Glossary of Liquid Rubber Terms
Welcome to Liquid Rubber’s Glossary—your essential reference for understanding the terms, techniques, and materials used across construction, sealing, and surface protection.
Whether you're a contractor, facilities manager, DIY enthusiast, or specifying products for a build, this glossary offers clear, practical definitions focused on liquid rubber, waterproof membranes, and specialty coatings.
Use it to confidently navigate technical terms, make informed product choices, and better understand the performance features behind industry-grade waterproofing solutions.
In this glossary, you’ll learn about:
- Key components of liquid-applied systems
- Application methods and surface prep terminology
- Moisture control, structural sealing, and protective coating functions
- Material properties like adhesion, UV stability, and tensile strength
Acrylic Coating
Acrylic coating is a water-based protective layer composed of acrylic polymer emulsions containing pigment, binder, and carrier. It forms a flexible, durable, and UV-resistant membrane that shields surfaces such as roofs, concrete, and masonry from weathering, moisture, and chemical exposure.
Acrylic coatings are applied as thick liquid films that cure to seamless, elastomeric barriers widely used in waterproofing and protective applications.
Adhesion
Adhesion is joining two different materials or surfaces through intermolecular forces, including mechanical interlocking, physical interactions (such as van der Waals and hydrogen bonds), and chemical bonds (such as covalent or ionic bonds). Adhesion strength depends on surface properties like cleanliness, energy, and texture.
Aggregate
Aggregate is a granular material composed of sand, gravel, crushed stone, or recycled concrete, used as a fundamental component in construction. It is a filler and reinforcement in composite materials such as concrete and asphalt, providing structural stability, strength, and durability. Aggregates are classified by size, shape, and mineral composition.
Backroll
Backroll is a waterproofing technique where a liquid coating is first sprayed or brushed onto a surface, then immediately rolled with a paint roller to ensure consistent thickness, eliminate pinholes, and enhance adhesion.
This method improves membrane continuity and durability, especially on vertical surfaces, and is commonly used with high-quality waterproof sealant coatings for adequate protection.
Bitumen
Bitumen is a black or dark brown viscous material derived from the distillation of crude oil. It is composed mainly of high-molecular-weight hydrocarbons, including asphaltenes and maltenes.
It exhibits viscoelastic properties, waterproofing ability, and adhesive characteristics, making it widely used as a binder in asphalt pavements and waterproofing applications. Its hardness and softening point vary with composition and temperature.
Bleed-Through
Bleed-through refers to migrating underlying substances, such as bitumen or asphalt, through the applied waterproof membrane. This can cause discoloration or staining on the coating's surface, potentially affecting the membrane's appearance but not necessarily its waterproofing performance.
Capillary Action
Capillary action is the movement of a liquid within narrow spaces without external forces like gravity. The interplay of adhesive forces between the liquid and solid surfaces and cohesive forces within the liquid causes it. The height of liquid rise is inversely proportional to the tube diameter and depends on surface tension, density, and contact angle.
Caulking
Caulking applies a flexible caulk sealant to fill and seal gaps, joints, or seams in structures and piping. Its primary purpose is to create watertight and airtight barriers that prevent leakage of water, air, gas, dust, and pests.
Using a premium-grade sealant caulk ensures optimal adhesion and protection across various surfaces. It enhances structural durability, energy efficiency, and weather resistance.
Here are the main types of caulking based on their material, key properties, and typical applications:
| Type of Caulking | Key Properties | Typical Applications |
| Silicone | Highly flexible, waterproof, UV-resistant, durable, non-paintable | Bathrooms, kitchens, plumbing fixtures, exterior wet areas |
| Butyl Rubber | Excellent elasticity, waterproof, handles extreme temperatures, and is messy to apply | Roofing, gutters, flashing, exterior masonry |
| Elastomeric | High flexibility and durability, accommodates significant joint movement | Expansion joints, commercial buildings |
| Hybrid | Combining adhesion, flexibility, and durability properties | Varied substrates, general-purpose exterior and interior |
| Synthetic Rubber | Very flexible, paintable, suitable for exterior joints with frequent movement, weather-resistant | Exterior joints, frequently moving surfaces |
| Polysulfide | Excellent flexibility, UV and water resistant, long life (10-20 years), higher VOCs | Underwater applications, industrial sealing |
Color Sealant
A color sealant is a water-based, UV-stable, flexible coating that forms a durable, seamless waterproof membrane when applied in thick layers. It is used similarly to paint but requires heavy coats to build an effective waterproof barrier.
