BT5: Cladding and Tilt-Up Construction

Cladding

The application of one material over another to provide a skin or layer that controls weather infiltration or serves an aesthetic purpose.

Aluminum, steel, stainless steel, copper, and composite materials.

Common Metals for Wall Cladding

Lap-seam Metal Panels

Metal sheets typically ship-lapped with adjacent panels, with gutters or sealant tape at panel edges.

Strips up to 4 ft wide and 20 ft long, with metal sheet thickness generally less than 0.05 in (1.10 mm).

Typical Lap-seam Panel Size

Composite Metal Wall Panels

Panels consisting of two metal sheets adhered to a core material; they are generally stronger than lap-seam panels and provide built-in insulation.

Foamed-insulation core, laminated-insulation core, and honeycomb core metal wall panels.

Types of Composite Metal Wall Panels

Foamed-Insulation Core Metal Wall Panels

Panels with metal facings and insulation foamed into place during fabrication.

Laminated-Insulation Core Metal Wall Panels

Panels with metal facings laminated to preformed insulation boards.

Honeycomb Core Metal Wall Panels

Panels with metal facings bonded to a honeycomb core.

Flat Plate Metal Wall Panels

Panels typically made from 1/8-in-thick metal plate and bent to the desired profile.

Very high impact resistance and durability compared with other metal panel types.

Main Advantage of Flat Plate Metal Wall Panels

Metal-faced Composite Panels

Panels consisting of metal facings adhered to a thin thermoplastic core and bent to the desired profile.

Flat plate panels have higher impact resistance, while metal-faced composite panels are generally thinner and less impact resistant.

Flat Plate vs Metal-faced Composite Panels

Generally less than 10 ft by 10 ft.

Typical Size of Flat Plate and Metal-faced Composite Panels

Aluminum

A corrosion-resistant cladding metal available in many finishes and colors.

clear anodizing

Aluminum should be protected with ____

Stainless Steel

A long-lasting cladding material available in finishes such as high reflectivity, smooth, brushed, and embossed.

304 Stainless Steel

Commonly used stainless steel alloy for standard corrosion resistance.

316 Stainless Steel

Stainless steel alloy containing molybdenum that provides greater corrosion protection, especially in coastal or highly polluted areas.

High initial cost, although its life-cycle cost can make it more economical than less durable steel.

Main Disadvantage of Stainless Steel

Steel Cladding

A lower-cost alternative that requires protection against corrosion, generally through a sacrificial zinc coating.

Galvanume / Zincalume

Steel with a hot-dip zinc and aluminum coating that provides better corrosion resistance than ordinary galvanized steel.

Coil-coated Metal

Sheet metal painted or coated before forming; the coating must be flexible and adhere well because the material is recoiled after painting.

Fluorocarbon Coatings

Exterior architectural coatings known for strong weatherability and resistance to fading and chalking.

Kynar 500

A fluorocarbon coating noted in the module for superior weatherability and resistance to fading and chalking.

Thermoset Acrylics

Durable coatings available in many colors and glosses, but pieces cannot be postformed because the acrylic finish is baked on.

Urethane Coatings

Coatings available in many colors and glosses with excellent chemical resistance.

Polyester Coatings

Durable coatings available in various colors and high glosses, widely used in high-quality architectural applications.

Weathering Steel

Steel used in plate form for cladding that develops a self-arresting oxidation texture.

Zinc

A highly corrosion-resistant metal that can be combined with titanium and copper to produce a strong, malleable metal with a natural blue-gray or pewter appearance.

Titanium

A costly cladding metal with a low coefficient of thermal expansion, high strength, and relatively low weight.

Titanium

Its coefficient of thermal expansion is about half that of stainless steel and one-third that of aluminum.

Insulation, air and moisture barrier, and metal stud framing.

Common Backup Wall Elements

batt insulation

Non-insulated metal panels typically rely on _____ placed within the stud wall behind the metal panel.

Building papers, house wraps, elastomeric coatings, and peel-and-stick waterproofing membranes.

Examples of Air and Moisture Barriers

Metal Stud Framing

Framing whose design must be coordinated with the metal panel design and fastening system.

Barrier System

A metal panel moisture-control system designed to prevent water penetration through the wall assembly.

Drainage System

A metal panel system designed to control and drain water that enters behind the exterior panel.

Rainscreen System

A metal panel wall system using a drainage cavity and secondary air and moisture barrier to manage water infiltration.

They can be dented by impact from swing-stage scaffolding and other maintenance equipment.

Why can Metal Panels be damaged on high-rise buildings?

Fluoropolymer, powder, and anodized coatings.

Durable Metal Panel Finishes

Shop-applied coatings generally perform much better than field-applied coatings.

Shop-applied vs Field-applied Coatings

Pitting

A condition in which weather and pollution attack the protective coating of metal panels, creating a pitted appearance.

Pitting

It is generally not a structural concern for aluminum and stainless steel but detracts from appearance.

Oil Canning

Pillowing or waviness of a metal panel caused by problems in fabrication, design, or installation.

Shadowing

A condition in which welds or stiffeners on the back of a metal panel become visible on the panel face.

Dissimilar Metals

Different metals used together that can cause water runoff staining and galvanic corrosion.

Galvanic Corrosion

Corrosion that occurs when different metals are in physical contact; the less noble metal corrodes.

Dissimilar metals should be physically separated or reviewed for galvanic action potential.

How can Galvanic Corrosion be prevented?

Water Runoff Staining

Staining or corrosion that can occur when water runs from one type of metal onto another material.

Water runoff from copper can stain and corrode aluminum.

