NJIT Tests Home Siding Methods for Climate Change

A centuries-old method of sealing the gap between home siding and exterior walls may soon be back in vogue, this time with an energy-efficiency slant, experts from NJIT and the BASF Corp. said last week.

Residential siding is typically replaced just once every 25 years, but the new approach uses existing and more efficient commercial installation technology for just a little more money than conventional ways. Now is a critical time to switch techniques due to climate change and the cost of home energy bills, explained Christine Liaukus, housing and community development manager at the Center for Building Knowledge, based in the J. Robert and Barbara A. Hillier College of Architecture and Design. 

"There are about 1.2 million siding jobs done in the U.S. every year," Liaukus said. "If they are done the conventional way, the inefficiencies will be locked in for 25 years that we don't have. We want to get in there now and improve the performance of these homes."

Builders refer to the seal as flashing. Tar was used starting in the 1600s, then metal, and now most contractors use tape. The new way uses a BASF product called MaxFlash, which is being renamed HP+ Flash for home use. It's a caulk-like liquid that solidifies, not unlike tar methods of the past. It costs about the same as today's high-end tapes, however unlike tape it lends itself to unique shapes versus only flat areas and square openings, a BASF official said.

Liaukus calls her project Re-Side Right. She received a $500,000 grant from the U.S. Department of Energy Building America program. The funds will pay for the center's time in partnership with the United Way to find the right homeowners and homes for testing. It will also cover the cost of training contractors; conducting before-and-after testing using technology such as infrared heat cameras; performing energy modeling in software; evaluating the real and projected impact; and producing a final report.

College of Architecture and Design students who'll work on the project will be selected soon. "We have some students here that worked as interns and I mentioned it to them. They were excited about it," Liaukus said. Her primary role is to lead the center, but she occasionally serves as an adjunct professor too. "Every class I teach, I bring students out to a job site and they are always exited about it," with student success being measured by their enthusiasm and discussions, not through traditional grades. "My belief is if they have a good awareness of building science, they're going to be much better architects, and that is truly a success story," she said.

Liaukus acknowledged it won't be easy to convince ordinary homeowners to spend a little more money for potential savings later. Lessons can be learned from recent industry efforts to market anything from hybrid cars to solar panels. "There's always the battle of first-cost justification when you're trying to have people do things to make their buildings perform better. Making those numbers work and presenting it in a way to make homeowners feel compelled to do things is going to be a challenge," she said.

As explained at the BASF website, the liquid flashing is "a one-component elastomeric material for use as a flexible waterproof flashing membrane at rough openings. It can also be used to prepare sheathing joints for subsequent application of BASF air/water-resistive barrier membranes, or for use with water-resistive gypsum sheathing. The product is compatible with damp substrates and can withstand immediate rainfall. Because the product cures quickly, it allows contractors to install windows within hours of application. This makes it ideal for new construction and restoration projects, which involve flashing rough openings," it states. "MaxFlash can be used on its own or as part of a BASF Exterior Insulation and Finish System."

Liaukus refers to her philosophy as opportunistic retrofit. It picks up where a 2012 project called Re-Side Tight, Ventilate Right left off. The technology involved back then was a form of air barrier between siding and walls to reduce particle infiltration. Continuing her theme of retrofitting existing homes, she's already starting to write the proposal for a third project focusing on cost-effective ways to improve window efficiency if contractors had only seven days to work, which is a challenge issued by DOE officials.

Existing products that could inspire such research include a window technology based on glass similar to smartphone screens from Alpen High Performance Products, along with a foam surround for storm windows from Brinc Building Products. As for BASF, product manager Joel May said his team anticipates that contractors will take 5-10 years to embrace the new approach, and that one day flashing will become obsolete as a separate product category when walls and windows are installed by robots. Laborers will become technicians. 

"Everybody is excited about energy efficiency and new construction, but the game is in existing buildings," Liaukus observed. "If we don't impact that, we're toast."