PHENOLIC INSULATION CASE STUDY

Precast Concrete Company Sets High Standards for Its Own Office

Photos courtesy of Kingspan Insulation LLC

Project Name: Stubbe’s Headquarters Building
Location: Harley, Ontario, Canada
Building Type: Commercial Office Building
Precaster: Stubbe’s Precast

The Project: Ontario-based Stubbe’s Precast Commercial is a provider of structural and architectural precast concrete, readymix concrete, and bulk cement. The new Stubbe’s headquarters is a total precast structure with three stories and a basement, built for a 120-person capacity. Stubbe’s acted as its own engineer of record and precast engineer, and the project involved exterior insulated precast sandwich panels, precast interior walls, hollow-core planks, double-tee stairs and landings, and precast beams. The building has two wings and a center atrium including a glass-encased boardroom.

The Challenge: Energy conservation in this Canadian climate was important to Stubbe’s in order to control operating costs. The need was clear, therefore, for incorporating effective building insulation that could help in that regard by keeping its energy bills in check. Achieving this can be harder in precast and tilt-up construction because the typical approach of sandwiching the insulation between concrete on either side brings its own structural and other challenges, particularly as the thickness of the insulation increases. Hence, the company wanted an R-value of R-32 in its precast panels but needed to achieve that in only 4 inches of insulation thickness. It was also aware of the concern with fire igniting insulation and causing harm to people or the building. And since it would be installing the insulation with its own workers, it was sensitive to the health aspects of handling insulation that can cause irritation as with fiber-based insulation.

The Solution: Stubbe’s was introduced to a newly formulated type of phenolic insulation that had been used in Europe for quite some time but was made available in the United States in 2017. In particular, on one of its contracted projects, it had used a version of this rigid thermoset phenolic insulation intended specifically for tilt-up and precast walls, providing contractors with higher-performance and smaller-dimension insulation materials. The availability in standard sizes or custom lengths was appealing, but so were the R-values ranging from 13.5 to 40 with an R-value of 17 over 2 inches. In addition to its superior insulation properties, the phenolic insulation provided a fiber-free rigid insulation core that resists moisture as well as water vapor ingress. It also exhibits excellent fire performance with no ignition and negligible smoke development when tested.

The phenolic insulation’s high R-value, environmental features and outstanding fire and smoke performance caught the attention of Stubbe’s management as it was designing and building its own building. Stubbe’s Project Manager Albert Meyer notes, “Phenolic insulation really worked well for us, primarily because it provides a high R-value in less thickness.” He observes that the phenolic insulation provided an R-value of 34 in only 4 inches, while most other insulation would only be about R-20 in the same 4-inch thickness since they are rated effectively at an R-value of 5 per inch. Meyer continues, “It provides better insulation, which lowers heating costs and lowers overall overhead for the lifespan of the building.”

The Results: Tom Macro, an independent sales representative for insulation products, anticipates Stubbe’s doing many more phenolic insulation based precast sandwich panels. He notes, “This rigid thermoset phenolic insulation has a fiber-free core, and its fire performance is a huge feature of the product that was really important to Stubbe’s. It also has a closed-cell structure, so it resists moisture and water vapor ingress, is resistant to fungi, and very stable. All of this is very important to precasters because it doesn’t reduce the R-value over time.” In regards to how others view it, he says, “Phenolic insulation has a low pollution potential and hits all the environmental hot points, which architects really like. R-value requirements in North America are increasing, especially in the northern climate zones, and that means thicker and thicker insulation boards, but phenolic can really reduce that thickness.”

EXPANSION JOINT INSTALLATION BEST PRACTICES

Images courtesy of Inpro

The Issue: Well-designed expansion joint products are available, but the nature of expansion joints is that they need to interface with other materials. Those other materials are most likely provided and installed by other trades.

The Solution: Following best practices as determined by addressing critical common failure points. The two most common points where thermal, moisture, and air failures occur along expansion joints are along the concrete block-out or when tying in with other systems such as roofing.

Concrete Block-outs: Block-outs are the recess in the concrete floor structure or constructed wall system that is formed by the contractor to receive the expansion joint system. Block-outs are created so there is smooth transition across the joint to allow alignment of adjacent finished surfaces. (Note that alternative regional terminology might refer to a block-out as a rebate, a knockout, or a cutout—they are all the same thing.)

There are a number of concrete related issues that come into play here. Dimensional variability in the concrete pour can lead to difficulties in installing the expansion joint framing and any waterproofing. Cold joints, that is, the regular gaps that occur with the sequential pouring of concrete, create gaps where leaks can occur when water is introduced. Other issues such as micro-cracks, honeycombing, spalling, form marks, and voids can all occur when concrete is poured and finished. Concrete all by itself is simply not watertight, and leaks will occur, sometimes by something as simple as capillary action.

Understanding the concrete issues above, it should not be surprising to learn that expansion joints can account for up to 70 percent of the contractor callbacks when dealing with this scope of work. In the experience of expansion joint suppliers, when a contractor says, “The joint is leaking,” in a vast majority of cases, failures or anomalies in the block-out or vertical substrates are the culprits, not the joint system.

Tying in Work of Other Trades: Expansion joints don’t exists by themselves; they must be tied in to adjacent construction systems installed by other trades. Besides concrete as discussed above, this can include wood framing, steel decking, steel studs and joists, exterior finish systems, masonry, and even glazing systems. The challenge—and frankly, a potential failure point—is the reliance on the skilled craftsmen and women to tie their particular installation into adjacent materials and systems well. For instance, if the glazing specification and bid documents allow the glazing contractor to simply install the frame and glass—and doesn’t demand tie in to say an adjacent waterproof vertical expansion joint—it invites problems. The same thing works the other way too: if a waterproofing contractor installs the expansion joint system and doesn’t tie into the window glazing, the seal is not complete.

While vertical tie-ins are important, nowhere is this process more important than in roofs. For obvious reasons, these large horizontal areas are going to “catch” the most moisture in the form of rain and snow. The first thing to recognize is that waterproof roofing membranes come in two standard forms. The first is fluid-applied waterproofing assemblies, such as hot mopped asphalt, torched felt/ asphaltic layers, cold-applied fluid adhesives, petroleum-based built-up systems/ SBS, and modified bitumen (MB) asphaltic with SBS modifiers. The other type is a thermoplastic single-ply membrane, such as EPDM, TPO, or PVC roofing membrane systems.

In order to assure that the expansion joint system and the roofing system will work properly together, one of the most critical questions specifiers must ask is whether the counterflashing on the expansion joint system is compatible with the roofing membrane and the adhesives being used. Proper tie-in of the roofing membranes with the expansion joint systems is essential to good roof waterproofing. When roofing materials and adhesives fail to bond with the expansion joint membrane, the reaction can be a failure point that leads to subsequent degradation of the roofing and potentially other parts of the building. It is important therefore for the joint membranes to be chemically compatible with the roofing materials. Good information from the manufacturer should clearly lay out the recommendations regarding roofing membranes and adhesives that are compatible with the expansion joint counterflashing.