As part of an overall revitalization plan for the city of Lawrence, MA, a new, $110 million high school campus is being built, with construction expected to be completed Fall 2006. Lawrence High School’s new, state-of-the-art campus will be the largest high school ever constructed in the state of Massachusetts. The 25-acre campus will consist of six independent, career-themed “academies” that will give Lawrence’s 3,000-plus high school students the opportunity to attend a school that is specifically tailored to their future career aspirations.
Although each of the six academies of Lawrence High School will offer different curriculums, from business to performing arts, the construction of each building will be nearly identical. They will all be rectangular, 4-story buildings with brick facades. Each building is required, per Massachusetts’ most recent energy code, to have an air barrier underneath the facade that covers the entire building envelope, including all four walls, the foundation, and the roof. The code, dubbed CMR 780, is the first code in America to require an air barrier on all new, non-residential construction.
“Stopping building air leaks is critical for improving energy efficiency and for preventing moisture-related problems such as mold growth and water damage in buildings,” says Brian Carey, air and vapor manager for Carlisle Coatings & Waterproofing Inc. (CCW), whose products were used on the new Lawrence High School. “The latest energy codes and a great deal of scientific studies affirm the importance of an air-tight building envelope.”
Jobs for installing the air barriers and roofs on the Lawrence High School were put out for bids and, after review, Acme Waterproofing from Rockland, MA, was chosen to apply the air barrier to the walls and foundation. A.J. Desjardins Roofing Company Inc. from Exeter, NH, was selected to install the roof. Acme recommended installing CCW’s Barriseal™ air and vapor barrier system because of their extensive experience with this product and their confidence in CCW. Barriseal is a water-based asphalt emulsion modified with a blend of synthetic rubbers and special additives that cures to form a flexible, monolithic membrane on virtually any wall. A.J. Desjardins Roofing Company elected to install a Carlisle SynTec 60-mil reinforced Sure-Seal® EPDM roof system on all of the school’s buildings. CCW is a wholly owned subsidiary of Carlisle SynTec Inc. “The whole project is Carlisle,” says Keith Sportack, CCW representative and president of PACE Representatives.
Before the roofing membrane or Barriseal was installed, Acme applied CCW’s full line of 705 flashing products on the buildings’ windows, doors, and joints. These products were used to tie-in with the Barriseal and EPDM roof system that would be applied later. CCW’s 705 flashing products are 40-mils thick, consisting of a self-adhering rubberized asphalt membrane laminated to a 4-mil or 8-mil high-density polyethylene film. To install the flashing products, Acme used CCW’s CAV-Grip primer, an aerosol primer unique in the industry.
“Unlike traditional primers, CAV-Grip primer allows you to immediately install flashing products without having to wait for the primer to dry, or flash off. Traditional primers can take as long as half a day to dry, depending on the weather conditions,” says Sportack. Since the buildings on the high school’s campus were 4-stories tall, much of the work was done from a lift. CAV-Grip primer allowed Acme’s crew to prime and install the flashing products at the same time, without having to move the lift back and forth waiting for the primer to dry.
After all of the flashing products were installed Acme went to work applying the Barriseal directly to the buildings’ concrete-masonry-unit (CMU) structure. Most of the buildings were covered with Barriseal-S, a spray-applied form of the air and vapor barrier. Barriseal-R, the roller applied version of the product, was used for detail work where the Barriseal-S could not reach.
Because brick was installed after the Barriseal, hooks had to be placed every 2 square feet in the CMUs, tying the brick to the block. Barriseal-S has the ability to seal around any penetrating fastener, which meant Acme would not have to flash or caulk around every hook. “The most effective and easy approach to comply with Massachusetts’ law is with a Barriseal spray application,” says Sportack.
Carlisle requires minimum 40-mil thickness of the Barriseal air/vapor barrier after cure. “One pass with Barriseal-S by a skilled applicator will easily provide this thickness. Barriseal also features a co-spray system that allows the product to be applied in a wide range of temperatures. Plus, it is a solvent-free, water-based material, so it poses no fire, odor, or health hazards,” says Carey.
After the Barriseal application was complete, Acme conducted daily quality control tests to ensure the Barriseal was installed properly. Acme performed a pull test (per ASTM D 4541) to make certain the Barriseal was adhered to the substrate properly, and they also performed an air bubble test (per ASTM E 1186) to check for air leaks within the system. According to Acme, everything checked out fine.
Carlisle's EPDM roofing systems were installed on the six buildings. Half of the buildings had 22-gauge steel decks and the other half had concrete decks. For the buildings with steel decks, Desjardins' crews installed Griffolyn® TX-1200® FR, a 3-ply laminate used as a vapor retarder on the roof. The Griffolyn, which features a seam tape, tied the roof system to CCW's 705 flashing on the parapets. After the Griffolyn, Desjardins mechanically fastened two layers of 1.5-inch-thick polyisocyanurate insulation followed by a layer of quarter-inch-thick Georgia Pacific Dens-Deck Prime. Then, Carlisle's 60-mil non-reinforced EPDM was fully adhered to the Dens-Deck Prime using Carlisle's 90-8-30A bonding adhesive.
The Acme representatives say transition from the wall to the roof is essential for creating an air and watertight system because that’s where the potential for leaks is the greatest. They use Carlisle products because they know the two systems will be compatible.
For the buildings with concrete decks, Desjardins hot-mopped a 30-pound felt to the deck directly over the CCW 705 flashing, again tying the roof system to the walls. After the felt was down, Desjardins installed tapered polyisocyanurate insulation because the buildings were made from pre-manufactured concrete planks that had to sit level so the joints could be grouted. The tapered polyisocyanurate was topped with quarter-inch-thick Georgia Pacific Dens-Deck Prime followed by the fully adhered 60-mil non-reinforced EPDM.
“These buildings are completely air- and water-proof. You could sink them in water and they wouldn’t leak,” says Al Desjardins, owner of A.J. Desjardins Roofing.
As building codes begin to conform to the standards set by Massachusetts, building owners and facilities managers around the country will be required to specify quality air and vapor barrier systems for the construction of their new buildings. Only Carlisle SynTec and its business segment CCW can provide an air- and vapor-proof system, coupled with industry-leading warranties, administered from one company.