Typically applied on surfaces such as roofs, foundations, basements, and various building materials, including concrete, metal, wood, and brick, it provides protective sealing against water ingress and aesthetic color options.
Co-polymer
A copolymer is a polymer formed by polymerizing two or more monomer species. The process, called copolymerization, produces a polymer chain containing distinct structural units from each monomer. Copolymers can be linear or branched and are classified by the arrangement of monomers, such as alternating, block, or random sequences.
Cracking
Cracking is the formation of a complete or incomplete separation in a material, such as concrete, metal, or coatings, caused by stresses exceeding the material’s tensile strength. It results from mechanical loads, thermal expansion, shrinkage, fatigue, corrosion, or environmental conditions.
Cracks reduce structural integrity by creating physical discontinuities that decrease strength and increase permeability.
Cure Time
Cure time is required for a material, such as a polymer, adhesive, or resin, to undergo chemical reactions that transform it from a liquid or pliable state into a fully hardened, solid structure. This process involves cross-linking of polymer chains and is influenced by temperature and chemical composition factors. Complete curing ensures optimal mechanical and chemical properties.
Damp Proofing
Damp proofing is a construction method that applies moisture control to building walls and floors to prevent moisture entry into interior spaces. Defined by the American Society for Testing and Materials (ASTM), it involves materials resisting water passage without hydrostatic pressure. This differs from waterproofing, which resists water under pressure.
Methods include damp-proof courses, membranes, integral concrete treatments, and surface coatings.
Delamination
Delamination is the separation or splitting of layers in a laminated material or composite, typically caused by failure of the adhesive or bonding agent between layers.
It occurs in materials such as fiber-reinforced plastics, concrete, coatings, and metals, often due to mechanical stress, corrosion, thermal expansion, or moisture infiltration, leading to reduced structural integrity.
Drainage Board
A drainage board is typically made from high-density polyethylene or similar polymers. Its dimpled or ridged surface facilitates water flow away from foundations or walls. The board acts as a protective barrier that directs water by gravity to drainage systems, preventing moisture accumulation and reducing hydrostatic pressure on structures.
Elastomeric
Elastomeric describes materials composed of polymers with weak intermolecular forces and cross-linked molecular chains that exhibit viscoelasticity—combining viscosity and elasticity. These materials can undergo significant deformation under stress and return to their original shape when the stress is removed.
They typically have low Young’s modulus, high failure strain, and an amorphous structure above their glass transition temperature.
Epoxy
Epoxy is a thermosetting polymer characterized by epoxide groups, typically forming a three-membered oxirane ring. These resins cure through cross-linking reactions with hardeners, producing a rigid, chemically resistant, and adhesive material with high tensile strength and thermal stability. Epoxies are widely used in coatings, adhesives, and composite matrices.
Expansion Joint
An expansion joint is a gap or assembly in a structure designed to absorb movements caused by thermal expansion and contraction, seismic activity, or other forces. It allows connected parts to expand, contract, or shift without causing stress or damage to the structure. Expansion joints are used in buildings, bridges, pipelines, and pavements to maintain structural integrity.
Flashing
Flashing is a thin, impermeable material installed at joints, seams, and intersections in building envelopes to prevent water penetration.
Commonly made of metal, plastic, or rubberized membranes, it directs water away from vulnerable areas such as roof edges, chimneys, windows, and door frames. Proper installation is critical to avoid water damage and maintain structural integrity.
Foundation Coating
Foundation coating is a protective layer applied to the exterior or interior surfaces of a building’s foundation to prevent moisture, soil gases, and pests from penetrating the structure. These coatings are typically made from bitumen, rubber, acrylic, or cementitious compounds, enhancing concrete or masonry foundations' durability and water resistance.
The table below summarizes key types, their properties, and typical applications:
| Type | Key Characteristics | Application Notes |
| Asphalt-Based Coatings | Flexible, water-resistant bitumen emulsion; fiber-reinforced; damp-proof but limited hydrostatic resistance | Suitable for new construction and retaining walls under 4 ft; requires 50°F+ temperatures; 24-48 hr drying |
| Liquid Rubber Coatings | High elongation (up to 1200%), seamless, low-VOC, resists hydrostatic pressure (10-15 psi) and extreme temps | Creates a continuous barrier; easy soap-and-water cleanup |
| Acrylic Elastomerics | Breathable, UV-stable, COâ‚‚ barrier; good crack-bridging ability | Water-based; applied by brush, roller, or spray; soap-and-water cleanup |
Foundation Sealant Basement Coating
Freeze-Thaw Stability
Freeze-thaw stability is the ability of a material to withstand damage caused by repeated cycles of freezing and thawing. During these cycles, water within the material’s pores freezes and expands, generating internal pressure that can cause cracking, scaling, or structural weakening if the material’s tensile strength is exceeded.
