APP Modified Bitumen Membrane – Heat-Resistant Waterproofing Solution

APP Modified Bitumen Membrane

APP modified bitumen membranes are polymer-enhanced waterproofing sheets that protect roofs, terraces, and foundations from heat and water. By blending bitumen with atactic polypropylene (APP), they gain excellent resistance to UV rays, high temperatures, and aging — making them ideal for hot climates.

What Is an APP Modified Bitumen Membrane?

An APP modified bitumen membrane is a roll waterproofing sheet made from bitumen mixed with APP polymer. The polymer raises the softening point and improves UV and weathering resistance. When applied by torch or heat, it forms a seamless, durable, and watertight layer for both exposed and protected surfaces.

Composition and Structure

Top Finish

Mineral granules, aluminum foil, or sand film for UV and mechanical protection.

Bituminous Compound

APP-modified bitumen core ensures excellent heat and UV stability.

Reinforcement Layer

Polyester or fiberglass mat for tensile strength and flexibility.

Bottom Film

Polyethylene layer that melts during torching to bond with the substrate.
Self-adhesive options are available for flame-restricted areas.

Key Advantages

• Superior heat and UV resistance.

• Stable dimensions; resists tearing or deformation.

• Long lifespan on exposed roofs.

• Works on roofs, terraces, and foundations.

• Easy local repairs with APP patches.

Limitations

• Less flexible in very cold weather than SBS types.

• Needs skilled torch application and fire safety.

• Requires clean, primed surfaces for best adhesion.

Typical Applications

• Flat and low-slope roofs in hot areas

• Re-roofing over bituminous layers

• Foundations, retaining walls, and basements

• Balconies and terraces with screed or tiles

• Industrial and commercial roofs

Installation Overview

1. Clean and prime surface.

2. Torch bottom face until bitumen melts, press for bonding.

3. Overlap joints 8–10 cm (sides), 12–15 cm (ends).

4. Seal corners and penetrations carefully.

5. Use self-adhesive type where open flame isn’t allowed.

Maintenance and Service Life

Inspect twice a year, keep outlets clear, and repair small damage promptly.
With proper care and installation, APP membranes typically last 20 years or more.

APP vs SBS – Quick Comparison

Technical Data (Typical)

• Thickness 3–5 mm (4–5 mm for exposed roofs)

• Reinforcement polyester or fiberglass

• Roll size ≈ 1 m × 10 m

• Softening point > oxidized bitumen

• Top finish mineral / aluminum / sanded

FAQ

What is APP membrane?
A polymer-bitumen sheet modified with APP for superior heat and UV resistance.

When to use APP or SBS?
Choose APP for hot climates, SBS for cold regions.

Is it UV-resistant?
Yes — designed for exposed roofs.

How thick should it be?
Usually 4–5 mm for exposed areas.

How long does it last?
Over 20 years with proper installation.