Material and Methods exam 3

Preformed cellular tape sealants

( a solid sealant material) strip of polyurethane sponge material that has been impregnated with a mastic sealant. Arrive in a compressed state, and expand to fill the joint once applied.

Low-range sealants,

*(caulks)* are materials with very limited *elongation*(stretching and squeezing) capabilities, up to +/- 5% of the width of the joint.

two types of plaster

*gypsum plaster* or *portland cement-lime plaster* (stucco).

Gaskets

- strips of various fully cured elastomeric (rubberlike) materials ( a solid sealant material)

Anodizing (surface finishes for aluminum)

A manufacturing process that produces an integral oxide coating on aluminum that is thousands of times thicker and more durable than the natural oxide film that would otherwise form. Acid bath process that takes oxygen from acid and combines it with the aluminum. Advantages of anodized finishes are their extreme hardness and, in most colors, their extreme resistance to weather and fading. Give an integral appearance with the aluminum surface.▫

Gypsum Plaster

A type of plaster. Abundant mineral. It is quarried, crushed, dried, ground to a fine powder and heated to 350°F in *calcining* process to drive off ¾ of water of hydration. One major disadvantage: *it is soluble in water* Advantages: *inexpensive, highly resistant to fire,*

Portland Cement Plasters

A type of plaster. Also known as Stucco. Portland cement-lime plaster is also known as stucco (Lecture 25). Similar to masonry mortar. Used where plaster is likely to be subjected to moisture, as on exterior wall surfaces, commercial kitchens, shower rooms, etc. Shrinks slightly during curing; requires frequent control joints to regulate cracking.

Rainscreen Cladding and Pressure-Equalized Wall Design for exterior walls

Allows wind pressure differences between inside and outside of exterior wall to neutralize themselves is known as *pressure-equalized wall design*. Create an airtight plane, called the *air barrier*, behind the outer face of the wall. Air barrier is protected from direct exposure to the outdoors by an unsealed, labyrinth-jointed layer known as the *rainscreen*. Between the rainscreen and air barrier is a space known as the *pressure equalization chamber (PEC)*. Pressure-equalized chambers must be divided into airtight compartments small enough that the volumes of air cannot rush through the joints in higher-pressure areas of the face and flow across the air chamber to lower-pressure areas, carrying water with them.

Entrances

Aluminum and Glass Framing Systems Systems of aluminum framed doors, hardware, aluminum framing, and glass typically used for commercial buildings.

Curtain wall systems

Aluminum and Glass Framing Systems Most high-performance, sophisticated, and costly of the aluminum and glass framing systems. Can be readily applied to any number of stories. Use stronger, stiffer aluminum sections that can resist higher wind pressures. Have more sophisticated internal construction and systems of sealing and water drainage that enable them to resist water leakage even under more severe conditions of wind-driven rain experienced in tall buildings.

Storefronts

Aluminum and Glass Framing Systems Similar in appearance to curtain wall, but are based on simpler, lighter framing elements that are less expensive and quicker to assemble. Most storefront systems span vertically no more than 10 to 12 feet. Typically installed between floor slabs or within wall openings, and do not hang from the building like curtain wall systems. More limited in their ability to resist wind loads and water penetration. Typically not used more than three to four stories high on a building. Used for floor-to-ceiling glass at ground level and also as a substitute for commercial aluminum window applications.

Expansion Joints in Metal and Glass Walls

Aluminum has a relatively high coefficient of thermal expansion. Because cladding is exposed to air temperature fluctuations as well as direct heating by the sun, it must be provided with expansion joints to allow thermal movement to occur without damaging the cladding or the building frame. Rubber blocks placed between edge of glass and mullions on either side prevent the glass from "walking" too far in either direction.

Sustainability in Aluminum Cladding

Aluminum is refined from bauxite ore, which is relatively plentiful. Embodied energy of aluminum is roughly 100,000 BTU per pound, seven times that of steel, making it one of the most energy-intensive materials used in construction. Recycled aluminum is produced using only a fraction of the energy, approximately 5000 BTU per pound. Large volumes of water are required for smelting. Wastewater from manufacture contains cyanide, antimony, nickel, fluorides, and other pollutants.▫

Aluminum Extrusions

Aluminum is the metal of choice for metal cladding systems for three primary reasons: It protects itself against corrosion. It accepts and holds a variety of attractive surface finishes. It can be fabricated economically into elaborately detailed shapes by means of the process of extrusion. Extrusion process is like squeezing toothpaste from a tube. Very intricate aluminum sections can be extruded for a variety of purposes. ▫

Concrete masonry backup walls (3)

Are usually stiffer than the veneer that they support. Can maintain structural integrity despite prolonged periods of wetting. Generally preferable to steel studs except where cost, material thickness, and/or weight are principal drivers.

