A double-skin facade is a cladding assembly that responds to energy efficiency demands and provides transparency. It makes sense where daylighting, protected shading, and transparency are desired.

It is comprised of two surfaces or walls separated by an air cavity that is ventilated by either mechanical/natural means. The skins can be fixed and/or operable, glass, louvers, etc. Shading devices are often integrated into the facade. The air cavity can be as narrow as a few inches but is typically 3 or more feet deep to allow access for maintenance.

The system takes advantage of temperature/pressure differences of air inside and outside the cavity (stack and cross ventilation), to increase air flow and decrease heating/cooling loads on the building.

Concerns include the loss of usable floor space and the cost of an additional skin and its supporting structure. A double wall system is complex and requires a whole building approach that considers several disciplines, including mechanical and structural engineering, thermal analysis, and lighting design.

RESOURCESSeeking innovative alternatives: Kieran Timberlake Associates pumps research into architecture, Sara Hart, Architectural Record. http://archrecord.construction.com/innovation/2_Features/0310KieranTimberlake.asp

More Thank Skin Deep: An integrated facade strategy helps designers create more comfortable and better-performing glass buildings, Joann Gonchar, Architectural Record: July 2010. http://continuingeducation.construction.com/article.php?L=5&C=685

Ventilated Double Facades: Classification and illustration of facade concepts, X. Loncour, A. Deneyer, M. Blasco, G. Flamant, P. Wouters, Belgian Building Research Institute: Oct. 2004. http://www.bbri.be/activefacades/new/download/Ventilated%20Doubles%20Facades%20-%20Classification%20&%20illustrations.dvf2%20-%20final.pdf

CONSTRUCTION SYSTEM

DOUBLE-SKIN FACADE ASSEMBLY

RESEARCH

PRECEDENT Cambridge Public Library, Cambridge, MA. A double-skin facade mitigates direct solar penetration with horizontal louvers and laminated glass visors.

HEATING Closed vents at top and bottom of cavity allow air to heat up, creating a thermal barrier between exterior and interior. This air can be distributed to the building to help fulfill heating needs. COOLING Vents are opened to allow cool air to enter at base and exit the top as it warms, via the stack effect, to help lessen cooling loads.

GLASS Tempered glass is approximately 4X stronger than annealed glass in bending. It can also withstand greater deflection than annealed glass of the same thickness, and is far more resistant to impact and thermal stresses. Tempered glass breaks into tiny, square-edged granules (safety glass). Annealed glass breaks into large, sharpened pieces.

GLASS, CONTINUED Building codes require that if there is a walking or other usable surface under a tempered glass opening, a protective screen must be provided below it to protect people in case it the glass spontaneously breaks. Another option is to use heat-soaked tempered glass (which is expensive) or laminated glass.

CONSTRUCTION SYSTEM

RESEARCH

SEISMIC ZONECONSIDERATIONS

An important physical trait of earthquake safe structures is flexibility. Rigid structures collapse from the movement caused by an earthquake. Taller structures are inherently more flexible than 2-3 story structures. Shorter structures require greater amounts of reinforcement to withstand earthquake forces.The construction materials used in structures can reduce the damage caused by an earthquake. Wood and steel have greater flexibility than stucco, unreinforced concrete, or masonry.Nonstructural elements like exterior cladding, parapet walls, canopies, stacks, partitions, doors, windows, suspended ceilings, egress, MEP and communications equipment, elevators, furniture, etc. must be braced to prevent partial or total damage.Options: construction type (corresponding seismic properties): Timber frame (good energy absorption, light weight, framing connections critical); reinforced masonry/concrete walls (good energy absorption w/ well integrated walls and floors; steel frame w/ masonry walls (good energy absorption w/ small bay sizes and uniform building plan); steel frame, eccentrically braced (excellent energy absorption, connections critical); pre-cast concrete frame (poor performer w/out special energy absorbing connections).

RESOURCESDesigning Earthquake Safe Buildings and Structures, StruCalc, Inc. 5/12/08. Accessed 3/24/13 http://www.strucalc.com/general-engineering/designing-earthquake-safe-buildings-and-structures/

Seismic Design Principles, Gabor Lorant, Lorant Group, Inc. & Gabor Lorant Architects, Inc. 03-15-2012. Accessed 3/24/13. http://www.wbdg.org/resources/seismic_design.php. Building Construction Systems Principles, Materials, and Systems. Mehta, Madan et. al., Prentice Hall, New York: 2010.

