How to Choose the Right Caulk or Sealant for Your Next Plumbing Project

With an abundance of different caulks and sealants on the market, it’s not uncommon to feel overwhelmed when choosing the right product for your next bathroom or kitchen project. Understanding what separates caulks from sealants is a great place to start.

You’ve probably noticed that “caulk” and “sealant” are often used interchangeably. That’s because both serve a similar purpose: acting as sealing agents to fill gaps and cracks and bonding agents between building materials, such as joining countertops to sink bases.

They are also both applied to surfaces to prevent leaks and used with or without a caulking gun, which is why sealant is technically categorized as a type of caulk.

Caulk vs. Sealant

The key distinction between caulk and sealant? Elasticity.

Caulk is typically made from a mixture of latex and acrylic materials, which make it more rigid and prone to shrinking when cured.

A sealant offers superior elasticity and water resistance because it primarily contains silicone. The silicone material allows a sealant to expand easily and contract during changing temperatures without losing its airtight/watertight seal.

Therefore, sealants are a smart choice for areas that experience frequent weather fluctuation and high moisture levels, like kitchens, bathrooms, and around doors and windows.

Oatey tip: The two most important factors to keep in mind when selecting a caulk or sealant are the application site's temperature range and moisture level.

Let’s explore the unique properties and benefits of some of the most common caulks and sealants to ensure you find the best fit for various indoor and outdoor projects.

Types of Caulk and Sealants

Oatey makes various professional-grade caulks and sealants for residential or commercial use. Used on a variety of surfaces and applications, Oatey offers caulks and sealants in silicone, latex, and acrylic formulas.

Here’s an overview of some of the main types of caulk and sealants and their different uses.

1.    Acrylic Latex

Acrylic-latex caulk, also known as latex or general-purpose caulk, is water-based and provides excellent adhesion to most common building materials, including wood. Unlike a silicone sealant, it is paintable once cured, produces fewer fumes, and can be cleaned up with mild soap and water rather than a chemical solvent.

This caulk type is also easier to apply, ideal for hard-to-reach and time-sensitive applications.

However, it’s essential to remember that acrylic-latex caulks provide only a moderate level of water resistance, making them better suited for interior applications without repeated exposure to water. Acrylic-latex caulks can take up to 72 hours to reach full cure.

Oatey Tub N Tile In Use Caulk

Typical plumbing applications for regular and specialty acrylic-latex caulk include:
●    Securing loose tiles.
●    Caulking bathtubs, showers, sinks, and toilets.
●    Sealing crown molding and baseboards.
●    Sealing gaps around plumbing fixtures.

Acrylic-latex caulks to consider:

●    Oatey® Tub-N-Tile Caulk: A white, flexible, latex general-purpose sealant to fill and seal cracks and joints for caulking around tubs, showers, lavatories, and sinks. Tub-N-Tile Caulk cleans up easily with soap and water. The sealant can also be used to reset loose tiles. Once the product is fully cured, it can be painted with an oil base or latex paint. Tub-N-Tile also includes an advanced mildewcide, defending against mildew growth in damp areas.

●    Oatey® Tub-N-Tile Ultra Clear Caulk: A flexible, general-purpose sealant that provides excellent adhesion to most common building materials and can be used for sink and countertop installation, replacing broken ceramic tiles and fixtures, sealing ducts, and exterior air conditioning lines. The product applies white and dries clear in two weeks or less, depending on temperature, humidity, and bead size.

●    Hercules® Firestop Caulk: Intended for multipurpose use, this product is specially designed for firestop applications in small commercial or grouped residential construction and similar structures. Firestop Caulk can be used in systems where dynamic movement can be expected, such as plumbing, HVAC, bath and dryer vents, metallic pipes, non-metallic pipes, conduits and tubing, insulated pipes, electrical and electronic cabling, concrete, gypsum, metal ductwork, and wood floors. It is an intumescent sealant that provides up to a three-hour fire rating and can expand up to 10 times to block flame propagation. It is designed and tested for excellent acoustic performance by reducing noise transmission and sealing smoke.

