facade cladding .research_team_erz_2013.22.10_arch.2430

FACADE CLADDING  Metal Panel, Rigid Insulation  Stone veneer Panels

TEAM: ERZ BUILDING TECHNOLOGY 4 MONIRUZ ZAMAN, ELVIS CHATTERPAUL, RACHIDA

AIR BARRIERS & SEALANTS •

Insulated metal panels qualify as Continuous Air Barriers. By keeping the internal and external environments separate, CABs enhance energy efficiency and are required by newer energy efficiency building codes and standards. The ability of the panels to seal to each other, as well as to the structure provides an excellent air barrier. This is why Insulated metal panels work so well at stopping the vapor drive between the interior and exterior of structures. By sealing the panels so well to each other and to the structure, moisture laden air is unable to pass from the warm side of the wall to the cooler side, greatly reducing the chance of condensation on the interior of the building or within the walls.

AIR BARRIERS & SEALANTS

• Stone cladding is a thin layer of real or simulated stone applied to a structure made of material other than stone. It is applied to concrete and steel buildings to comply with their original architectural design. • Stone veneer panels do not provide a sufficient air barrier to a structure. The air barrier is derived from the actual wall that the stone is being placed on. It is essentially for atheistic use only.

ATTACHMENT SYSTEMS • Insulated metal panels often require fewer structural supports than single skin panels because of their enhanced spanning and load bearing capabilities. This provides an efficient and economical building envelope.

ATTACHMENT SYSTEMS Insulated Metal Panel

BASE ANGLE

WALL PANEL CLIP NON-SKINNING BUTYL SEALANT

CONCRETE ANGLE TRIM

FASTENER

SILL TRIM

URETHANE SEALANT

ATTACHMENT SYSTEMS & FIRE SAFETY • Typically stone cladding is affixed to the wall of a structure using a mortar mix. Using natural stone can be heavier than simulated stone, which often needs mechanical fixing to be adhered to a structure. Anchors must be used to attach and support the stone panels to the building's primary or secondary framing system. Mechanical fixing could be using shelf angles or a stone clip. Lightweight structures would use plywood bracing as an alternative to fiber cement sheets.

ATTACHMENT SYSTEMS & FIRE SAFETY • Stone wall systems are not considered to provide any improvement in fire safety for the building exterior wall. In high-rise buildings stone wall systems can pose a serious safety hazard when a fire occurs that breeches the exterior envelope. When stone is exposed to intense heat from fire it can crack and the cracked portions of stone can fall from the building, putting lives in danger from falling stone.

THERMAL INSULATIONS & R’ VALUES •

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Insulated metal panels provide continuous insulation. This means that insulation runs continuously across all structural members without thermal bridges. This is accomplished by utilizing a concealed clip and a double tongue-and-groove interlock, effectively creating a thermal break between the exterior panel skin and the interior panel skin. Continuous insulation is important because thermal bridges and discontinuities introduced by compressing non-rigid insulations cause the in-place R-value of the assembly to be less than the tested Rvalue of the insulation used. With the insulating capabilities of insulated metal panels, less insulation space is needed to comply with building energy efficiency codes compared to fiberglass systems. Buildings using non-rigid insulation, such as fiberglass, can require up to four times the amount of insulation space compared to insulated metal panels. Insulated metal panels do not experience significant thermal drift due to the metal exterior and interior skins of the panels combined with the closed cell structure.

THERMAL INSULATIONS & R’ VALUES • Thin stone wall systems derive their thermal performance characteristics primarily from the amount of insulation placed in the wall cavity or within the backup wall. The stone and supporting elements of the wall provide little to no insulating value.

METAL PANEL CONNECTIONS • Metal panels are assembled as a unit at the shop and brought to the site to be attached to the building. By the use of various clipping systems the panels are attached to studs or the exterior wall system.

METAL PANEL ASSEMBLY • Metal panels are assembled with each other and are best placed when used by the specified joint type. They are attached to the exterior wall or studs with screws and clips.

METAL PANEL ASSEMBLY • Metal panels can be attached to steel structural elements and concrete structural elements such as beams.

STONE VENEER PANELS

• Stone veneer panels are attached to a building by using a clipping system on the stone element and the building’s element which will hold the panels. The panels are uniquely marked and each panel has to be placed at the correct location of the building.

STONE VENEER PANELS

• Stone veneer panels are assembled in various ways depending on the manufacturer, but usually it is assembled like the picture above. Several layers are attached to each other to form the finished form of a stone panel that will be clipped to a structure.

STONE VENEER PANELS

3-d figure of the general assembly of stone veneer panels with other elements of building.

CASE STUDY BUILDINGS Glazer children’s museum Architect: Gould Evans Location: 288 Aviation Avenue South Burlington, VT USA.

• The Glazer Children's Museum had only a 16-month construction and move-in timeframe and it required exterior cladding that could be installed quickly. The design team also wanted a striking building to serve a demonstration tool, that taught children about sustainability and protecting the environment.

