6 Types of Polyurethane: Best for Waterproofing

Written By Adam Paul - Waterproofing Expert

Polyurethane is available in 11 main types. When you choose a polyurethane you should consider important features such as water resistance, adhesion, flexibility, breathability, and UV resistance. The features help to withstand the type of polyurethane outside under extreme environmental conditions. With considering all Aqviz, experts have listed these 6 types of polyurethane as follows.

6 Types of Polyurethane

Water-Based Polyurethane (WBPU)
Oil-Based Polyurethane (OBPU)
Solvent-Based Polyurethane (SBPU)
Aliphatic Polyurethane
Aromatic Polyurethane
Polyurethane Foam (PUF)

1. Water Based Polyurethane (WBPU)

We have observed that water based polyurethane is the most used polyurethane type for surface protection from water and sunlight.

Water based polyurethane (WBPU) is a clear, fast-drying coating made from water as a primary solvent. It provides strong waterproofing by forming a protective layer that resists moisture, stains, and scratches. WBPU offers excellent adhesion and flexibility, allowing it to expand and contract with temperature changes also WBPU can be used for minor structural movement areas due to is flexibility. It is breathable, reducing the risk of trapped moisture that can cause wood warping or mold growth. Unlike oil based polyurethane, WBPU has superior UV resistance, preventing yellowing and surface degradation over time.

Water based polyurethane can be applied on hardwood floors, furniture, cabinets, doors, and trim. It is also suitable for indoor applications where low odor and quick drying are required.

Pros of water based polyurethane:

Water based polyurethane dries quickly
Water based polyurethane has low odor and low VOC content
Water based polyurethane provides excellent UV resistance

Cons of water based polyurethane:

Water based polyurethane is less durable than oil based polyurethane
Water based polyurethane may require multiple coats for better protection
Water based polyurethane is more expensive than oil based polyurethane

2. Oil Based Polyurethane (OBPU)

Oil based polyurethane (OBPU) is a durable coating made from synthetic resins and mineral spirits. Oil based polyurethane provides a strong waterproofing membrane. Hence it is used for sealing surfaces exposed to moisture, humidity, and temperature changes. OBPU forms a thick, flexible barrier that repels water, protects surfaces, and extends material lifespan. It adheres well to wood, concrete, and metal. It prevents water damage, warping, and deterioration. Oil based polyurethane is less breathable. It helps to reduce mold and mildew growth. Its UV resistance helps prevent yellowing, fading, and surface wear from sun exposure.

Due to these important features, oil based polyurethane can be applied on hardwood floors, furniture, marine woodwork, and outdoor decks. Its protective finish enhances the durability of surfaces exposed to humidity and water.

Pros of oil based polyurethane

Oil based polyurethane is highly durable
Oil based polyurethane has excellent water resistance
Oil based polyurethane provides a long lasting finish

Cons of oil based polyurethane

Oil based polyurethane has a slow drying time
Oil based polyurethane has a strong odor
Oil based polyurethane requires mineral spirits for cleanup

3. Solvent Based Polyurethane (SBPU)

Solvent based polyurethane (SBPU) is a high-performance coating made with strong chemical solvents. It provides excellent waterproofing by creating a dense, durable layer that blocks moisture penetration. SBPU offers superior adhesion, flexibility, and chemical resistance, making it ideal for surfaces exposed to harsh conditions. It also has high abrasion resistance, ensuring long-term protection against wear and tear. Unlike water based polyurethane, SBPU is less breathable but delivers a harder, more protective finish.

Solvent based polyurethane can be applied on industrial floors, metal surfaces, marine coatings, automotive parts, and concrete structures. It is widely used in high-traffic areas and environments with extreme exposure to water, chemicals, and UV rays.

Pros of solvent based polyurethane:

Solvent based polyurethane provides a highly durable and tough finish
Solvent based polyurethane has excellent water and chemical resistance
Solvent based polyurethane withstands heavy traffic and harsh conditions

Cons of solvent based polyurethane:

Solvent based polyurethane has a strong odor and high VOC content
Solvent based polyurethane requires proper ventilation during application
Solvent based polyurethane takes longer to dry compared to water based polyurethane

4. Aliphatic Polyurethane

Aliphatic polyurethane is a high-performance coating known for its superior waterproofing, UV resistance, and color stability. It forms a tough, moisture-resistant barrier that protects surfaces from water infiltration, abrasion, and harsh environmental conditions. Unlike aromatic polyurethane, aliphatic polyurethane does not yellow or degrade when exposed to sunlight, making it ideal for outdoor applications. It also offers excellent flexibility, allowing it to expand and contract with temperature changes without cracking.

Due to these important features, aliphatic polyurethane can be applied on outdoor decks, marine coatings, roofing systems, concrete floors, and automotive finishes. Its resistance to fading and weathering makes it a preferred choice for surfaces exposed to direct sunlight and harsh weather conditions.

Pros of aliphatic polyurethane:

Aliphatic polyurethane provides excellent UV and weather resistance
Aliphatic polyurethane maintains color stability without yellowing
Aliphatic polyurethane offers strong waterproofing and abrasion resistance

Cons of aliphatic polyurethane:

Aliphatic polyurethane is more expensive than aromatic polyurethane
Aliphatic polyurethane requires careful application for a smooth finish
Aliphatic polyurethane has a longer curing time compared to other polyurethane types

5. Aromatic Polyurethane

Aromatic polyurethane is a strong, moisture-resistant coating known for its durability and cost-effectiveness. It creates a tough waterproof barrier that protects surfaces from water damage, chemical exposure, and abrasion. This polyurethane has excellent adhesion and flexibility, allowing it to bond well with concrete, metal, and wood. However, unlike aliphatic polyurethane, aromatic polyurethane is not UV-resistant and tends to yellow or degrade when exposed to direct sunlight.

Due to these important features, aromatic polyurethane can be applied on indoor flooring, industrial coatings, waterproof membranes, pipe coatings, and protective linings. Its strength and affordability make it a preferred choice for applications where UV resistance is not a primary concern.

Pros of aromatic polyurethane:

Aromatic polyurethane provides excellent waterproofing and chemical resistance
Aromatic polyurethane is cost-effective compared to aliphatic polyurethane
Aromatic polyurethane has strong adhesion and flexibility

Cons of aromatic polyurethane:

Aromatic polyurethane is not UV-resistant and tends to yellow over time
Aromatic polyurethane may degrade faster when exposed to sunlight
Aromatic polyurethane requires a protective topcoat for outdoor applications

6. Polyurethane Foam (PUF)

Polyurethane foam (PUF) is a lightweight, highly effective waterproofing and insulating material. It expands upon application, forming a seamless, moisture-resistant barrier that prevents water infiltration. PUF has excellent adhesion, allowing it to bond with various surfaces, including concrete, metal, and wood. Its closed-cell structure provides superior thermal insulation while also reducing air leakage. Unlike traditional waterproofing materials, polyurethane foam is both flexible and durable, adapting to structural movements without cracking.

Due to these important features, polyurethane foam can be applied on roofs, walls, foundations, pipelines, and cold storage facilities. Its ability to provide both insulation and waterproofing makes it ideal for energy-efficient buildings and moisture-sensitive areas.

Pros of polyurethane foam:

Polyurethane foam provides excellent waterproofing and thermal insulation
Polyurethane foam expands to create a seamless, airtight seal
Polyurethane foam adheres well to various surfaces without additional adhesives

Cons of polyurethane foam:

Polyurethane foam requires professional application for best results
Polyurethane foam can degrade over time if exposed to UV rays without a protective coating
Polyurethane foam may be more expensive than traditional waterproofing materials