METHOD.Construction Waste Recycling

Kenyon Duncan

Haul Away Recycling - Deconstruction Specialists - Boulder, COComplete Dismantling

We can provide a turnkey deconstruction service, from obtaining all required permits to completion. Selective Dismantling & Removal

Remodel, addition, or pop-top, we have the expertise to accomplish your goals. Tenant Finish & Interior Removal

We do it all, from office buildings to bank interiors. Concrete Breaking & Removal

We are experienced in the recycling of driveways, slabs, sidewalks, retaining walls, and foundations. Lead Removal

Haul Away Recycling, Inc is fully licensed and certified to safely remove lead. Mechanized Demolition

We provide machine demolition as an alternative for structures not suited to manual deconstruction due to cost effectiveness, non-dismantleability, or lack of inherent resources worth salvaging.

Whole Building ReuseWe provide services to save and move a structure when this is a viable option.

Resources:http://www.haulawayrecycling.com/index.html

http://constructionwaste.sustainablesources.com/

CONSTRUCTION METHODOLOGYgreen roofREFERENCES

http://www.sustainablebuild.co.uk/RoofPlants.html

http://www.epa.gov/heatisland/mitigation/greenroofs.htm

http://www.greenroofs.org/

http://www.npr.org/templates/story/story.php?storyId=95005398

• A green roof, living roof, eco-roof, or rooftop garden is a vegetative layer grown on a rooftop, planted with specific vegetation to improve the energy efficiency of a building

• Intensive green roofs use plants from 1-15’ high and require deep levels of soil and a weight-loading roof; not suitable for domestic buildings

• Extensive green roofs use low-lying plants from 2-6” high, require a few inches of soil for support, and need a low weight-loading roof; they require little maintenance and can be used on sheds, garages, houses, balconies, extensions, outhouses, and commercial buildings

• Green roofs consist of a waterproof layer, root repellent membrane, filter cloth (allows water to drain but prevents soil escaping), moisture blanket (ensures water retention for plant life), drainage system, soil substrate, seeds, and plants

• Green roofs provide cooling in the summer and insulation in the winter, filter toxins from air and water, reduce CO2 emissions, retain rainwater (reduces the likelihood of flooding), reduce urban temperatures and smog, insulate against sound and noise, enhance biodiversity, use recycled materials, and improve quality of life

PRECEDENT: California Academy of Sciences, Golden Gate Park, San Francisco, CA; 1.7 million plants reside on the 2.5-acre green roof, and the plants and soil insulate the building and trap rainwater; designed by Renzo Piano

Layers of a green roof system

research

prefabricated constructionPrefabrication is the practice of assembling components of a structure in a factory or other manufacturing site, and transporting complete assemblies or sub-assemblies to the constrcution site

Advantages: The need for formwork, shuttering and scaffolding is greatly reduced Construction time is reduced and buildings are completed sooner On-site construction and congestion is minimized Quality control can be easier in a factory than on a construction site Less waste

Disadvantages: Transportation costs Placement of large assemblies can be difficult Local jobs may be lost

Zenkaya House

An all in one prefabricated house that can be shipped to any location.

Sustainable Construction Strategy Prefabrication & ModularityPrefabrication is the practice of assembling components of a structure in a factory or other manufacturing site, and transport-ing complete assemblies or sub-assemblies to the construction site where the structure is to be located. The term is used to distinguish this process from the more conventional construction practice of transporting the basic materials to the construc-tion site where all assembly is carried out.