CASE STUDY BUILDINGS

• The Glazer Children's Museum used the panel system in the facade because of how quickly it can be assembled and installed. The subtle grayish panels allow the more colorful parts of the building stand out and communicate with the children.

CASE STUDY BUILDINGS Chesapeake Energy building Oklahoma city, Oklahoma Completion: march 2012 Construction Type: Facade Renovation

• After a severe hailstorm, the exterior panel system was damaged a lot. Originally, it was planned to remove all damaged panels and replace them with new panels. After realizing that the panels and glass were very integrated with each other, therefore, only removing the panels was not possible. It would cost too much and take too much time to replace both the panels and the glass.

CASE STUDY BUILDINGS • So a “over-cladding” system was used. New panels would go on top of old panels and the old panels would serve as air and moisture barriers. If it were to be damaged again, they can take only the damaged panels from the newly installed ones which aren’t very much connected with the glass.

CASE STUDY BUILDINGS NYCCT VORHEES BUILDING Brooklyn, New York Construction Type: Renovation

• The Voorhees building was completely renovated for a better look and functionality. The ground level exterior around the building is a stone veneer cladding. It gives a clean smooth look and a sense of solid feeling compared to rest of building’s façade. which is a curtain wall system. This system was most likely used as part of the façade due to the fact that stone us very good against moisture, it is cost efficient, and easy to install.

CASE STUDY BUILDINGS • While under construction, the stone is covered with plastic while the jointing mixture is settling to control moisture from getting onto the mixture.

Rainscreen system • How it works? The purpose of a rainscreen system is to keep water out of a building :It works like a water barrier. This system is designed by keeping the cladding separated from the building through the uses of furring strips or a specialized rainscreen products. The efficacy of the system depend on the spacing between the cladding and the exterior wall as it can change the way the water penetrate through the structural wall assembly.

Rain Screen Wall. A “rain screen” approach resists rain penetration in three ways: 1) the exterior cladding layer sheds most water at its outer surface;

2) it anticipates that some water will penetrate behind the outer surface, and intercepts it with a dedicated air space/capillary break; and 3) this space is vented to the outside to not only assist drainage but to encourage drying as well. The air space or capillary break allows more free drainage than the “concealed barrier, "diverting water downward by gravity. The air space /capillary break is typically at least 3/8" in width, and can be kept open by spacer materials (furring, drainage mats, profiled boards, and the like) which have been shown to provide superior “drainage efficiency.”9 Finally, venting the air space to the outside not only assists drainage but encourages additional drying as well. This is important, since the “drying rate” can be more significant than “drainage” for long-term performance and durability of exterior building walls.

FORMS OF RAINSCREENS 1- Ventilated rain screen system Featured a continuous air space open at top and bottom to encourage airflow and convective drying when water gets between the cladding and the exterior wall of the building due to wind –driving rain, bulk water shedding , or capillary actions through porous cladding. The cavity must be protected with overhangs and screens so that bulk water and insects will not get in. A continuous moisture barrier should be used in addition to the rain screen system and a Water resistant rigid insulation

PRESSURE EQUALIZED RAINSCREEN SYSTEM The previous system assumes that water will inevitably get behind the cladding . In contrast, a pressure equalized rainscreen system are designed to prevent moisture from entering in the first place. Even though this system allows drainage it cannot be open at the top as this will prevent pressure equalization.

The pressure equalized system is compartmentalized into discrete chambers, taller than they are wide. These ventilation cavities respond to constantly changing wind pressure.

When the wind enter from the bottom and can’t find a way out, the air pressure inside the cavity pushes the wind back stopping water from entering

Natural stone panels and Metal panels Natural stone, metal panels, and architectural precast concrete wall cladding systems are similar in that they are large format panels that are attached at discrete points to their structural backup . The panels rarely leak -- 40 mm of granite, 1.2 mm of aluminum and 4" of concrete are all essentially perfect barriers. However, the large numbers of joints between panels do often leak, since sealant cannot be perfectly applied and will not last indefinitely. Hence, these systems should be designed as drained systems. It is relatively easy and inexpensive to apply a drainage plane and a cavity behind such systems.

METAL PANEL & STONE VENEER RAINSCREEN SYSTEMS The popularity of ventilated rainscreen systems have found there favor for Metal Panels as well as stone veneer. The key benefit is the elimination of the joint sealer, which requires maintenance, collects dirt and can stain or discolor the metal panels. Additionally the natural ventilation adds to the longevity and thermal performance of the façade.

GENERAL RAINSCREEN BENEFITS • Eliminates exposed sealants at critical transitions (less maintenance). • Dramatically reduces air infiltration through pressure equalization as well as more effective air barrier placement. • Eliminate mold/mildew from interior space. • Back ventilation allows for quick moisture evaporation, thereby extending the life of the cladding, insulation, sub-framing. • Air space behind the claddings, dissipates radiant heat through the chimney effect.