Types of Surface finishes for aluminum

Baked Enamel Coatings , Powder Coatings, Fluoropolymer Coatings , Anodizing, Unfinished Aluminum + Oxidation

Fluoropolymer Coatings ( Surface Finishes for Aluminum)

Based on highly inert synthetic resins. Are exceptionally colorfast and resistant to all forms of weathering, including ultraviolet deterioration. Available in a broad spectrum of colors, including bright metallic finishes. Most expensive of the organic coatings and longest lasting, best of which can last 20 years or more under normal service.

plaster of Paris

Calcined gypsum, ground to a fine white powder, is known as Major component of interior finish materials in most buildings

Surface Tension

Causes water to adhere to the underside of a cladding component. Allows water to be drawn into the building. Provision of a *drip* on any underside surface to which water might adhere will eliminate the problem.

Aluminum and Glass Framing Systems- modes of assembly

Column-Cover-and-Spandrel System, Panel System, Unit-and-Mullion System, Unit System, Stick Systems

Baked Enamel Coatings ( Surface Finishes for Aluminum)

Consist of spray-applied acrylic or polyester polymers, sometimes modified with silicone. Provide finishes with very high glosses in a wide selection of colors.▫

Principal Design Issues for the construction of an exterior wall

Convey design intent and meaning + shape spaces between buildings Define the character of the project - further spatial and formal qualities Negotiate and define social relationships

Sustainability Considerations in Exterior Wall Systems

Design of the exterior wall has a greater effect on lifetime energy consumption than almost any other factor. Glass should be used where it can supply daylighting and provide views, but also limited to prevent overheating, glare, or excessive heat loss through the envelope. Windows that can be opened and closed by the occupants can help reduce energy costs, in some cases. Note humidity issues + cooling/heating lag. Opaque areas of the exterior wall should be well insulated. The entire envelope should be detailed for air-tightness. Fresh air to be provided by building ventilation system, not by air leakage through ext. wall. South-facing glass can be used to provide solar heat to the building in winter, but must avoid glare, local overheating, + UV deterioration of interiors. Consider using south-facing surfaces for electrical energy generation. ▫

Considerations when selecting Interior Finish Systems

Durability and Maintenance Acoustic Criteria Relationship to Mechanical and Electrical Services Changeability Cost - first cost/installed cost v. life-cycle costs Toxic Emissions from Interior Materials. ▫

Sloped Glazing

Every sloped glazing system is designed by its manufacturer to include an internal drainage system. This system collects any water that results from leakage or condensation and drains it to the outdoors. Glass surfaces are sloped rather than flat Slope enables gravity to assist in keeping water from ponding on the roof. It causes condensate to run to the lower edge of each light of glass before dripping off. Moves water through the drainage channels to the weep holes. International Building Code places restrictions on glass sloped more than 15 degrees from vertical. These are intended to prevent falling glass from injuring occupants below. Only glazing materials permitted without limitations are laminated glass and plastic. Alternately, a metal screen may be installed below the glass to catch the shards if a light breaks.

Plaster over Expanded Metal Lath (and the 3 coats)

Expanded metal lath is made from thin sheets of steel slit and stretched to produce a mesh of diamond-shaped openings. Plaster is applied in *three coats*: First coat is *scratch coat*, applied roughly + scratched while still wet using a notched darby, broom, or special rake to create a rough surface. Second coat is the *brown coat*, used to build strength, thickness, and to prepare a more level surface . Third coat is the *finish coat*. It is a very thin application of finish-coat plaster, about 1/16" thick. This three-coat system over metal lath is the premium-quality plaster process. Extremely strong and resistant to fire. Disadvantage: cost, largely attributed to labor involved. ▫

Rainscreen Principle in Metal and Glass Cladding

External gaskets in curtain wall systems need only serve as ___ also know as *deterrent seals *discourage water from entering without necessarily barring its entry altogether. Internal gasket serves as an air barrier, and the hollow spaces between the edges of the glass and the mullions act as pressure equalization chambers. If water penetrates through the outer seals, it is conducted within spaces between the inner and outer seals down to weep holes in the outer face of the system. ▫

Monolithic Stone Cladding

Fastened directly to the frame of the building. Weight of each panel is transferred to two steel support plates by means of edge pockets that are cut into both sides of each panel at the stone mill. Nonstructural backup wall is required.▫

Fire Barriers and Fire Partitions

Fire barrier must extend vertically from the top of one floor slab to underside of the next floor. Used to define smaller fire areas.