The theory behind the method is that time and cost is saved if similar construction tasks can be grouped, and assembly line techniques can be employed in prefabrication at a location where skilled labour is available, while congestion at the assembly site, which wastes time, can be reduced. The method �nds application particularly where the structure is composed of repeat-ing units or forms, or where multiple copies of the same basic structure are being constructed. Prefabrication avoids the need to transport so many skilled workers to the construction site, and other restricting conditions such as a lack of power, lack of water,

http://en.wikipedia.org/wiki/Prefabrication

Advantages - Self-supporting ready-made components are used, so the need for formwork, shuttering and scaffolding is greatly reduced.- Construction time is reduced and buildings are completed sooner, allowing an earlier return of the capital invested.- On-site construction and congestion is minimized.- Quality control can be easier in a factory assembly line setting than a construction site setting.- Prefabrication can be located where skilled labour is more readily available and costs of labour, power, materials, space and overheads are lower.- Time spent in bad weather or hazardous environments at the construction site is minimized.- Less waste may occur- Advanced materials such as sandwich-structured composite can be easily used, improving thermal and sound insulation and airtightness

Disadvantages- Leaks can form at joints in prefabricated components.- Transportation costs may be higher for voluminous prefabricated sections than for the materials of which they are made, which can often be packed more efficiently.- Large prefabricated sections require heavy-duty cranes and precision measurement and handling to place in position.- Larger groups of buildings from the same type of prefabricated elements tend to look drab and monotonous.- Local jobs may be lost, if the work done to fabricate the components being located in a place far away from the place of construction. This means that there are less locals working on any construction project at any time, because fabrication is outsourced.

quick assembly

low costeasy to transport

A modular system should consist of scalable, reusable modules, as well as a rigorous and well-defined organizational interface. Modular construction allows for efficiency and speed while transporting materials and constructing the building. It also reduces the amount of waste produced, and becomes a flexible working process in which modules can be added or removed depending on necessity.

sources:http://en.wikipedia.org/wiki/Modular_designhttp://www.archdaily.com/255002/seven-modular-housing-in-co-vas-salgado-e-linares-architects/

ADDOMO (Seven Modular Housing in Cova)Salgado e Liñares ArchitectsBertamiráns, Ames, Spain

construction methodology: surface module efficiency patty gut | arista winery | russian river valley, ca

IDEACommonly manufactured material modules (4x8 etc) are cut at angles and folded to create the walls and surfaces. The angle of the cut sets up the adjacent wall through the folding action. The entire surface is cut from one continuous rectangle. This decreases construction waste and time.

+ FOLDINGPRECEDENTConcrete block modules in the GP House by Bitar Arquitectos are offset, doubled and folded to create a continuous surface which helps reduce con-struction waste.

http://continuingeducation.construction.com http://seek.autodesk.com http://www.ib-rauch.de http://en.wikipedia.org

MASS TIMBER CONSTRUCTIONhttp://www.masstimber.com

COMMON TYPES OF ENGINEERED WOOD PRODUCTS:

Cross-Laminated Timber (CLT) Glue-Laminated Timber (glulam) Laminated Strand Lumber (LSL) Laminated Veneer Lumber (LVL)

The University of British Columbia Earth Sciences Building is a five-story wood structure that uses CLT, glulam, and LSL. Architect: Perkins+Will Canada Architects Co.

modern mass timber refers to a family of products including sawn stress-grade lumber, timber tongue and groove decking, glulam, and CLT—that offer advantages in terms of increased strength, and also have quickened the construction process and enabled the use of wood products as solid walls, floors, elevator shafts, and columns to construct an entire building. Modern heavy timber products are particularly suited to mid-rise/multi-family housing, schools, large-span recreation centers, and supermarkets—buildings that must stand up to extreme loads caused by strong winds, heavy snow loads, and earthquakes. (Architectural Record, CEC)

“Panel sizes vary by manufacturer. CLT is currently available in North America with dimensions up to 19-1/2 inches thick, 18 feet wide and 98 feet long.” “CLT is one type of new mass timber assembly that is comparable in strength to steel and concrete, but weighs less. A CLT panel has at least three glued layers of boards placed in orthogonally alter-nating orientation to the neighboring layers.”

-Arch. Record CEC

During a fire, the exterior layers of wood will char creating a layer of insulation that prevents the interior from burning, thereby maintaining structural integrity. Cross-section taken from 3-ply CLT panel protected by two layers of ½-inch gypsum board and exposed to the standard fire exposure (CAN/ULC S101) for 1 hour and 15 minutes.

