Unitized and Pre-Fabrication Find their Place on More Jobsites

By Ellen Rogers

If you had to describe the perfect glazing project experience, from start to finish, how many of these items would you like to include?
• Being on schedule;
• Staying on budget;
• Productive meetings;
• Ample labor;
• A safe and healthy jobsite;
• High-quality materials;
• Minimal jobsite waste;
• Perfect weather.

Besides the weather and maybe the productive meetings, having all of these might seem impossible. But there’s a construction trend that might help you check off all the boxes: pre-fabrication.

In the glazing field, unitized curtainwall may come to mind first. It is pre-fabricated, meaning the systems are built in the shop and installed on-site. This process requires less labor, improves quality control and means a safer work environment.

Those benefits are just some reasons why unitized curtainwall is growing in demand. According to Key Media & Research, parent company of USGlass magazine, the share of curtainwall projects that are unitized has more than doubled from 2017 to 2022. When accounting for projects to be completed in 2022 and 2023, glazing contractors report that more than one-third of their curtainwall projects are unitized.

Unitized curtainwall, however, is just the beginning. Companies are looking to pre-fabrication more to help streamline and improve their overall process. These projects have a lot to offer the glazing trade and the entire project team.

Curtainwall Basics

Before discussing where the industry might be going, let’s remember where we’ve been. When talking about curtainwall, we typically think about stick-built or unitized. With a stick-built system, the curtainwall frame and glass are installed piece by piece on the jobsite. With a unitized system, the curtainwall is assembled and glazed in the shop, then shipped to the jobsite for installation.

Ray Crawford, president of Crawford-Tracey in Deerfield Beach, Fla., says his company has worked with unitized systems since the mid-1960s. “We haven’t used stick built in 30 years,” says Crawford. He says there are several advantages of unitized construction. Quality control is one of the biggest benefits of unitization.

“There can be some quality control issues in the field,” says Crawford. “You can have contamination from dust and debris as well as environmental issues.”

He adds that working with unitized materials requires less labor than a stick-built system, and the job is less cumbersome, but labor challenges are still an issue. “We’re having difficulties getting shop personnel as much as field. However, in the shop, you can glaze faster than in the field. Unitized allows that.”

Tim Thomas, president of Erie Architectural Products, which has U.S. offices based in Novi, Mich., agrees that labor issues are a challenge for everyone.

“The biggest issue for the construction industry is skilled labor, and that’s what’s driving the unitization of everything,” he says. “We do as much as possible so the customer can reduce jobsite labor.”

And it’s not just glass. Thomas says they’re being asked to glaze in various façade materials, including metal panels, terracotta, etc.

He adds, “This is definitely a growing market, and we see that the ability to glaze in other materials will continue.”

Sneh Kumar, who handles product management and marketing for Arconic’s Building and Construction business based in Atlanta, says unitized systems comprise a large part of his company’s portfolio and offer many benefits.

“There’s less work to do on site, so that saves time. And from a sustainability view, unitized creates less waste on-site, so it’s more efficient. You also have better product quality because you’re doing the assembly in the shop, which is a controlled environment.”

In addition to unitized curtainwall, Kumar says semi-unitized is another option. He explains that semi-unitized curtainwalls are those where field labor needed to install the materials is in between unitized (minimal on-site labor) and stick-built (maximum on-site labor).

“Screw spline construction curtainwall can be built into frame-ladders in the shop, which hastens the on-site installation. Such products can also be pre-glazed, further speeding up the site installation,” he says. “Additionally, inside-glazed curtainwall does not require exterior access and scaffolding for site construction and installation..”

Driving Change

Unitization has helped make curtainwall installation cost-effective and efficient with better quality control than stick-built installation. The overall installed cost of unitized typically is higher than stick built. However, depending on market conditions, that cost might not be an issue. That’s because labor costs vary greatly city by city.

“The labor market conditions often drive the decision to go that route,” says Kumar.

Unitized curtainwall is just the beginning. Some projects now involve installing the glazing into a precast wall panel and installing the entire panel on the jobsite.

“The whole industry is still in early stages of [modular/pre-fabrication],” says Kumar, explaining that a lot of education is still needed. His company has worked on projects that didn’t start as modular or pre-fabrication, but as the building team learned more about the benefits and advantages, they made the change, he adds.

Crawford says his company is doing projects where they are working directly with other trades to pre-fabricate the systems.

“We’re doing projects where we ship the glazed units to the precast, exterior insulating finishing system (EIFS) facilities or other panel manufacturer. We go there for installation and caulking into the precast or EIFS. Then, when they deliver and erect in the field, the glazing is already done.”

“The whole industry is seeing this shift, and it’s helping combine different trades,” says Kumar. “We are partnering with precast companies where they are pre-installing windows to reduce the installation time. It’s the same with metal walls. Our windows can go in those walls. You still have to do testing and ensure the people are qualified and trained. You could have a project with a hotel wall that already has the windows installed and ready to go. It’s a route to market that didn’t exist before, and it helps the general contractor finish the job much faster.”

Need to Know

If the industry is shifting toward pre-fabrication, what will that mean for the glazing contractors?

“They will see more pre-assembled products on the site. It means they will do more installation than assembly,” says Kumar. “There will be lots more work in the factory.”

However, this trend doesn’t mean an end to traditional unitized or stick-built projects. That’s because not every project can or should be unitized.

“Stick-built construction won’t go away. Unitized and pre-glazed system use is growing, but stick-built won’t go away,” says Kumar. “If it is unique and non-repetitive, stick built, or semi-unitized is probably better.”

While stick-built might be better for highly custom and complex projects, Crawford says his company has used unitized systems in such applications.

“We have done numerous geometric projects with alternating planes of glazing and different shapes. By pre-glazing, it makes it much more efficient,” he says. “Some projects have extremely large panels. We’ve worked with unitized panels with 10.5 by 14 singles lites of laminated, insulating, laminated glass. That gets extremely heavy. Trying to do that
stick built is a recipe for disaster.”

From Windows to Walls

Unitized, pre-fabricated, modular, off-site construction … whatever you call it, this is a construction trend here to stay.

“Unitized and pre-construction work is the trend we are seeing. It’s not going to slow,” says Kumar. “The question is how fast will it grow?”

And there are a lot of good reasons for it, especially given the lack of labor the construction industry is facing.

Ellen Rogers is the editor of USGlass magazine. Follow her on Twitter @USGlass and like USGlass on Facebook to receive updates.

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