Hercules Firestop Caulk Sealant

2.    Siliconized Acrylic Latex – Hybrid Caulk

If you’re looking to combine the strong sealing properties of a silicone sealant and the ease of application and cleanup that an acrylic-latex caulk offers, opt for a siliconized acrylic-latex caulk. This hybrid caulk provides a waterproof seal that will not crumble or shrink when temperature changes occur, making it both flexible and durable. It is also made to dry quickly (only 24 hours) and glides smoothly on surfaces for frustration-free shaping and blending.

Typical plumbing applications for regular and specialty hybrid caulk include:

●    Bathtub and shower surrounds.
●    Backsplashes.
●    Sealing exterior siding.
●    Reducing window and door drafts.

Hybrid caulks to consider: 

●    Hercules® Plumbers Caulk™: This commercial-grade, easy-to-use, single-component, non-sag, siliconized acrylic-latex caulk forms a flexible, durable, and UV-resistant (ultraviolet) waterproof seal on interior and exterior surfaces. It flows easily and doesn't crumble or harden in the tube or cartridge. It resists shrinkage and becomes tack-free in one hour. 

●    Harvey™ Siliconized Acrylic Caulk: A water-based acrylic caulk with silicone for added adhesion and low-temperature flexibility, it is tack-free in 30 minutes and paintable in two hours with latex or oil-based paints.

Hercules Plumbers Caulk in Use

3.    Polyurethane Sealant

Polyurethane sealant is multi-purpose and extremely durable. It is an excellent lead substitute for caulking cast iron soil pipe joints (Oakum must be used for this application). This single-component sealant cures rapidly to a firm yet flexible, waterproof and weather-resistant seal.

As a multi-purpose repair product, it can also be used for caulking the perimeters of frame openings, ductwork, wood, or masonry expansion joints and for glazing both inside and out. It also has many uses in the home, construction, automotive, RV, and marine environments.

Common plumbing applications for polyurethane caulk/sealant include:

●    Sealing soil pipes and ductwork.
●    Repairing and caulking interior and exterior perimeters of frame openings and expansion joints and for glazing.
●    Useful in building construction, automotive, RV, and marine applications.
●    Adheres to cast iron, masonry, wood, concrete, stone, metals, plastic, glass, aluminum, tile, vitreous china, and porcelain.

Polyurethane sealant to consider:

Hercules® Plastic Seal™: This single-component polyurethane sealant cures rapidly to a firm yet flexible, waterproof and weather-resistant seal. A multipurpose repair product, it can also be used for caulking the perimeters of frame openings, ductwork, wood, or masonry expansion joints and for glazing both inside and out. It is an odorless sealant that air-dries and is crack-proof, shrink-proof and will not produce any fumes while curing. It has excellent adhesion properties to most common substrates, such as plastic, wood, cast iron, masonry, most metals, tile, concrete, glass, aluminum, vitreous china, and porcelain. When thoroughly dried, it withstands great pressure. Multiple thin layers set faster than a single thick layer. It does not contain any volatile organic compounds (0% VOC) or toluene diisocyanate (TDI).

Hercules Plastic Seal Sealant

4.    100%-Silicone Sealant

This 100%-silicone sealant is ideal for wet exterior applications because it’s extremely weather-resistant and contains antimicrobial properties that will inhibit the growth of mold and mildew. Due to a silicone sealant’s strong adhesiveness, elasticity, and water-resistant properties, it’s an excellent choice for kitchen and bath applications. The sealant is also UV-resistant, which protects against yellowing and allows a seal to last longer when exposed to direct sunlight. Silicone sealant is fast-drying, fully curing within 24 hours.

Common plumbing applications for 100% silicone:

●    Sealing top-mount and under-mount sinks to countertops.
●    Bathtub/shower surrounds, doors, and drains.
●    Sealing gaps and seams in gutters.
●    Filling exterior holes made by nails or screws.
●    HVAC applications.

100%-silicone sealant to consider:

Oatey® Silicone Sealant is a mildew-resistant silicone sealant that can be used on ceramic tiles, tubs, showers, rimless sinks, and plumbing fixtures. This high-performing sealant is resistant to weathering, ozone, UV radiation and thaw/freeze conditions. When fully cured, the USDA recognizes the sealant for use in meat and poultry. It is available in clear and white.

Oatey Tip: Read manufacturer instructions and product recommendations to ensure best practices for safe and effective use.

Oatey Silicone Seal Sealant

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