Grade Line
Grade line is an imaginary or marked reference line representing a surface's intended elevation or slope, such as a road, railroad, or building foundation. It connects specified points of natural ground or design elevations, serving as a baseline for grading, excavation, and construction to ensure proper alignment and drainage.
Hydrostatic Pressure
Hydrostatic pressure is the pressure exerted by a fluid at rest due to the force of gravity. It acts equally in all directions at a given point within the fluid. It increases linearly with depth, proportional to the fluid’s density, gravitational acceleration, and the height of the fluid column above that point.
Hygroscopic
Hygroscopic refers to a substance's ability to absorb moisture from its surrounding environment, typically the air. Hygroscopic materials can attract and retain water molecules through physical adsorption or chemical absorption, often affecting their weight, volume, or physical properties. This characteristic is common in salts, polymers, and certain organic compounds.
Insulation Compatibility
Insulation compatibility refers to the ability of insulation materials to function effectively without chemical, physical, or mechanical degradation when in contact with other building components or coverings.
It ensures that insulation maintains its thermal performance, structural integrity, and durability by being resistant to moisture, temperature variations, and interactions with adjacent materials such as pipes, membranes, or coatings.
Joint Sealant
Joint sealant is a flexible material that fills and seals gaps between building components. It prevents water, air, and debris infiltration while accommodating movement caused by thermal expansion or structural shifts. Commonly used in construction joints, it ensures durability by maintaining adhesion and elasticity under varying environmental conditions.
Joint Movement
Joint Movement is the relative displacement or deformation between adjacent structural elements, typically managed with an expansion joint. Causes include thermal shifts, moisture variation, settlement, or seismic activity.
A high-performance waterproofing sealant helps protect joints by accommodating movement while sealing water, preventing cracks, and reducing long-term structural stress.
Liquid Applied Membrane
Liquid-Applied Membrane (LAM) is a monolithic, fully bonded, liquid-based coating applied directly to substrates such as asphalt, bitumen, or concrete. It is used in roofing, basements, terraces, and other waterproofing applications.
Upon curing, it forms a seamless and flexible rubber-like elastomeric waterproof membrane that provides protection against water ingress and accommodates thermal movement.
Membrane
A membrane in construction is a continuous, thin layer of waterproof material applied to surfaces to prevent water penetration. Typically 2 to 4 mm thick, membranes can be sheet-based or liquid-applied and are designed to be flexible, tear-resistant, and elastic to accommodate structural movement. They are used in areas requiring moisture protection.
Mil Thickness
Mil thickness is a unit of measurement equal to one-thousandth of an inch (0.001 inch or 0.0254 millimeters). It is commonly used to specify the thickness of coatings, films, and plastic sheets. Accurate measurement of mil thickness is essential for ensuring proper coverage, durability, and performance of protective and decorative coatings.
Moisture Barrier
A moisture barrier is a material used in construction to prevent water and vapor from penetrating building components. It protects structures from moisture-related damage, such as mold and deterioration.
Common types include polyethylene sheets, liquid-applied membranes, and weather-resistant foundation sealant options to enhance below-grade protection. Effective installation requires sealing all joints and edges to maintain continuous protection.
Mold Resistance
Mold resistance is the property of a material or coating that inhibits mold growth and proliferation on its surface. This is typically achieved by incorporating antimicrobial or antifungal agents into waterproofing or sealing compositions, which reduce moisture retention and eliminate organic substrates that support mold development.
Mold-resistant coatings maintain structural integrity by preventing microbial degradation in environments prone to moisture and humidity.
Non-Slip Finish
A non-slip finish is a surface treatment applied to floors or other substrates to increase traction and reduce the risk of slipping. It is typically achieved by incorporating abrasive aggregates or creating textured surfaces using epoxy or polyurethane. The degree of slip resistance depends on the texture's roughness, the type and amount of aggregate used, and the balance of safety and cleanability.
Overcoat Window
An overcoat window (or recoat window) is the specified time during which a subsequent coat of a protective or decorative coating can be applied over a previous coat without additional surface preparation. Applying a coat within this window ensures proper chemical bonding and adhesion between layers, maintaining coating performance.
Peel-and-Stick Membrane
A peel-and-stick membrane is a flexible sheet with a pressure-sensitive adhesive backing covered by a release liner. It is applied by peeling off the liner and adhering the membrane directly to a substrate. It provides waterproofing and crack isolation in construction applications such as roofing, basements, and tile installations.