Types of Interior Walls (5 types)

Fire wall, shaft wall, fire barriers and smoke partitions, and other nonbearing partitions

Plaster Applied to Masonry

For the best work, three coats totaling 5/8 inch should be applied.

Fire wall

Forms a required separation to restrict the spread of fire. Extends continuously from the foundation to or through the roof. Openings in rated fire walls are restricted in size and area.

Glass-Fiber-Reinforced Concrete Curtain Walls

GFRC. Relatively new cladding material. Has several advantages over conventional precast concrete panels: Its admixture of short glass fibers furnishes enough tensile strength so that no steel reinforcing is required. Panel thicknesses and weights are about one-quarter of those for conventional precast concrete panels. Reduced weights saves money on shipping, makes the panels easier to handle, allows use of lighter attachment hardware, and allows loadbearing frame to be lighter and less expensive. GFRC can be molded into three-dimensional forms with intricate detail and an extensive range of colors and textures. Panels often attached to welded frame made of light gauge steel studs. Edges of GFRC facing are flanged so backer rods and sealant may be inserted between panels. ▫

three types of solid sealant materials

Gaskets, preformed cellular tape selants, and performed solid tape sealants

Plaster

Generic term that refers to any of a number of cementlike substances applied to a surface in paste form that harden into a solid material.

Inside glazed

Glass is installed or replaced by workers standing inside the building. More convenient and economical for a tall building. Requires a somewhat more elaborate set of extrusions.

Outside glazed

Glass must be installed or replaced by workers standing on scafolding or staging outside the building. Relatively simple set of shapes that are less expensive for a building that is only one to three stories tall.

Forces that Move Water Through a Wall (5)

Gravity Momentum Surface Tension Capillary Action Air Currents and/or Pressure Differentials ▫

Dual-Layered Glass Cladding

In a double-skin façade, the wall system consists of two distinct glass cladding systems separated by an airspace that is wide enough to allow service personnel to pass between them. Most often, one of the two skins is double-glazed, while the other relies on single glass.

Roofing Underlayment (sloped roofs)

Installed soon after roof framing is completed and sheathed.

the curtain wall

Introduced with the first steel-framed skyscrapers, built in late 19th c. Is an exterior wall supported at each story by the frame. Name derives from the idea that the wall is thin and "hangs" like a curtain on the structural frame, although most systems are supported from the bottom at each floor level. Earliest curtain walls were of masonry. Principal advantage of the curtain wall is that since it bears no vertical load (other than its own), it can be thin and lightweight regardless of the height of the building. May be constructed of any noncombustible material suitable for exposure to the weather, and can be constructed in place or prefabricated. ▫

Gravity

Is a factor in pulling water through a wall only if the wall includes an inclined plane that slopes into—rather than out of—the building. Usually simple to detail the exterior to avoid these types of inclined planes. Sometimes a loose gasket or errant bead of sealant can create this condition even if components are designed correctly. ▫

Primary Functional/Performative Requirements of Enclosure:

Keep Water Out** Prevent Air Leakage Control Light Control the Radiation of Heat Control the Conduction of Heat Control Sound

Four basic responses to preventing a leak:

Keep water away from the wall, if possible via overhangs or projections. Try to seal every opening. This "*barrier wall"* typically proves unreliable. Provide strategies for internal drainage or secondary defense, via cavities within the wall assembly that allow for drainage. Eliminate or neutralize the forces that move water through a wall. ▫

Gypsum board (plaster)

