Waterproofing with polyurethane (PU)

**Polyurethane waterproofing is a seamless, UV-resistant, very elastic waterproofing membrane** that is applied with liquid.

It creates a protective layer that resembles rubber when applied to the surface, preventing water from penetrating.

It is particularly well-known for its great flexibility (it can stretch up to 300% or more), which makes it appropriate for expanding and contracting surfaces.

1. Types of Waterproofing using Polyurethane

1. Single-component PU

• Ready to use
• Reacts with moisture in the air
• Simple to apply
• Mostly Utilised for Homes

2. Combination PU

• Consists of resin + hardener
• Mixed before application
• Higher strength and durability
• Used in commercial and industrial projects

2. Properties of polyurethane waterproofing

Form Liquid coating (1-component or 2-component)

Finish Seamless, joint-free membrane

Elasticity Very high, good for cracks

UV resistance Excellent (ideal for open roofs)

Chemical resistance Good

Durability 8–12 years depending on grade

Curing time Fast (4–8 hours between coats)

3. Areas of Utilisation

• Terraces and roofs
• Balconies
• Toilets and bathrooms
• Parking decks and podiums
• External basements
• Water tanks with food-grade PU
• Swimming pools with special PU systems

4. Method of Stage-by-Stage Application

1. Surface Readiness

• Thoroughly clean the surface.
• Get rid of any loose particles, oil, and dust.
• Fix honeycombs and fissures.
• Make sure the area is dry.

2. Application for Primer

• Apply PU-compatible primer
• enhance adhesion
• Let the primer cure for four to six hours

3. Use of PU Coating

• Use a roller, brush, or spray to apply the first coat.
• If necessary, use fibreglass mesh to reinforce joints and corners.
• After 6 to 24 hours, apply the second layer.

4. Curing

• It takes 24 to 48 hours to fully cure.
• Keep dry while curing.

5. Pros

• Seamless waterproof layer
• Highly flexible (bridges cracks up to 2 mm)
• UV resistant (especially aliphatic PU)
• Excellent adhesion to concrete, tiles, and metal
• Long service life (10–15 years)
• Suitable for complex shapes and details

6. Cons

• Costlier than cementitious and bituminous methods
• Requires skilled application
• Sensitive to moisture during application
• Not suitable for damp surfaces (unless moisture-tolerant PU is used)

7. Most Suitable For

• Flat roofs with movement
• Areas exposed to sunlight and rain
• Premium residential and commercial buildings
• Repair work is required where a seamless coating is needed.

Contact GK Home Construction

Website: **https://gkhomeconstruction.com/**

Email : care@gkhomeconstruction.com

Call us at : +91 9538999535

(For complete planning, professional guidance, and smooth execution of your home construction project ,Contact now)