Example of Dissimilar Metal Runoff

Approximately 7 to over 20 years

Typical Sealant Replacement Period

Approximately every 10 years

Recommended Cleaning Interval

Dirt and pollutants can attack the panel coating and cause pitting.

Why is Periodic Cleaning Important?

Concealed Interlocking Joint

A concealed joint between horizontal metal panels that allows panels to connect while hiding the fastening/interlocking mechanism.

180 mm to 650 mm.

Typical Panel Width

0 to 25 mm.

Available Panel Joint Width

Tilt-up Construction

A construction technique in which concrete wall panels or other elements are formed horizontally on a concrete slab, cured, then tilted vertically into position using a crane.

Tilt-slab

Another term for tilt-up construction.

Usually on the building floor slab or on a temporary concrete casting surface near the building footprint.

Where are Tilt-up Elements Formed?

Tilt-up panels are generally formed specifically for the building on site using molds that are usually not reused, while precast panels are manufactured at a separate facility.

Tilt-up vs Prefabrication

It is cost-effective and particularly suitable for low buildings.

Main Advantage of Tilt-up Construction

Prepare casting surface, construct forms, apply bondbreaker, install reinforcement, pour concrete, cure and remove forms, lift panels with a crane, and brace panels into position.

Basic Tilt-up Construction Process

Casting Surface / Pad

The concrete floor slab or temporary surface on which tilt-up panels are formed.

High-quality plywood, fiberboard, aluminum, or steel.

Common Materials for Tilt-up Forms

Reveals

Style accents or recessed shapes incorporated into the concrete panel through the formwork.

Embedded Components

Studs, gussets, and attachment plates placed inside the forms so they become embedded in the concrete.

Bondbreaker

A chemically reactive material sprayed on form surfaces to prevent the concrete from bonding to the form or casting slab.

To allow the cured concrete panel to separate from the casting surface during lifting.

Purpose of Bondbreaker

Why is Proper Bondbreaker Application Critical?

Improper selection or application can prevent panels from being lifted and may result in costly demolition and rework.

Rebar Grid

Reinforcing steel arranged inside the forms at the required spacing before concrete is poured.

Plastic Chairs / Dobe Blocks

Supports used to keep the reinforcing steel grid at the required distance from the casting surface.

Concrete Pouring

Concrete is placed into the forms to the required thickness around the reinforcement, steel inserts, and embedded features.

Stack Casting

A method of casting concrete slabs one on top of another when site space is limited.

Casting Pad

A separate concrete surface sometimes constructed for stack casting and removed after the panels are erected.

Crane in Tilt-up Construction

Equipment used to hoist the cured wall panels from horizontal to vertical.

Tilt Tables

Equipment formerly used to raise tilt-up panels before mobile cranes became common.

Bracing

Temporary supports used to hold tilted panels in position until the roof and other structural components are secured.

Foundation Connection

Tilt-up panels are set into the foundation and temporarily supported with braces until the building structure is completed.

Tilt-up Wall vs Traditional Wall Construction

Traditional walls are built through multiple steps using systems such as CMU, brick, steel studs, gypsum sheathing, or stucco; tilt-up walls are cast as large concrete panels and lifted into position.

Why is Tilt-up Construction faster than Traditional Wall Construction?

The exterior wall is largely finished when the concrete panel is tilted into place, reducing the number of construction steps.

Common Uses of Tilt-up Construction

Warehouses, call centers, distribution centers, retail stores, offices, storage buildings, schools, houses, hotels, and other industrial and commercial facilities.

Tilt-up Building Height

Tilt-up buildings can range from single-story structures to more than seven stories and can reach approximately 30 m in height.

Load-bearing Tilt-up Walls

Concrete walls engineered to work with roof and/or floor structures to resist building forces.

Tilt-up Wall Connections

Usually steel plates with headed studs embedded before concrete placement; connections are bolted or welded.

Shear Walls in Tilt-up Construction

Interior walls that may be added to provide additional structural stiffness.

Insulation in Tilt-up Panels

Insulation may be applied to either side of the panels or cast inside sandwich panels.

Thermal Mass of Concrete Tilt-up Walls

Concrete's high mass helps regulate interior temperature.

Soundproofing of Tilt-up Walls

The mass of concrete provides sound insulation.

Fire Resistance of Tilt-up Construction

Tilt-up buildings are fire-resistant because of the concrete construction.

Earthquake Concern with Older Tilt-up Buildings

Some older tilt-up buildings may be susceptible to collapse during earthquakes.

Inward Sagging of Tilt-up Panels

Panels can be designed to sag inward when damaged, helping minimize collapse.

History of Modern Tilt-up Construction

Modern reinforced-concrete tilt-up construction was first used in America around 1905 and became widely popular during the post-World War II construction boom.

Early Tilt-up Buildings

Most early tilt-up buildings were warehouses.

Schindler House

An early example of tilt-up construction, built in 1922 in West Hollywood, California.

Rudolf Schindler

Architect associated with the 1922 Schindler House, an early example of tilt-up construction.

Appearance of Tilt-up Construction

Modern tilt-up construction allows many finishes and shapes, including painted or stained surfaces, pigmented concrete, brick or stone features, sandblasting, acid-etching, curved walls, circular or elliptical openings, and extensive glazing.

Tilt-up Panel Construction

Walls are formed and poured as large concrete panels directly at the job site and then tilted into position.

Precast Concrete Construction

Concrete panels are produced at a manufacturing facility, cured, transported to the site, and installed.

Tilt-up vs Precast Concrete

Tilt-up panels are generally cast at the project site, while precast panels are cast at a separate manufacturing facility and transported to the project site.