Least expensive of all interior finishing materials for walls and ceilings. Retains fire-resistive characteristics of gypsum plaster, but is installed with less labor by less skilled workers than lathers and plasterers. Also Many types available, including: regular gypsum board, *Type X gypsum* board (required for fire-rated assemblies) Many thicknesses, including ¼" (for tight radii), ½" (most commonly used), or 5/8" (for fire-rated partitions, greater stiffness, durability, sound deadening).▫

building felt

Made of matted cellulose fibers saturated with asphalt. Traditionally designated as either 15-lb or 30-lb, referring to the weight of material used to cover *"one square"* (100 square feet) of roof area. Today, often specified as "No. 15" or "No. 30", weighing slightly less than names suggest. Most common material made of one or two layers for roof underlayment

Powder Coatings ( Surface Finishes for Aluminum) & advantages

Manufactured with thermosetting powders that are composed of plastic resins, such as polyester, and pigments. Powder is electrically charged and then sprayed onto the aluminum which is grounded so that the powder adheres to it electrostatically. Advantages: Lower cost compared to fluoropolymers, durability, wide range of colors and finishes, and lack of organic solvents that cause air pollution. Manufacturing does not generate any volatile organic compounds (VOCs).

Prefabricated Reinforced Brick Panel Curtain Walls

Masons construct panels while working at ground level in a factory. Horizontal reinforcing may be laid into mortar joints or grouted into channel-shaped bricks. Vertical reinforcing bars are placed in grouted cavities of hollow-core bricks. Panels are self-rigid; they need no structural backup

Momentum

Momentum of falling raindrops can drive water through a wall only if there is a suitably oriented slot or hole that goes completely through the wall. Neutralized by applying a cover to each joint in the wall or by designing each joint as a simple *labyrinth.*

vertical expansion joints (Masonry Veneer Curtain Walls)

Must also be divided vertically by movement joints to allow the frame and the masonry cladding to expand and contract independently of one another.

lath

Plaster that may be applied directly to a masonry surface or to any of a group of plaster bases known collectively as.. Lath was historically thin wood strips, but today is typically either expanded metal or preformed gypsum boards.

Precast Concrete Curtain Walls & precast concrete sandwich panels

Precast concrete cladding panels - can be conventionally reinforced or prestressed. Factory production allows for high-quality molds and variety of surface finishes. precast concrete sandwich panels-thermal insulation is incorporated as an inner layer of the panel Reinforcing or prestressing of panels must be designed to resist wind, gravity, and seismic forces, and to control cracking of the concrete. Attachments must allow for relative movements of frame and cladding.

Double-skin facades can improve the performance of the building envelope in a variety of ways: disadvantages

Reduce unwanted solar heat gain. Increase daylighting potential. Minimize thermal conduction and radiation through the wall system. Provide a space for shading elements that is protected from the weather. Permit natural ventilation designs in tall buildings. Create a quieter building interior than is possible with conventional glazing systems. Disadvantages: May subtract as much as 5 to 10 % of the usable floor area of the bldg. Significant increase in construction cost over traditional curtain wall. They have become less common recently due to budget considerations.

Secondary Functional/Performative Requirements of Enclosure:

Resist Wind Forces Control Water Vapor Accommodate Movement Thermal Expansion/Contraction Moisture Expansion/Contraction Structural Movements Resist Fire - sometimes a primary function, depending on context Address Installation Requirements for the Exterior Wall Allow for Maintenance Weather Gracefully

Truss-Supported Stone Cladding

Sheets of stone are combined into large prefabricated panels by mounting them on structural steel trusses. Trusses designed to carry wind loads and dead load of stone to steel connection brackets that transfer these loads to the frame of the building. Sealant joints and nonstructural backup wall finish the installation. ▫

MEPS for large buildings

Specific floor areas are reserved for mechanical and electrical functions in larger buildings. In a large building, space is usually set aside in basement or subbasement level for pumps, boilers, chillers, electrical transformers, and other heavy equipment. At the roof are penthouses for elevator machinery, cooling towers, and ventilating fans. In very tall buildings, one or two entire floors may be set aside for mechanical equipment and the building is zoned vertically into groups of floors that can be reached by ducts and pipes that run up and down from each of the mechanical floors.

Basic Concepts of Exterior Wall Systems

The Loadbearing Wall The Curtain Wall

soft joint (Masonry Veneer Curtain Walls )and its benefits

There must be a __* (horizontal expansion joint)* beneath each shelf angle Prevents normal movements in the frame of the building from stressing the masonry veneer. Allows the veneer to expand and contract without distress. Cannot exceed the maximum safe compressibility of the sealant.