Penetrating Sealer
A penetrating sealer is a low-viscosity material applied to porous surfaces, such as concrete or masonry, that absorbs into the substrate to form a chemical or hydrophobic barrier. It reduces water and contaminant intrusion while allowing moisture vapor to escape, enhancing durability without altering surface appearance or texture.
Ponding Water
Ponding water accumulates standing water on a flat or low-slope surface, such as a roof, pavement, or slab, where drainage or surface slope is inadequate to allow runoff. It typically persists for 48 hours or longer, accelerating material deterioration and structural damage if unresolved.
Primer
A primer is a preparatory coating applied to a substrate before painting. It improves adhesion of subsequent layers, enhances surface uniformity, and protects against corrosion, moisture, and other environmental factors. They are formulated for specific materials such as metal, wood decks, or concrete and typically contain pigments and binders to optimize coverage and durability.
Polyurethane
Polyurethane is a class of polymers composed of organic units linked by carbamate (urethane) bonds, formed by reacting polyols with di- or tri-isocyanates. It exists in various forms, ranging from flexible foams to rigid plastics, exhibiting properties such as elasticity, durability, and thermal stability. It is widely used in coatings, foams, adhesives, and elastomers.
Polyurea
Polyurea is a synthetic elastomer formed by the rapid reaction of an isocyanate component with an amine component, producing urea linkages in the polymer backbone. It exhibits high flexibility, chemical resistance, and fast curing times. Polyurea is moisture-insensitive, making it suitable for industrial applications for waterproof coatings, linings, and protective membranes.
Pot Life
Pot life is the period of time after mixing during which a multi-component material, such as coatings, adhesives, or resins, remains workable and can be applied or processed before its viscosity increases to an unusable level. It begins immediately after mixing and ends when the material starts to harden or cure, impairing its application properties.
Relative Humidity
Relative humidity (RH) in construction refers to the percentage of moisture in the air relative to the maximum amount the air can hold at a given temperature. It influences drying times of materials, moisture content in building components, and the potential for condensation, which can affect structural integrity and indoor air quality.
Reinforcement Fabric
Reinforcement fabric is a prefabricated mesh of high-yield steel bars or woven fibers, arranged in a grid pattern and embedded within concrete to improve its tensile strength and control cracking. Typically supplied in sheets with specified wire size and spacing, it is used in slabs, walls, and floors to distribute loads and enhance structural durability.
Roof Coating
A roof coating is a fluid-applied, monolithic, fully adhered membrane designed to protect and extend the service life of roof assemblies. Typically elastomeric, roof coatings form a durable, elastic film that provides waterproofing, resists UV radiation, and bridges small cracks and seams. They are thicker than paint and applied in multiple gallons per 100 square feet.
Rust Inhibitor
A rust inhibitor is a chemical compound that slows or prevents oxidation, causing rust on metal surfaces exposed to oxygen and moisture. It works by forming a protective film or barrier that reduces metal exposure to corrosive elements, thereby minimizing iron oxide formation and extending the metal's service life.
Seamless Membrane
A seamless membrane is a continuous, monolithic layer of waterproof material applied directly to a substrate. It forms a fully bonded barrier that prevents water penetration.
Typically 2–4 mm thick, it cures without joints or seams, allowing flexibility to accommodate structural movement while maintaining adhesion and long-term resistance to environmental conditions such as UV exposure and hydrostatic pressure.
Topcoat
Topcoat is the final layer of coating applied over primers or intermediate coats in a paint system. It provides a protective, often transparent or pigmented, resinous seal that enhances resistance to weather, chemicals, abrasion, and UV radiation.
A UV-stable polyurethane deck coating is an ideal topcoat for exterior surfaces exposed to sunlight and temperature fluctuations. Topcoats also contribute to the surface’s appearance by adding color, gloss, or texture and improving the coating system's durability.
Vapor Barrier
A vapor barrier is a material or membrane used in building construction to resist the diffusion of water vapor through walls, floors, ceilings, or roofs. Its primary function is to control moisture migration, preventing condensation and related damage such as mold growth and structural deterioration.
Vapor barriers are typically made from plastic sheets, foil, or coatings and must be properly installed and sealed to be effective.
Waterproof Sealant
A waterproof sealant is a UV-stabilized, water-based, flexible coating designed to create a durable, seamless waterproof membrane on various surfaces, including roofs, metal, wood, concrete, basements, foundations, gutters, and more.
Always consult Product & Application Support to ensure surface compatibility with primer or sealant, especially when discussing rubber membranes (EPDM).
