TPI Program for Laminated Logs in Full Swing
by Mike Hoffer

The November wind carried the scent of winter through the leafless scrub oak covering the canyon's hillsides. James Grant knew snow would soon blanket his home site here in Hobble Creek Canyon near Springville, Utah. With the foundation already poured, his dream of building a log home was almost reality. All he needed was a truck to transport his laminated logs from Glu-Lam-Log's yard in Victor, Montana to his home site in Northern Utah. "That's when I learned that Utah county would not approve the logs," James says.

His logs were stacked and ready at the plant, but without a stamp on them from a certified grading agency the county building inspector would not approve James' building permit. For the first time in ten years of business, a Glu-Lam log was rejected by an inspector.

James tried to convince the Utah county building inspectors to approve his laminated logs. Glu-Lam-Log, Inc. sent him samples and "a ton of information," says Phil Alman, part owner of Glu-Lam-Log. But the inspectors would not budge. No stamp, no approval.

The program, headed by Dr. Tom Gorman, showed that "given a solid log of the same shape and size, Glu-Lam's laminated logs have a 50% higher design rating." Design stresses show how big a cross-section is necessary to handle bending loads. A copy of this test report is available from Glu-Lam-Log for the asking.

The test confirmed their belief in the structural integrity of the laminated log. Unfortunately, as James found out, a study from the University of Idaho does not meet building codes in Utah. No stamp, no approval.

James said, "What frustrated me was the fact that we all felt, including some of the inspectors, that Glu-Lam's product was a better log than what my neighbors were using to build their homes. But, because it was not stamped, it could not be approved."

The stamp the inspector wanted to see would show him that a qualified testing agency certified that the logs met specific standards of quality and would conform to the major building codes in the country. Without it he could not be sure of the log's structural integrity.

Initially, Glu-Lam was hesitant about starting the process to obtain a certification stamp. They did not know if James' problem was an isolated situation or a harbinger of things to come. And Glu-Lam had no idea what had to be done to get approval, how long it would take, and what it would cost. Besides, hundreds of houses had already been successfully built using the company's laminated logs without a single complaint about performance from a customer.

However, as each effort by James to change the Utah county inspector's decision met the same brick wall - no stamp, no approval - Glu-Lam-Log decided to contact Timber Products Inspection, Inc. (TPI). As Phil Alman explains, "By this time we were feeling awfully obligated to James for all the legwork he had done. Helping him get his home approved became a matter of company pride."

TPI is one of the larger certified testing agencies in Glu-Lam's region: they are the third party testers at mills throughout the Northwest; their regional office and laboratory are in Portland, OR; they have a local inspector who is based in Stevensville, Montana - practically in Glu-Lam-Log's back yard; and the company is familiar with logs for log homes.

By meeting TPI's requirements, Glu-Lam-Log's products would meet all of the major building codes in the United States. This would mean easier approval of permits for Glu-Lam's customers and a stamp of approval, by an unbiased party, for the laminated log's quality. Working with TPI's Quality Assurance Manager, John Elliot, Glu-Lam-Log set up a quality assurance program, which TPI requires before it will issue a stamp.

The first problem to solve was how to classify a laminated log. John and Bob talked it over and finally decided to evaluate the logs as structural beams in the L3 Structural Beam category. This required Glu-Lam's logs to meet higher standards than normally required for a house log.

"We do things to the logs we test that are so unreasonable, you would not believe it," says Phil. "It's overkill, but you have to remember we're being evaluated as a structural beam, not just as a house log."

As a first step in the process, Glu-Lam pulled log samples at random from its promotional sample racks. These samples all came from logs that were produced prior to the company's involvement with TPI. These samples were sent to TPI's test lab in Oregon for examination. The purpose of this informal testing was to see if the logs being manufactured by the company were in the ball park when it came to L3 laminating specifications. As it turns out, the samples all passed delam tests and shear tests by a wide margin. However, no formal approval could be given to these logs because they were not built under TPI quality assurance guidelines.

