Seeing the Urban Forests for the Trees: Secondary benefits of our cities’ wood

Photo courtesy M Magazine

In the wake of the devastation caused by the emerald ash borer, urban lumber harvesting has emerged as a response in the United States and Canada. Instead of grinding the wood into mulch, the urban wood movement promotes using urban forests to provide distinctive finishes for built spaces while also connecting those spaces to a piece of history. Designers, contractors, specifiers, and related professionals wishing to use urban wood must be aware of special considerations if they wish to take advantage of this unique resource.

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Bridging the Specification Gap between Divisions 03 and 09: Concrete and floorcovering associations unite

Photo © Michael Marxer (marxerphotography.com). Photo courtesy Mapei

Division 03 specifies concrete floor surface flatness requirements to be installed by the concrete contractor. However, Division 09 specifies the concrete floor surface flatness for the flooring installer that must be met before installing the floorcovering. Cooperation between the American Society of Concrete Contractors (ASCC) and six flooring associations has led to a solution for bridging the specification gap between Divisions 03 and 09.

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Mix Design Fundamentals: Considerations for concrete for slabs-on-ground

Photo © BigStockPhoto/Theerapol Pongkangsananan

Interior concrete should not crack or curl excessively requiring grinding before the flooring can be installed; exterior concrete should not crack or deteriorate prematurely from freeze-thaw cycles. Some argue concrete will always crack, and nothing can be done about it. This is most often an excuse when poor design or poor placement has resulted in excessive cracking or the real problem is too much mix design water, lack of welded wire reinforcement, or too little aggregate and poor curing methods.

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Improving Floor/Ceiling Sound Control in Multifamily Projects: Sound Testing Practices

The sound transmission class (STC) and impact insulation class (IIC) are ASTM-derived single number ratings that try to quantify how much sound a stopped by partition being tested. Laboratory testing involves an ideal setting for the floor/ceiling assembly—it is isolated from the walls, and there are no penetrations for HVAC, plumbing lines, sprinklers, can lights, or electrical boxes. In the field (i.e. F-STC and F-IIC), the floor/ceiling assembly often sits on load-bearing walls, is connected to the structure, and contains many ceiling and floor penetrations for the items just mentioned. Consequently, the code allows for a lower rating for field scores over those in the lab.

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Improving Floor/Ceiling Sound Control in Multifamily Projects

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Demand for better floor/ceiling acoustics in multifamily construction has been spurred by consumer desires, new guidelines from code bodies, and stricter enforcement of existing codes. This article reviews important new guidelines, delving into how construction manufacturers have created new products or enhanced existing ones in the pursuit of achieving higher acoustical performance.

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Designing for Comfort & IAQ: Air distribution per ASHRAE 55 and 62.1

Photo © BigStockPhoto/Pavel Losevsky

The goal of a room air distribution system is to provide thermal comfort and a healthy living environment for occupants in the space. This article looks at designing such assemblies for comfort and indoor air quality (IAQ) per ASHRAE 55 and 62.1. It examines the common method of overhead distribution, but focuses on partially mixed (i.e. most under floor air distribution [UFAD]) and fully stratified (i.e. displacement ventilation) systems.

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