A sparse exterior on a Dunwoody home built in the 1950s opened the door for Brannen Development Co. to add a deck and expand the home’s outdoor space.

The 12-by-20-foot deck was going to be visible when driving up to the house on a shaded lot, so Art Brannen chose black steel roads instead of wood baluster and curved the three steps leading to the deck.

“It dressed up the deck,” he said.

The project cost about $4,000 including labor, said Brannen, whose renovations to the home (listed for $339,000) also included replacing windows and doors with insulated glass, changing the floor plan, and adding a new roof and driveway.

As aging decks start to look tired or as homeowners and sellers try to increase the value and appeal of their property, decks get attention.

More than 40 million wood decks in the U.S. are at least 20 years old, according to the Pennsylvania-based North American Deck and Railing Association. The American Society of Home Inspectors, based in Des Plains, Ill., recommends that decks be inspected at least every three years, since wear and tear could impact their safety.

Georgia’s hot, humid environment can be tough on wood decks, causing the need for regular cleaning, staining and sealing.

“There’s a whole lot of re-facing or re-surfacing decks. Then people are saying, ‘If I’m going to resurface the deck, then I should increase its size,’ ” said Geoff Case, a lumber merchant for The Home Depot.

Resurfacing the deck involves tearing off the existing deck boards and the railing, if needed, and could be handled by an experienced do-it-yourselfer, Case said. Building or adding onto a deck is a bigger project for experienced DIYers or professionals. Deck updates typically cost $10,000-$15,000, he estimates.

When building, expanding or repairing a deck, American Society of Home Inspectors recommends:

• Railings: Make railings between 36 to 42 inches high and use vertical rails for safety.

• Structural joints: Use bolts instead of nails to securely fasten decks to the adjacent building.

• Joist systems: Use steel supports and ties to install the support structure.

To start a deck project, think about what you like and don’t like about the existing outdoor living space, Case said

“Invariably what we hear from customers a lot of times, especially here, is, ‘I don’t like how much maintenance it takes,’ ” Case said. “Products out there today require less maintenance, not no maintenance, but less maintenance. I always tell customers I can’t think of anything left outside that requires zero maintenance.”

In the Dunwoody renovation, Brannen said aluminum caps were placed on all the posts for aesthetics and longer life.

Composite decking and railing materials, by companies such as Trex, TimberTech and Veranda Decking, come with warranties against warping, cracking, staining and splitting. Composite decking is more expensive, such as 75 cents per linear foot for a 5/4 premium wood deck board and $2.25 per linear foot for capped composite decking, but Case said composite materials can save money in the long run because they don’t need to be re-stained.

The different colors in composite materials allow homeowners to “picture frame” the deck by using one color around the boarder and a different color in the middle, Case said. Railings also can be changed out, with metal balusters and cable rails instead of wood.

“You can make your deck look different than the neighbors,” Case said.