In order for water to penetrate a wall, three conditions must be satisfied simultaneously:

There must be water present at the outer face of the wall. There must be an opening through which the water can move. There must be a force to move the water through the opening. If any one of these conditions is not satisfied, the wall will not leak.

Posttensioned Limestone Spandrel Panels

Thick blocks of limestone joined with adhesives into long spandrel panels and posttensioned with high-strength steel tendons. Assembly is self-supporting between columns. Relatively costly type of panel because of their use of comparatively large quantities of stone per unit area of cladding.

Capillary Action

This is the surface tension effect that pulls water through any opening that can be bridged by a water drop. Primary force that draws transports water through the pores of a masonry wall. Can be eliminated by making each of the openings larger than a drop of water can bridge. Can also/alternatively provide a concealed *capillary break* somewhere inside the opening.

Unfinished Aluminum + Oxidation

Though it is a very active metal chemically, aluminum does not corrode away in service because it protects itself with a thin, tenatious oxide film that seals the surface of the metal and discourages further oxidation. Film protects aluminum but has a chalky, spotty appearance. As a result, aluminum is usually treated in some way to provide better control of its appearance.

Smoke Barriers and Smoke Partitions

Used in buildings where occupants are unable to leave the building in case of a fire. Smoke barriers are rated; partitions are unrated.

Aluminum and Glass Framing Systems

Used to construct windows, entrances, storefronts, and curtain walls.

Shaft Wall

Used to enclose a multistory opening through a building, such as a space for an elevator or spaces used for ductwork, conduits, or pipes.

types of plaster systems (3)

Veneer Plaster, Plaster Applied to Masonry, Plaster over Expanded Metal Lath

Veneer Plaster

Veneer plaster is least expensive of the gypsum plaster systems and is competitive in price with gypsum board finishes in many regions. Veneer plaster is least expensive of the gypsum plaster systems and is competitive in price with gypsum board finishes in many regions. Usually not more than 1/6 to 1/8 inch in total thickness.

Grid-System-Supported Stone Cladding (and its cons)

Vertical members of subframe erected first, designed to transmit gravity and wind loads from the stone slabs to the frame of the building. Horizontal members are aluminum shapes that engage slots in the upper and lower edges of each panel to attach them firmly to the building. Nonstructural backup wall is constructed as an air barrier, for thermal insulation, to house electrical wiring, and to support the interior wall finish layer (often plaster or gypsum board). Weakness of system: dependence on the integrity of the sealant joints. If joints leak, water may accumulate in the slots in the tops of stone panels.▫

Installation of Mechanical, Electrical and Plumbing (MEP) + Data Services

Vertical runs of pipes, ducts, wires, and elevators in a multi-story building are made through vertical shafts whose sizes and locations were determined at the time the building was designed - often by MEP consultant engineers. Before the building is finished, each shaft is enclosed with fire-resistive walls to prevent the vertical spread of fire. Horizontal runs of pipes, ducts, and wires are usually located just below each floor slab, to keep them up out of the way. May be left exposed or hidden above suspended ceiling. Sometimes services are run horizontally between the structural floor deck and a raised access flooring system. To house pipes where several *plumbing fixtures* are lined along a wall, a plumbing space (or chase) is created by constructing a double wall with space between.

Gunnable Sealant Materials

Viscous, sticky liquids that are injected into the joints of a building with a sealant gun. They cure within the joint to become rubberlike materials that adhere to the surrounding surfaces and seal the joint against the passage of air and water.

3 steps of firestopping of floor penetration

Within a plumbing wall, a layer of safing insulation is cut to fir and inserted by nand into a large slab opening around a cast iron water pipe.. Then a mastic firestopping compound is applied over the safing to make the opening airtight. Lastly, applying firestopping compounf around an electrical conduit at the base of a partition

Stick Systems (Aluminum and Glass Framing Systems)

a mode of assembly Principal components are metal mullions and rectangular panels of glass and spandrel material that are assembled in place on the building. Advantages of low shipping bulk and high degree of adjustability to unforeseen site conditions. Disadvantage: must be assembled on-site under highly variable conditions, rather than in a factory with controlled conditions and lower wage rates. Aluminum entrances and storefronts are also typically installed as stick systems.

