Cameron Sperance -- Boston.com correspondent

Everyone likes to point to the “good ol’ days’’ for almost everything, but the latest example can save a life.

Fire experts say some residential construction practices used today are a quantum leap backward when it comes to safety.

“If you asked me the question of would I live in one of these buildings — No, I would not,’’ said Glenn Corbett, an associate professor of fire science at the John Jay College of Criminal Justice in New York City and an editor for the trade publication Fire Engineering. “I wouldn’t go anywhere near it because I know what the problems are, and, the thing is, most of the public has no idea.’’

Some residential buildings aren’t built with the same raw materials they once were, and fire experts like Corbett caution that the push for lower prices comes at the expense of safety. Soaring costs and a dwindling labor pool in recent years pushed the building industry to use more affordable materials and newer techniques to avoid drawn-out construction timelines that only added to the price tag.

These approaches to building include everything from modular and prefabricated designs — those largely manufactured off-site and then assembled at the construction site — to engineered wood, a range of lumber products increasingly used for things like joists, beams, and tresses to offset typically higher steel prices. Engineered wood, or mass timber, is manufactured by assembling various wood particles or pieces with an adhesive that creates a composite material.

“What used to be a two-by-twelve piece of sawn lumber that we knew could hold a certain amount of strength of weight and acted a certain way in fire conditions, we can build cheaper now by using trusses or engineered wood,’’ said Kevin Gallagher, Acushnet’s fire chief. “Some of the engineered wood is really just chips of wood glued together. It doesn’t work the same as a two-by-twelve or a two-by-sixteen of genuine wood, so that move toward these lightweight construction materials has been a concern for the fire service for years.’’

Engineered wood flooring, which is typically lightweight and manufactured, also raises concerns with firefighting teams. A traditional wood floor typically lasts a half-hour during a fire “until failure,’’ Corbett said, but engineered wood flooring can collapse in as little as six minutes. “There’s no fire resistance whatsoever,’’ he said.

This quicker fire failure often stems from “I-beams’’ when a thin piece of engineered plywood is placed between two wood pieces. This kind of assembly has its selling points: wooden I-beam flooring has less of a likelihood of buckling or warping than a floor made entirely of dimensional lumber (like a 2-by-4 of solid wood) and is generally quieter. But it also has a greater chance of structural failure when directly exposed to fire, fire officials said.

Steel construction is still an option but a rare one — 91 percent of the homes built in the United States in 2020 were wood-framed, according to a National Association of Home Builders analysis of Census Bureau data. Concrete framing accounted for 8 percent, while steel-framed homes took up the remaining 1 percent.

Modular and prefabricated construction techniques, deployed on a variety of commercial buildings and homes across Greater Boston, also garner concerns from fire safety officials. Modular homes are often built with spaces of more than 20 inches between the floors, providing a way for fires to spread quickly in a similar fashion to balloon-framed structures.

“Void spaces are bad because fire gets in there, and you often can’t find it until it’s too late,’’ said Jerry Knapp, a veteran firefighter and training officer at the Rockland County Fire Training Center in Pomona, N.Y.

But the construction industry continues to see this kind of building method as a way to cut costs, labor, and delivery time — so much so that developers are literally taking the practice to new heights.

The International Code Council, which largely informs state and municipal building codes across the United States, approved a change to its 2021 International Building Code allowing mass timber construction of up to 18 stories.

Corbett cautions against such a building technique, calling these structures “toothpick towers.’’

“Introduce several of these into a downtown area like Boston, and you’ve got yourself into a modern equivalent of the Great Fire of 1872,’’ he said. “It’s a different era with different construction, but these things, when they go up, they’re one heck of a problem when they’re built into a tight, city-congested area. This is another reason we don’t want them. But we’re ignored.’’

The ninth and most recent edition of the Massachusetts Building Code relies on the 2015 edition of the International Building Code, which caps wood-frame construction at six stories. But even that has garnered a wave of safety concerns among the firefighting community.

A 2015 New Jersey fire at an apartment complex owned by AvalonBay Communities, the real estate investment trust behind numerous residential developments in New England, raised eyebrows given that a different wood-framed development under construction on the site also caught fire 15 years earlier.

AvalonBay’s Fire Elimination Program includes sensors across a construction site to broadcast data to the development team on hazards like freezing temperatures and fire risks, according to Scott Kinter, senior vice president of construction at AvalonBay Communities.

“Fire is always a concern with any building, whether it’s a wood-framed building or a building constructed of steel and concrete, until the building is fully protected with an automatic sprinkler system,’’ Kinter added. “This system typically isn’t live until you have drywall installed as well as the permanent heat functioning, and this is why we employ such a robust fire elimination program.’’

Locally, two 2017 fires at wood-framed apartment construction sites in Waltham and Dorchester garnered scrutiny around the building practice given the vulnerability prior to completing construction.

The Globe reached out to the City of Boston’s Inspectional Services Department about the increase in these building techniques. The city deferred to the state, which is in charge of updating the building code “every few years’’ via the Board of Building Regulations and Standards, according to a spokesperson for that board. Only two of the 15 member seats are required to be held by individuals from the firefighting community.

The Massachusetts chapter of the Associated Builders and Contractors trade organization — billed as the largest of its kind in the state — pushed back on the idea that residential construction has turned into some kind of lawless, unregulated entity just because builders are relying more on wood construction and faster construction techniques like modular.

“You can never say that everything is going to be without safety issues or concerns, but it would certainly be fair to say that built into the amount of oversight we have here, there’s a strong safety component that is also interwoven,’’ said Greg Beeman, president and CEO of the Massachusetts chapter of the organization. “It will be hard to have a Wild West kind of scenario unfold here with the framework we have in place.’’

The leaders of the National Association of Home Builders, as well as its Massachusetts chapter, say some of the fire concern is overblown and just happens to coincide with the proposed “An Act Relative to Safe Building Materials’’ legislation before the Massachusetts Legislature.

“We could probably all construct a house that would withstand virtually any fire event, any wind event, and any flood event that God or man could create. The problem is no one could afford to live in it,’’ said Jerry Howard, National Association of Home Builders CEO. “You also have to take into account affordability, and when you balance those things together and look at where we are right now, I think the system has worked very, very well.’’

The proposed bill, inspired by the wood-framed multifamily construction site fires, calls for a tougher building code with respect to lightweight wood projects and heightened fire safety with measures like more sprinklers, fire blocks, and a cap on wood-framed construction at four stories. The last point comes as the board considers incorporating the higher height allowance for wood-frame construction enabled by the ICC’s 2021 code.

Building trade groups argue that the bill would send construction costs even higher for issues they see as isolated incidents getting overblown by headlines. Joe Landers, executive officer of the Home Builders & Remodelers Association of Massachusetts, agrees that fire departments have valid concerns about modular homes when it comes to how they are often inspected by a third-party inspector at the factory where the parts are assembled rather than at the building site by a local inspector.

“Both the fire department and the local building officials have been critical of the way the modular industry provides product,’’ Landers said. “[Most] of the inspections of modular products take place by third-party inspectors in the manufacturing facility and not on the site. And that has certainly rankled a few feathers regarding the local building and fire officials.’’

But Landers also doesn’t see a need for wide-ranging new regulations when it comes to fire safety and how more homes are getting built.

“Our association is certainly concerned about safety and concerned about the environment, but we’re also concerned that the residents of Massachusetts deserve to be able to, at some point in their lives, get into a single-family home if they so choose,’’ he said. “We just keep moving the ball further and further away for a lot of people to be able to afford single-family homes.’’

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