These days, outdoor rooms are all the rage with young and old alike. But the installations required to make these dream rooms become a reality can challenge even veteran window contractors.

“There’s nothing like having a large 16-foot opening to the outdoors,” said Phil Isaacs president of California Energy Consultant Services. “But it can still be a little bit of a gear up every time you do one.” And the less experience contractors have, the more they need to gear up, he added.

While the outdoor living trend started in the warmer climes of California and Florida, experts say it’s they’re just as popular in areas of the country such as Minnesota.

Nationwide, outdoor rooms are particularly popular among hard-to-please millennials, according to several surveys published in the Washington Post:

-- Outdoor living space was the no. 1 “must have” among millennials who are homeowners or actively looking for a house, according to a recent survey by TRI Pointe Group, the parent company of Pardee Homes.

-- Similarly, the top must-haves for millennial homeowners and buyers included a patio, front porch and a deck, according to The National Association of Home Builders.

-- 71 percent of millennial-aged female homeowners characterize outdoor space as an important area for their family to spend time together; and 70 percent use it for entertaining, says a Better Homes and Gardens survey.

Here’s a look at four types of installations contractors use to add outdoor room expansiveness to a home:

  1. Sliding glass walls. As the name suggests, these installations consist of sliding glass walls — similar to their less sexy cousins, sliding doors — that stack at one or both ends of the opening, leaving a large expanse completely open to the outdoors. The larger glass doors allow for a panoramic view when open or closed. They also tend to be slightly less expensive than bi-fold doors, Isaacs says.
  2. Bi-fold doors. These doors work much like the typical accordion closet doors found in some homes but with much more sophistication and beauty. With bi-fold doors, the glass panels fold into themselves. These systems can either fold doors into one side or both sides. Some systems allow the folded doors to be completely pushed out of the way. Isaacs says these systems can be more “temperamental” than sliding glass systems.
  3. Multiple French doors. Using more than one French door in close succession or without any break is a more traditional — and often less costly — way to blur the lines between inside and out. But unlike the previous two options, the doors don’t disappear.
  4. Picture windows. For some homeowners, the tried and true picture window is still the best way to bring the outdoors inside. These are typically combined with a simple glass door or sliding door to the outside. They can be one of the least expensive options.

No matter which installation option your customer chooses, these wider openings require more care than typical two or even three door openings — and they’re much more expensive.

“The additional construction required can turn a job that’s a couple thousand dollars into a job that could cost tens of thousands of dollars,” warns Stephanie Vanderbilt, owner of Coastal Windows & Exteriors. “So it’s critical for homeowners to know exactly what they are getting into.”

Even if you make the sale, the biggest challenge — removing entire walls — is yet to come. “Most likely, there will have to be a steel beam header running across the home to ensure the existing structure will be able to handle such a drastic change to its support systems,” said Vanderbilt. “So engineering is a must on these types of projects.”

Some of the most dramatic outdoor rooms feature a corner entry, which raises even more engineering issues, such as sheering, Isaacs. Either way, most jurisdictions require such projects to employ the help of a professional engineer.

And that’s often just the start of the extra costs — and headaches — that can arise when cutting into existing walls. For example, electrical and plumbing are often embedded in walls, even when they’re not expected to be there. “You don’t really know what’s inside a wall until you open up,” Isaacs said.

The same uncertainty can be true of the moving glass systems themselves, especially for contractors who don’t do a lot of them. “Understand they are not easy to install, so do your homework before jumping in,” said John Gorman, president of Save Energy Company.

Isaacs recommends working with the manufacturer to train head installers and keeping reps at the ready for any problems that crop up along the way. He also says it’s smart to set customer expectations about the project.

“There’s nothing wrong with letting the customer know that your tech has 25 years of experience, but this is the first moving glass wall system from this vendor,” he said. “Then you tell them, ‘We’re going to get it right. But heads up, we may have to call in for a rescue with customer service.’”