Column-Cover-and-Spandrel System Aluminum and Glass Framing Systems

a mode of assembly Emphasizes the structural module of the building rather than creating its own grid on the façade. Custom design for each project must be created because there is no standard column or floor spacing for all buildings. Special care required in detailing spandrel panel support to ensure that the panels do not deflect when loads are applied to the spandrel beams of the building frame. ▫

Panel System Aluminum and Glass Framing Systems

a mode of assembly Made up of homogeneous units that are formed from sheet metal. Advantages and disadvantages are similar to the unit system. Production involves higher tooling costs of a custom-made die or mold, which makes it advantageous only for a building that requires a large number of identical panels. ▫

Unit-and-Mullion System Aluminum and Glass Framing Systems

a mode of assembly Offers a middle ground between stick systems and unit systems. Seldom used today. ▫

Unit System Aluminum and Glass Framing Systems

a mode of assembly Takes full advantage of factory assembly and minimizes on-site labor. Units require more space during shipping and more protection from damage than stick system components. ▫

backer rod

a spongy material that does not stick to the sealant is inserted to the joint to maintain the desired depth. The depth is between 1/8 and 3/8 inches

3 types of gunnable sealant materials

according to the amount of change in joint size that each can withstand safely after curing. Low-range sealants, Medium-range sealants , High-range sealants

metal stud backup walls (pros over masonry and cons)

advantages over masonry: Lighter weight Greater ability to contain thermal insulation and wiring Greater receptivity to a variety of interior finish materials Disadvantages more flexible and may deflect enough to cause cracking. Cracking may lead to water leakage, which may lead to corrosion of metal components, and deterioration of gypsum sheathing panels. ▫

Thermal Breaks. Required for what type of framing?

are internal components of insulating materials that isolate the aluminum on the interior side of the component from the aluminum on the exterior side. These are required in aluminum framing members.

Veneer wythe is erected..

brick by brick or stone by stone with conventional mortar, starting from a steel *shelf angle* that is attached to the structural frame at each floor.

High-range sealants

can safely sustain elongations of up to +/- 50 to 100% of the width of the joint. This category includes polysulfides, polyurethanes, and *silicones*. They do not shrink during curing. ▫

Smoke-developed rating

classifies a material according to the amount of smoke it gives off when it burns.

Fire dampers

close automatically if hot gasses from a fire enter the duct and are required in *ductwork* passing through rated assemblies. ▫

snap-on and snap-together features

commonly used in exruded aluminum curtain wall components

Fire-Rated Assemblies

divide the building into separate fire-compartments. Fire-Rated Assemblies are in hours (1,2,3,4, etc.).

rainscreen cladding

has come to be applied more broadly to any cladding system with a system of internal drainage, regardless of the extent of compartmentalization of the drainage space and the degree of pressure equalization that can be achieved. . More recent.

Medium-range sealants

have safe elongations of +/- 5% to 10% of the width of the joint.

Flame-spread rating

indicates rapidness with which fire can spread across a surface of a given material.

Flame Spread Index (FSI) and the classes

is a non-dimensional number which is placed on a relative scale. Class A: 0 - 25 Class B: 26 - 75 Class C: 76 - 200

masonry veneer

is a single wythe of brick masonry separated by a cavity from a structural backup wall.

temperatures that are best for sealing

not too hot, not too cold

Fire Resistance

of an assembly refers to its ability to resist the passage of fire from one side of the assembly to the other (an assembly property). Building code regulates the fire resistance of assemblies

rainscreen principal

originated with the concept of pressure-equalized wall design, and at one time it was used exclusively in reference to pressure-equalized cladding systems.

Combustibility

refers to the surface burning characteristics (a material property).

Sealant Joints in the Exterior Wall

seams that are closed with rubberlike compounds. Sealant joint widths are usually 3/8 to ¾ inch, but can be as small as ¼ inch and sometimes range up to 1 inch or more.

Servant and serve spaces

servant spaces are infranstructural spaces that hold mechanical installations, and serve spaces are occupiable

Allowable flame-spread and smoke-developed ratings are defined by ..

the building code.

sealant in three sided joints

the sealant is likely to tear unless a nonadhering plastic bond breaker strip is placed in the oing before the sealant

Preformed solid tape sealants

used in lap joints; are very sticky. ( a solid sealant material)