Tag Archives: Division 07

XPS delivers high R-values in below-grade applications

A new study from the Alaska University Transportation Center, University of Alaska Fairbanks, recently reported on R-values measured on insulation removed from below-grade applications in harsh climates. This supplements data from two previous similar research projects. All the three studies reported the in-service R-values per inch of extruded polystyrene (XPS) and expanded polystyrene (EPS) insulation installed under roads and airport runways with the time in-service ranging from one to 31 years.

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Specifying metal rainscreen assemblies

Metal can be formed into several shapes, sizes, colors, and textures to meet almost any aesthetic. If specified correctly, the assembly will last for the life of the building with very few issues. Three broad categories—composites, insulated metal panels (IMPs), and single-skin—of metal rainscreens are widely used.

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Rainscreen walls: An updated definition for today’s construction environment

The term rainscreen refers to a building system fulfilling one of the main functions of an exterior wall—to screen out rain and keep a wall dry. While at one time that system would have encompassed moisture control alone, the complexity of exterior wall assemblies now requires a more integrated approach. Multicladding aesthetics with the benefit of continuous control layers are achievable with new rainscreen system designs.

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New IBC rules for insulation in unvented enclosed roof framing assemblies

Unvented roof systems, where the insulation and air barrier are applied directly to the underside of the roof deck, are common in applications where designers are seeking cost-effective and energy-efficient roof assemblies. However, designers of compact roof assemblies must consider vapor permeance and arrangement of the roofing materials to produce acceptable hygrothermal performance and low risk of condensation in the conditioned attic space. To this end, the 2015 version of the International Building Code (IBC) includes new provisions relating to unvented attic and unvented enclosed rafter assemblies that dictate how designers specify vapor retarders and placement of insulation in compact roof assemblies for condensation control.

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