Of the engineered products used in mass timber construction, cross-laminated timber (CLT) is one of the more interest-ing. Developed in Switzerland in the 1990’s this product has been used in a number of mid-rise building in Europe and Canada such as the eight-story H8 in Bad Aibling, Germany which was completed in three weeks. (http://arstechni-ca.com) A recent continuing education course sponsored by the wood industry explains the definition of mass timber:

Architects for a project in England called Stradhaus “found that compared to concrete, a wood building offered cost savings of more than 15 percent, and that 186 tons of carbon were sequestered within its structure.” Codes in most U.S. states and Canada now allow the use of wood for five and six-story structures. Mass timber construction has the potential for even taller buildings of up to 30 stories according to Canadian architect Michael Green. CLT can also be used in combination with concrete as in the case with the Okanagan Campus Fitness and Wellness Centre in Kelowna, “Designers chose a wood-concrete composite floor system in part to provide a high level of vibration performance. With a sandwich of 3.5 inches of LSL, one inch of foam board insulation and four inches of reinforced concrete, the wood-concrete composite system's acoustic performance offers excellent sound absorption.” Another important aspect of mass timber construction is seismic performance. When it comes to earthquakes weight matters as explained here: “Since forces in an earthquake are proportional to the weight of a structure, wood-frame buildings that are properly designed and constructed perform exceptionally well.” This was proven in Japan on tests run on the world’s largest shake table. Three and seven story full scale CLT buildings were exposed to up to 7.2 magnitude accel-eration and “performed remarkably well . . . The CLT buildings showed ductile behavior and good energy dissipation. Such behavior was mainly influenced by the mechanical connections used.” (FP Innovations) Source - Architectural Record, “Mass Timber and Wood Framing”, http://continuingeducation.construction.com

Precast Concrete

What is precast?Precast concrete products are cast in molds in a factory setting. These products benefit from superior quality control achievable at a production plant. Cost savings are realized when shapes are duplicated. Precast products range from concrete bricks and paving stones to bridge girders, structural components, and panels for cladding.

Precast concrete is widely used for: Multi-family housing (low, mid-rise) Hotels and Motels Retirement Homes Security facilities Schools Office Buildings Warehouses Manufacturing Facilities Storage Facilities Big Box Stores Shopping malls Hospitals Libraries Airport Terminals Stadium and Arena Elements (seating, steps, pedestrian ramps, concession stands, locker rooms)Sound barriers (Highways, Industrial Sites) Security barriers (planters, walls)

Why?

Timeliness StrengthSafteyDurabilitySecure

Sustainability

During construction:

Watse minimizationRecycled contentLess community disturbance

During Life of Structure:

Energy performanceDisaster resistantCool (Temp)Indoor air qualityRecyclable

SIPS Panel ConstructionConstruction Technique

What is it?SIPS, also known as structural insulated panels, are building panels that can be used as walls, floors or roofs. They consist of two structural faces, like OSB and a core of rigid foam insulation. They replace traditional framing by combining all those components into a single panel that works in a modular form. They are fabricated off site and transported in pieces to the site where they are assembled. Exterior and interior materials can be applied to the faces and they act as structure for the building.

BenefitsThey can be constructed off site in a climate controlled environment. They break down into small panels, making them easy to transport on trucks. They contain the entire wall assembly within them so this helps limit time constructing walls on site. The modular nature of this system also cuts down time assembling the building because it can be assembled by panel, instead of individual pieces. They have high shear values. They are also very energy efficient and prevent thermal bridging, which allows heat to escape. They are also structural, allowing them to carry compressive loads without problem. They have a longer lifespan over traditional walls as well. They also cut down on waste during construction due to cutting pieces to fit.DrawbacksThey have a higher initial cost. They also require a mechanical ventilation system to move air because of how tight the buildings are. They also are not easily modified on site without special tools. Everything must be planned out ahead of time to make sure there are punctures in the correct areas, as these things are also hard to modify on site.

PrecedentThe Little Big Horn Health and Wellness Center used SIPS to construct a majority of the building, most importantly the gymnasium. The large panel sizes allowed them to support long spans and maintain high shear values. The panels created a very energy efficient envelope while providing primary and secondary support. The rapid constructability they provided also allowed the team to construct the building while designing it to meet a tight schedule.

Sourceshttp://www.nxtbook.com/nxtbooks/cbp/201206/#/32http://www.sips.org/about/home/faqs/#ahttp://www.fischersips.com/about/benefitshttp://www.builditgreen.co.uk/advantages-of-SIPs.html

Little Big Horn Health and Wellness Center