Whether a hotel is in a bustling downtown area or right next to an airport runway, designers and suppliers are finding ways to make sure that a guest’s stay is as quiet as possible.
Soundproofing has to be considered from the very beginnings of any kind of new-build or renovation project. For example, atrium-style hotels can act as giant echo chambers, bringing noise from the lobby up to the penthouse suite. “You have to think about the inside walls like they’re on the outside,” Scott Rosenberg, president of Jonathan Nehmer + Associates and principal with HVS Design, said about this style of hotel.
Determining what part of a hotel goes where is also important for keeping sounds in the right places, Rosenberg said. Putting a gym or spa in between the public spaces and the guestrooms helps prevent noise from traveling up—but only if the walls and ceilings are properly insulated. “What does it sound like when the weights hit the ground?” he asked rhetorically. While people in the lobby may not notice the sounds of a workout above, meeting attendees in the function spaces might.
Building the Bones
The initial construction also plays a major part in soundproofing. Concrete subfloors in newer hotels help prevent sound transfer between levels, but older hotels may have wood or plywood floors that can creak. Hardwood or luxury vinyl tile flooring that sits on top of this flooring will not help dampen the sound. In fact, it can make the situation worse. “If the subfloor is not sturdy enough, if it's not flat, if it's not secured properly, the flooring will move and there will be a sound from that,” said Allan Singh, general manager of North America for Havwoods International. To prevent this, Singh recommends gluing down whatever overlay is on top of the subflooring rather than “floating” the floor—that is, not nailing or gluing the material down. “If you have a sturdy subfloor and your product is glued down, then that flooring then becomes part of that subfloor's structural integrity and it minimizes the movement,” he said. Minimizing the movement minimizes the sound transfer.
Adding a substrate can also help keep sound isolated to one space, and Singh recommends cork or rubber for this purpose. Polystyrene substrates, he said, disintegrate over time and will need to be replaced, requiring a significant renovation.
Stonehill Taylor senior interiors associate Sara Duffy, who is helping build the upcoming TWA Hotel at New York City’s John F. Kennedy International Airport, said that the team was installing luxury vinyl tile flooring in all the guestrooms in order to keep sound from traveling between floors. “LVT itself is a sound-absorbing material because it's quite soft, and then under that is an underlayment that we'll apply,” she said.
Keeping Sound Inside
Once the floors are in place, the windows play a significant role in keeping outside noise from getting in. In fact, Randy Brown, president of Soundproof Windows, said a properly installed window can be quieter than the walls. The difference, he said, is in the amount of air between the panes of glass because empty air does not transfer noise like material things can. “The existing windows stop a moderate amount of noise when you create an airspace between it and a good acoustic window,” he said. “The weight and the thickness of the glass all add up to stop more noise.” With 2 to 4 inches in between each pane of glass, Brown said, the noise reduction is “substantial,” but after 6 inches the differences become marginal.
The width of each pane of glass also factors into the noise reduction, Brown added. General noise can be handled by quarter-inch laminated glass, while substantial noise (say, from a concert by the hotel pool) can be dampened with three-eighths-inch laminated glass. For extreme noise like nearby trains and jet engines, five-eighths-inch laminated glass is best. “Which category depends on the noise problem and the budget,” Brown said, noting that the thickest glass was about 25 percent more expensive than the quarter-inch version.
When the TWA Hotel opens next year, it will include several design elements designed to keep the sound of jet engines outside. The 5-inch glass facade of the hotel is ordinary glass, said Tyler Morse, CEO of MCR and Morse Development, but the engineering of the material is unique, with three pieces of glass laminated together, then an air gap, then two pieces of glass laminated together, then another air gap, and another two pieces laminated together. The air gaps, said Morse, are what deaden the frequencies. All of the pieces of glass—and those gaps—are less than 5 inches thick, but have proven very effective. The company tested the curtain wall in York, Pa., where it got a Sound Transmission Class rating of nearly 50.
While flooring and windows are the major factors in keeping a hotel quiet, small details can make a big difference. For example, Rosenberg said, guests in one room often can hear the TV in another if the TV is installed on the wall. Instead, he recommends having millwork close to the wall and installing the TV on that instead, creating a solid barrier between the unit and the next room. “Some owners say, ‘Let’s just put it back on the dresser!’” he said.
Duffy agreed, noting that having TVs back-to-back in two different rooms can also cause problems. Electrical outlets—essentially holes in the wall—present similar challenges. “We always stagger them so that there isn't that sound transmission issue,” she said. “Even better is if you stagger them through stud bays, meaning that instead of just staggering them 2 inches apart, you actually want to move it to the next stud bay so that the transmission doesn't come through.”
Due to safety codes, all main guestroom doors must have a small space underneath, but hoteliers can install a brush or sound gasket. “When your door closes, that releases underneath and falls to the floor and creates a sound barrier,” Duffy said.
The amount of money a hotel invests in soundproofing should depend on how long a guest will be staying. “If the typical length of stay is one night, then they're going to be less worried about it,” Duffy said. Guests spending a week at a resort, however, will be much more irritated if they are awakened several nights in a row—and much less likely to recommend the property to future guests.