Downspout Roll Forming Materials: Steel, Aluminum & Pipe Coil Guide

Downspout Roll Forming Materials

1. Overview of Downspout Materials in Roll Forming

Downspout roll forming materials are used to produce rainwater pipes and drainage systems, including rectangular, square, and round downpipes.

These materials must provide:

Corrosion resistance
Formability for tight bends
Structural integrity for vertical installation
Good surface finish for visible applications

Downspout materials are typically lighter gauge than structural steel but require better forming quality than standard roofing materials.

2. Main Types of Downspout Materials

1. Aluminum (Most Popular)

Lightweight and easy to form
Excellent corrosion resistance
Used in seamless gutter + downpipe systems

2. Painted Aluminum

Pre-coated for aesthetics
Common in residential applications

3. Galvanized Steel (GI)

Stronger than aluminum
Zinc coating for corrosion protection
Used in commercial systems

4. Pre-Painted Steel (PPGI)

Color-coated steel
More rigid than aluminum
Cost-effective

5. Stainless Steel

High corrosion resistance
Used in industrial or coastal environments

6. Copper

Premium architectural material
Long lifespan

7. Zinc

Self-protecting surface
Used in high-end architectural systems

3. Material Composition & Structure

Aluminum-Based Materials

Aluminum core (3003 / 3004 common)
Optional paint coating

Steel-Based Materials

Steel core
Zinc coating (GI) or paint coating (PPGI)

Premium Materials

Copper (solid metal)
Zinc (natural patina-forming surface)

4. Available Coil Specifications

Thickness Range

0.4mm – 1.0mm

Coil Width

150mm – 400mm (depends on pipe size)

Coil Weight

1 ton – 5 tons

Coil ID / OD

ID: 300mm / 508mm
OD: up to 1200mm

5. Mechanical Properties

Typical values:

Yield Strength: 100 – 400 MPa
Tensile Strength: 150 – 500 MPa
Elongation: 15% – 30%

👉 Aluminum = more flexible
👉 Steel = stronger but less formable

6. Coating Types for Downspout Materials

Paint Coatings

PE (Polyester)
SMP
PVDF

Zinc Coating (Steel)

Z100 – Z275

Natural Materials

Copper and zinc form protective layers naturally

7. Surface Finishes

Gloss finish
Matte finish
Textured finish
Painted finish
Mill finish (aluminum)

8. Common Downspout Profiles Produced

Rectangular downpipes
Square downpipes
Round downpipes
Corrugated downpipes
Decorative rainwater pipes

9. Advantages of Downspout Materials

Excellent corrosion resistance
Lightweight (aluminum)
Easy to form
Good aesthetic finish
Suitable for outdoor use

10. Disadvantages / Limitations

Aluminum can dent
Steel may rust if coating is damaged
Surface scratching during forming
Limited thickness range
Copper and zinc are expensive

11. Roll Forming Machine Considerations

Roll Tooling

Smooth rollers required
Chrome rollers recommended

Speed

10–25 m/min

Lubrication

Usually not required for painted materials

Cutting

Flying shear or hydraulic cutting

Common Issues

Paint damage
Profile distortion
Seam alignment issues

12. Common Problems in Production

Scratches on painted surface
Seam opening or misalignment
Uneven forming
Coil camber
Denting in aluminum

13. Pricing Guide

Typical global pricing:

Aluminum: $2000–$3500/ton
Painted Aluminum: $2500–$4000/ton
GI Steel: $700–$1100/ton
PPGI Steel: $900–$1400/ton
Stainless Steel: $2000–$5000/ton
Copper: $8000–$12000/ton
Zinc: $4000–$7000/ton

Factors affecting price:

Material type
Coating
Thickness
Market demand

14. Comparison of Downspout Materials

Aluminum vs Steel

Aluminum = lightweight, corrosion resistant
Steel = stronger, more rigid

PPGI vs Painted Aluminum

PPGI = cheaper
Aluminum = better corrosion resistance

Stainless vs GI

Stainless = premium corrosion resistance
GI = cost-effective

15. Best Industries Using Downspout Materials

Residential roofing
Commercial buildings
Industrial facilities
Prefabricated buildings
Architectural projects

16. How to Choose Downspout Material

Choose Based On:

Climate (rain, coastal, corrosion)
Budget
Aesthetic requirements
Installation method

General Guide:

Residential → Aluminum
Commercial → PPGI / GI
Coastal → Stainless / Aluminum
Premium → Copper / Zinc

17. FAQ Section

What is the best material for downspouts?

Aluminum is the most commonly used.

What thickness is used?

Typically 0.4mm–1.0mm.

Can downpipes be roll formed?

Yes, all standard downpipes are roll formed.

Do painted materials crack?

They can if bent too tightly.

What is the cheapest option?

Galvanized steel.

18. Machine Matcher Section

We supply roll forming machines for all downspout materials.

Rectangular and round pipe machines
Seam forming systems
High-speed production lines
Custom-built solutions
Global delivery available
UK and USA technical support

Contact:
Machine Matcher
Sales & Technical Team

Quick Specs

Thickness
0.4–1.0mm

Yield Strength
100–400 MPa

Coil Width
150–400mm

Coil ID
300 / 508mm