Racing the clock

• Photo courtesy of Bob Carlson Inc., Hillsboro, Ore.
• Photo courtesy of Bob Carlson Inc., Hillsboro, Ore.
• Photo courtesy of Bob Carlson Inc., Hillsboro, Ore.

Kraft Foods Inc., Northfield, Ill., is well-known for its products such as cookies, crackers and, of course, macaroni and cheese. When producing mass quantities of food, a careful, selective process is followed so Kraft Foods can produce quality products.

Kraft Foods used that same scrutiny when choosing a company to remove and replace the roof system on its 330,000-square-foot (30657-m²) production facility, which is considered a landmark in Portland, Ore. Although Kraft Foods invited various contractors to bid on the project, only three roofing contractors in the area qualified.

One of those three—Bob Carlson Inc., Hillsboro, Ore.—was chosen to perform the tear-off and roof system installation.

Time constraints

From the beginning, Bob Carlson Inc. faced time challenges. Because of Kraft Foods' budget allocations, the first phase of the project—which was a roof system replacement on a 77,000-square-foot (7153-m²) area of the facility—was not able to begin until November 2004, and Bob Carlson Inc. was told the factory representatives needed 70 percent of the roof system to be complete by Jan. 1. Kraft Foods had to have the funds allocated and dispersed by Jan. 1, which gave Bob Carlson Inc. only two months to complete more than two-thirds of the project.

The time period during which the project was to take place was challenging, as well. The roofing company had to work during November and December in Portland and was almost guaranteed to face some rough weather. However, with a mild November and December and a commitment from management and field personnel to work overtime (10- to 12-hour days), weekends and holidays, Bob Carlson Inc. was able to maintain the tight schedule. And because of Kraft Foods' budget requirements, the roofing contractor was required to continue the project no matter what the weather conditions while being responsible for any interior damage or production delays.

Because the Kraft Foods facility operates 24 hours per day, seven days per week, with food production lines constantly open, significant caution with regard to interior protection was necessary. Sensitive production areas required scaffolding, plastic sheeting and rigid plastic. All protection procedures—including processes and materials—had to be approved by Kraft Foods before implementation.

A rocky road

Bob Carlson Inc. first was required to remove the existing roof system, which consisted of a two-ply vapor retarder over a structural concrete deck; 2-inch- (51-mm-) thick Fesco board; a four-ply coal-tar-pitch roof system; and pea gravel. The planned tear-off process involved vacuuming the rock, cutting the roof system with roof saws and removing the coal-tar-pitch roof system with tractors.

However, the tear-off process did not go as planned.

"As it turned out, the rock was unable to be vacuumed," says Tony Freas, project manager for Bob Carlson Inc. "The ash from the 1980 Mount St. Helens eruption still was embedded in the rock ballast on the roof. When the ash became wet with the winter rains, it created mud, which caused the vacuum hose to constantly clog. This made it impractical to use the vacuum equipment. Therefore, 154 tons (140 Mg) of rock were removed by hand. We had to use dump carts and four-wheelers to move all the new and old materials to only one staging area."

Freas says the existing slope of the roof was "dead-level," and had a significant amount of ponding water.

In addition, because minimal ground space was available, all the demolition had to be brought across the deck to one staging area. Some debris had to be carried more than 300 feet (91 m) and down eight building stories.

Installation

As Bob Carlson Inc. began to prepare for installation, the company encountered material issues.

"The materials were scheduled for delivery just before Thanksgiving, and the manufacturer was unable to secure a freight company willing to deliver before the holiday," Freas says. "Therefore, to get started, some materials were taken out of the manufacturer's local stocking warehouse."

Between six and 15 roofing workers were involved with the roof system installation. The company installed 2-inch- (51-mm-) thick Derbiboard® polyisocyanurate insulation adhered with Olybond™ 500. A Derbibase® Ultra APP-modified bitumen base sheet then was installed with Permastic® adhesive, and a Derbibase Ultra torch-applied APP-modified bitumen roof system was installed. Finally, Bob Carlson Inc. installed a Derbigum GP-FR torch-applied APP-modified bitumen roof membrane and a smooth-surfaced fire-rated cap sheet.

The company did not encounter any major fall-protection issues during the project because the facility had a built-in guardrail around the roof perimeter.

A rare experience

Kraft Foods found Bob Carlson Inc. to be the right company for the job, and gave the company full responsibility. "After the local factory hierarchy realized the professionalism of Bob Carlson Inc., they decided to remove the consulting firm from the project," Freas says. "They believed they were able to get the same quality roof at a lower budget through our abilities."

Bob Carlson Inc. was happy to have a chance to be involved with such a challenging project.

"The most rewarding thing is to accomplish a project of this complexity knowing there are few companies that can do so," Freas says. "And few companies are even given the opportunity."

Krista Reisdorf is associate editor of Professional Roofing magazine.

Project name: Kraft Foods facility
Project location: Portland, Ore.
Project duration: November 2004-March 2005
Roof system type: Torch-applied APP-modified bitumen
Roofing contractor: Bob Carlson Inc., Hillsboro, Ore.
Roofing manufacturer: Performance Roof Systems, Kansas City, Mo.