Douglas C. Gehring , P.E., CSI, Director, Marketing Technical Services at CertainTeed Gypsum, Inc. reports that glass-mat gypsum exterior sheathing is mold resistant and moisture resistant and "can be recycled back into new gypsum board products after demolition work. Glass fiber is added to all fire-rated gypsum board products so the extra glass is not an issue."

Coatings applied directly to concrete can waterproof interior surfaces without excavation and solve a unique problem for this Beijing Olympic Stadium. Photo courtesy of Xypex Chemical Corp

Chemists have also invented a coating that solves water infiltration problems in both new and existing buildings and which does not use petroleum products. Originally used in wastewater treatment facilities, this material is now used in many foundations. According to Les Faure, Advertising & Promotions Director of Xypex Chemical Corporation, "An applied coating of crystalline waterproofing solved the problems of water ingress due to a high water table at the Beijing Olympic Stadium's podium pit."

Some materials have been used since before the Egyptians built the pyramids. Rich Thomas, marketing manager of US Tile Company, reminds professionals that "Clay is just dirt!€¦Clay tiles contain 100 percent recyclable materials with no additives, making it a very green product." Clay tiles meet LEED^® credits not just for recycled content, but also can provide credit points for use of a material from an indigenous and regional resource.

"There is an average of eleven different materials in a typical residential wall and the relationship of each material to the other is important when looking at wall assemblies. In particular, the location of the vapor barrier is important so that the designer does not create a €˜composting building,' " stated Steve Klamke, Executive Director of the EIFS Industry Members Association (EIMA). "We are just scratching the surface on how walls and surfaces behave."

Building scientists test wall systems to understand how they perform as an integrated system. Most architects will specify test walls to make sure that the combinations of cladding, flashing, sheathing and moisture proofing work together to prevent moisture penetration. From a buildings' shoes to its hat, as the clothing of a building must work like a good high tech, weatherproof jacket, an analogy used by Les Faure, to keep moisture out, warmth in and to meet a designer's aesthetic goals.

DESIGNING WARM AND COOL ROOFS

Warm Roofs and Polyisocyanurate
Insulation is a material used to resist heat loss or heat gain in abuilding. Insulation is measured in R-values, the higher the R-value the better the material as an insulator. Polyisocyanurate (polyiso) roof insulation has some of the highest R-values in the industry, ranging from R-6 per inch to R-6 ½ per inch. This means that far fewer insulation panels are required in the roofing system to meet even the most stringent energy code values. When placing all roof insulation, overlapping insulation materials is good practice to prevent thermal bridging or heat loss, from structural components.

According to Lorraine Ross, "the Industry accepted standards for evaluating a polyisocyanurate roofing system include:

• ASTM C 177: Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus
• ASTM C 518: Standard Test Method for Steady-State ThermalTransmission Properties by Means of the Heat Flow Meter Apparatus
• ASTM C 1289: Standard Specification for Faced Rigid Cellular Polyisocyanurate Thermal Insulation Board
• ASTM C 1363: Standard Test Method for Thermal Performance of Building Materials

Polyiso applied to the roof of offices, health facilities, warehouses, retail and industrial manufacturing facilities and educational institutions should be overlapped to prevent thermal bridging. Photo courtesy of Atlas Roofing Corporation