It’s One of the Smartest Ways to Add Square Footage (and Value) to Your Home
It can also be one of the most dangerous additions. Building a deck expands outdoor living space, but before adding or upgrading, find out what these seasoned builders recommend to help make it safer and more durable.
The house had it all: a prime lakefront location, with a deck wrapped around the second story offering stellar views of the water. But when Texas-based certified master home inspector Mike Marlow took a look, he saw danger.
Almost everything about the deck construction was wrong. Sections spanned 50 feet — about the length of a high school basketball court — in midair with no support columns underneath.
“I would have been worried about having anyone on that deck,” Marlow says.
Unfortunately, it’s a common sight in Marlow’s line of work. He says he can count on one hand the number of decks he’s seen built correctly, which helps to explain the number of injuries related to deck and porch failure. Approximately 33,270 people were hurt due to structural failures in decks, porches, railings and stairs over a four-year period, according to one study by the Consumer Product Safety Commission.
“I would have been worried about having anyone on that deck.” —Mike Marlow
The demand for decks and patios is increasing, according to the American Institute of Architects’ (AIA) Home Design Trends Survey. As residential real estate lots grow smaller and more scarce, “maximizing livable outdoor space tops the list of property enhancement desires,” says AIA Chief Economist Kermit Baker.
A deck can be a smart investment too. Remodeling magazine’s 2018 Cost vs. Value survey reports that a 16-by-20-foot midrange wood deck costing about $10,950 retains an 82.8 percent return on the investment.
If you’re planning to build a new deck (or looking to reinforce or upgrade an existing outdoor space), there are big decisions to make that can affect durability and safety — from choosing the deck material and sizing it to fit your home to selecting the fasteners that hold it all together. These are the questions you need to ask before building begins, and the answers you want to hear, according to pro builders who have seen the best and worst in deck construction.
Is there enough airflow for a deck?
Consider building a deck only if it can stand at least three feet off the ground, says Mark Milanese, a contractor and certified installation master in Chester County, Pennsylvania who specializes in building decks and patios. A deck at ground level will have minimal airflow under it, which may encourage mold and mildew and require more maintenance, says Milanese. “Worse, you’re actually creating a cushy new home for critters like snakes to live underneath,” says Milanese.
“If the door that would lead to the deck is less than three feet off the ground, consider installing a patio instead.” —Mark Milanese
Marlow’s advice: review the structure and safety basics set out in the American Wood Council’s (AWC) free deck construction guides.
Pro tip: Before building or repairing begins, contact the local building department to see if you need a permit, says Chris Peterson, author of “Deck Ideas You Can Use.” Local building codes are designed to promote safety, and can save headaches later.
Is the deck plan too big for the home?
Local building codes will dictate some of the rules about the size and design of the deck, but as a general rule of thumb, pro builders like Milanese say decks shouldn’t dwarf the largest room inside the home and shouldn’t surpass 20 percent of the home’s total interior floor space. That means the average home — which measures 2,687 square feet, according to the Census Bureau — would support a 537-square-foot deck.
When designing the deck, be sure to include measurements for deck furniture and other accessories you own or may buy, says Marlow. Think: table, chairs, grill, hot tub and planters.
“Curving deck shapes can be seductive, but they are also brutally unforgiving of errors and can quickly run up lumber costs. … Linear designs are always easier to execute.” —Chris Peterson
Once the plan is on paper, get a realistic feel for the size by outlining the deck on the ground. “Use chalk, landscaping spray paint or colored twine to create the actual silhouette of where the deck will go,” says Peterson.
Pro tip: Don’t design a curved deck unless you’re hiring an accomplished woodworker (or happen to be one). “Curving deck shapes can be seductive, but they are also brutally unforgiving of errors and can quickly run up lumber costs,” says Peterson. “Even modest angles can be a challenge. Linear designs are always easier to execute.”
How much will this deck cost?
The cost per square foot of a deck varies widely by region, contractor qualifications and rates and the price of material. HomeAdvisor estimates that a simple 200-square-foot deck will cost approximately $4,836. One way to zero in on the cost: get at least two or three estimates for labor and materials. For example, decking material alone can range from $3.50 per square foot for basic cedar to $7.50 for hollow-core PVC to $22 for the Brazilian hardwood ipe.
Consider these material details when designing a deck.
About: The most common types of wood used for decks are pressure-treated cedar, pine and redwood. Hardwoods, such as ipe or teak, are more durable (and expensive) than softwoods, like pine.
Pros: Wood is typically less expensive depending on the grade and type (basic pressure-treated wood averages $3 per square foot; at the high end, redwood can cost around $8 per square foot, uninstalled, according to Improvenet.com). Wood looks warm and wonderful, weathers handsomely and it feels great to walk on.
Cons: Most types of wood requires yearly maintenance (sanding and resealing or pressure washing) and are prone to insect and water damage, although high-quality, treated wood or hardwoods can withstand both.
About: Composite material is made from plastic (sometimes recycled) and waste wood fibers and comes in a range of prices and styles, including types with imitation wood grain and surfaces.
Pros: It’s lightweight, easy to clean and environmentally friendly. Many types of composite deck material come with a 15- to 25-year warranty.
Cons: Composite can be pricey — $25 to $70 per square foot installed, according to Realtor.com. In the sun, some materials can be hot underfoot.
About: Made from high-density plastic, these materials fall between wood and composite in pricing, from $14 to $18 per square foot installed, according to Realtor.com.
Pros: Plastic tends to resist staining and fading and is considered low maintenance because it doesn’t require sanding, staining or painting.
Cons: These materials aren’t available in a wide range of styles or colors. Also, some of them tend to lose shape over time and can be hard to clean.
“Save money by designing your deck for standard lengths of lumber — 6-, 8-, 10-, or 12-foot boards — to eliminate any wasted wood from cutoffs.” —Chris Peterson
What type of fastener will hold it all together?
Builders like Marlow say drivescrews — not nails — are a smart choice because the screw pattern is designed to “bite” into the decking and resists popping up over time. And, he recommends asking the builder or supplier to select a fastener specific to the deck material you choose.
Here’s why it matters: Pressure-treated wood contains chemicals that can corrode steel, aluminum and galvanized drivescrews. If you live near corrosive salt water or in a damp, rainy climate, hardware can rust even faster. Stainless steel fasteners may be more expensive, but withstand rust better than galvanized.
Whatever the material of the fastener, Peterson recommends using screws with 6-point star-shaped drives. “These specially designed screws have a unique ‘star’ head slot that ensures against stripping.”
Pro tip: Regular deck maintenance — power washing, sanding and resealing — can extend the life of your deck from a dozen or so years to more than 30 years, depending on the climate. “Every few years, even composite decks will need cleaning to keep them from getting too slippery from mold, mildew and algae,” says Jeff Wilson, an Ohio-based contractor with more than 25 years of experience building homes and decks.
Don’t forget about taxes
According to IRS guidelines, building a deck is a capital improvement and may increase local property taxes. Taxes vary from city to city, so check with the local tax assessor before beginning construction or repair.
Certified master home inspector Marlow says building a deck with safety and durability in mind means homeowners can really relax and enjoy the outdoor space with family and friends — or in splendid solitude. And if Marlow happens to walk by, he won’t worry about joining you on the deck.