Having determined that the odds were pretty good that formal approval could be achieved, the next step was to specify and purchase the test equipment necessary to implement TPI's QA Program. "John gave me the list of equipment we needed and told me who made the best devices. I figured he knew a lot more about this than me so I did exactly what he recommended," says Bob. He smiles and says, "Our equipment is more high tech than the local TPI inspector's. I set everything up and called TPI to reserve a time slot for actual implementation of TPI's program."

During John's initial visit, he watched how Glu-Lam makes their logs, he demonstrated how to conduct the shear and delamination tests, which determine lamination quality. He actually witnessed production of logs and gathered samples from the logs produced to test at TPI's regional testing lab.

John returned to Portland with the samples and they passed all the tests. A stamp was issued and, as Phil says, "This was another part of the evolution of Glu-Lam-Log from a mom and pop shop to a legitimate company."

There are two types of standards that must be met when testing the laminated logs: pre-use standards and daily test standards. The pre-use standards are higher than the daily. Daily tests are conducted on each day's set of logs and the pre-use are conducted when the lamination crew uses a new batch of glue.

In keeping with Glu-Lam's stated policy of keeping the owners directly involved in the things that matter most, Bob does all the testing personally. He says it takes him about half an hour a day. He drills ten core samples from a three foot section of a new log. Then he slices the remaining wood into ten pieces that look like the samples Glu-Lam sends to customers. The cores are for the shear test and the slices are for the delamination tests.

The shear test machine operates like a metal shear. The wood is stuck into a hole, the glue lines are lined up with the ram, and a hand operated hydraulic pump applies pressure along the glue line. The shear must not occur below 790 pounds per square inch (psi). Glu-Lam's logs usually hit 1300-1500 psi before failing.

After the core snaps, Bob determines the ratio of wood failure to glue failure. A high percent of wood failure shows the glue is strong and stable. The required percentage for a daily test is 70%; the pretest is 80%; Glu-Lam averages 92% -- much more than needed.

The second daily test required by TPI determines the percentage of delamination under severe conditions. Bob measures the glue lines of the wood slices. Then, using a sealed kettle filled with water, he immerses the samples. Next, he draws a vacuum and lets the kettle sit for a specified amount of time. He then pressurizes the container to several atmospheres of pressure. The combined effect supersaturates the wood. The waterlogged wood is then placed in a convection oven, Bob cranks the heat up to 160 degrees, and the samples bake for at least ten hours. When they are done, he measures the percentage of the glue lines that delaminated.

"Even our rejects pass these tests," says Bob. "I grabbed an old log that was used as a sticker out in the yard when John Elliot showed us how to use our testing equipment. It had been outside in the rain, mud, sun, and snow for a couple of years and it passed all the tests."

In addition to the tests, Paul Morling, Glu-Lam's lamination supervisor, fills out a daily glue-up log at the beginning of the day. He records the order number and rack ID for the logs being glued, temperature and humidity of the lamination room, glue specifications, wood specifications, and glue-up rack measurements.

When the local inspector makes his monthly visit, he brings his own equipment and makes sure the daily records are accurate. He also checks the quality of wood used to make laminated logs. He was surprised by Glu-Lam's strict grading process and suggested that the lamination crew was rejecting fifty percent more wood than necessary.

Bob and Phil explain how structural integrity is only one part of the equation in the construction of their logs. The aesthetics of the log are important, too.

"We are not producing a log just for the purpose of building a solid house," says Phil, "but also to provide beauty in your home. We balance strength with beauty."

There are many benefits for Glu-Lam-Log and its customers by qualifying for TPI's stamp. With TPI's guarantee of structural integrity, Glu-Lam's customers can get projects approved more easily because their logs will meet any building code in the country. The customer also has the security of knowing these logs are made to higher standards than necessary for building a log home.

For the company, the tests help to keep better track of quality. By meeting TPI's standards every day, Glu-Lam's employees are confident that they are doing a good job and it gives them a constant goal to meet with every new batch of logs.

Bob says "Our quality program also helps TPI. Because laminated logs are a new product for them to grade, our standards are becoming their standards."

On April 3, 1995, the first logs bearing Glu-Lam-Log's TPI stamp were shipped to James Grant and his waiting foundation. Although it meant the realization of his dream for a log home would have to wait until the summer of 1995, James believes the logs were worth the wait.

"We got the quality we wanted," says James, "and the assurance that it's been certified."