are Trex decks worth it?
Composite decking is worth the money. It costs more upfront, but thanks to minimal maintenance costs and long life, the annual cost for the life of the fence is significantly cheaper for composite materials. If what you have in mind are the Trex decks of 15 years ago, you’d be surprised to see how far they’ve come.
How expensive is Trex?
Trex Decking Cost Trex decking costs $1,600 to $9,600, averaging about $4,800. That’s $5 to $12 per square foot for just decking boards and $5 to $15 per square foot for installation.
How do you calculate wood for a project?
TIP: To calculate board feet: rough standard thickness X actual width X actual length divided by 144. Use the thickness of the material you intend to start with, not end with. For example, the 3/4″ top will start from 4/4 lumber. The legs will start from 6/4 lumber.
How do you calculate square feet for wood?
Square Feet Step 1: Measure the width of your item in inches and then multiply times the height. Step 2. Multiply the width and height of all sides to be coated (including the top). Step 3: Add all of these totals together and divide by 144 to determine the total square feet you will need to cover.
How much lumber do I need for a 1000 square foot house?
House Construction So, a 1,000 square foot home would need 6,300 board feet to complete, while 12,600 board feet would be necessary for a 2,000 square foot home.
Does a screened in porch add square footage?
If you’re wondering whether you can count a screened porch in your home’s total square footage for a real estate listing, the answer is no, you cannot. … Screened porches, even if heated with space heaters, a fireplace, or our favorite infrared heaters, don’t count as square footage for a real estate listing.
How much does it cost to build a roof over a deck?
Average Cost to Build a Roof Over a Deck But we can give you an average range of prices that it would most likely fall within. They include: Adding any deck covering or enclosure will typically cost between $1,000 – $10,000. Adding a covered roof to your deck will typically cost between $3,000 – $10,000.
Is screened in porch worth the money?
Outdoor projects are among the best investments you can make in your home to improve its resale value, so it should be no surprise that most homeowners are able to get around a 75% return on investment in a screened-in porch.
What is the size of deck boards?
What Is the Standard Deck Board Size? Common deck board widths are 4”, 6” and 8”. The widths are readily available in most lumber or building supply stores, and the number of pieces easily calculated into deck dimensions. Other widths may be used for aesthetics and effect.
How do I calculate decking materials?
- Step 1: Calculate the surface area of your decking. Multiple the length (L) of your decking area by the width (W). …
- Step 2: Calculate the coverage of your deck boards. Add the deck board width (W) to the Expansion Gap Length (EGL). …
- Step 3: Calculate the number of boards required.
How do you estimate a decking job?
Labor costs will total just about two-thirds of the total project cost. With contractors charging, on average, about $35 per square foot. For an average deck size between 200 and 500 square feet, you can expect to pay out between $7,000 and $17,000 just for installation and labor.
What is the normal gap between decking boards?
Proper wood deck board spacing should have at least a 1/8 inch gap after the decking has dried out. If you install your wood or treated deck boards while they are still wet boards, then they should be attached without a gap between them.
How far apart should deck beams be?
Deck joists are typically spaced either every 12 inches or 16 inches on center. The maximum joist spacing you can use will depend on the size and allowable span of your joists.
How far can you run a 2x8 without support?
Using this rule, a 2×6 will span 9 feet, a 2×8 will span 12 feet, and a 2×10 will span 15 feet.
How many joists do I need for a 16 foot deck?
For example, when you space joists 16″ apart — which is standard for residential decks — a deck spanning 9 1/2′ would require 2-by-6 joists, a 13′ deck would need 2-by-8 joists and a 16′ deck calls for 2-by-10 joists.
Will deck blocks sink?
The deck blocks can sink if the soil under them erodes for some reason or the weight is unevenly distributed. That’s why it’s a good idea to use more than less. … Especially in loose soils or wet conditions which requires more weight distribution.