Sealant vs Adhesive: What’s the Difference and How to Choose the Right Product for Waterproofing Projects

In construction and waterproofing projects, two types of materials are often confused: sealants and adhesives.

While both are essential in building systems, they serve completely different purposes. Choosing the wrong one can lead to:

• leakage issues

• structural failure

• costly repairs

In this article, we will clearly explain the difference between sealants and adhesives, and help you select the right solution for your project — including high-performance products like YHSil-100 neutral silicone sealant and YHbond-125 high strength structural adhesive.

What Is a Sealant?

A sealant is a flexible material used to fill joints and gaps to prevent the passage of:

• water

• air

• dust

• chemicals

Sealants are designed to accommodate movement caused by:

• thermal expansion

• structural movement

• vibration

Key Characteristics of Sealants

• high elasticity

• excellent weather resistance

• waterproof and airtight

• movement accommodation

👉 Sealants are not primarily used for bonding strength, but for sealing performance.

What Is an Adhesive?

An adhesive is used to bond two materials together, creating structural or semi-structural strength.

Adhesives are designed to:

• transfer loads

• hold materials in place

• provide strong bonding

Key Characteristics of Adhesives

• high bonding strength

• load-bearing capability

• durable structural connection

• less flexible than sealants

👉 Adhesives focus on strength, not flexibility.

Sealant vs Adhesive: Key Differences

Why This Difference Matters in Waterproofing

In waterproofing systems, both materials are critical:

• Sealants ensure joints remain watertight

• Adhesives ensure membranes and components stay bonded

👉 Using only one type is not enough for a reliable system.

Recommended Solution: Use the Right Product for the Right Job

🔹 For Sealing: YHSil-100 Neutral Silicone Sealant

YHSil-100 is a high-performance one-component, neutral curing and easy-to-apply sealing material.

Key Benefits:

✔ ±20% movement capability

✔ Excellent UV and weather resistance

✔ Non-corrosive to most substrates

✔ Suitable for both indoor and outdoor applications

Typical Applications:

• Ideal for weathertight joints between substrates such as glass (excluding mirrors), metal (excluding copper), aluminum, and concrete.

• Suitable for non-structural bonding and sealing of joints of awnings, roofs, drainage ditches, doors and windows, billboards, elevators, and small curtain walls of glass, stone, and aluminum.

👉 Ideal for durable, weather-resistant sealing across diverse substrates.

For Bonding: YHBond-125 High Strength Structural Adhesive

YHBond-125 is a one-component 100% neutral curing silicone sealant. Featuring high strength, high elongation, and excellent bonding performance, it can firmly adhere to most building materials without prime coating.

Key Benefits:

✔Single component and simple application

✔Excellent bonding performance for most substrates

✔Outstanding weather resistance and durability

✔Sealing and waterproofing

Typical Applications:

• Weather-sealing and structural bonding of diverse materials including glass, metal, wood, and concrete

• Curtain wall systems of glass, stone, and aluminum, skylights, and metal structures

👉 Ideal where strength and durability are required

How to Choose: Practical Guidelines

Choose a Sealant (YHSil-100) when:

• you need to seal joints or gaps

• movement is expected

• weather resistance is critical

Choose an Adhesive (YHBond-125) when:

• you need strong bonding

• materials must stay fixed

• load transfer is required

Common Mistakes to Avoid

❌ Using adhesive instead of sealant for joints

→ leads to cracking and leakage

❌ Using sealant for structural bonding

→ leads to failure under load

👉 Always match the product to the function.