Roof Sheeting
Rooftech Manufacturing & Supply Specifications
All roof sheeting manufactured and supplied by Rooftech is produced from high-tensile steel and high-grade polycarbonate formulations in strict compliance with SANS 10214 (Structural use of steelwork in buildings) and SANS 10400 (National Building Regulations).
Profile Comparison Overview
| Feature / Profile | IBR Profile | Corrugated Profile | Polycarbonate Profile |
| Profile Type | Inverted Box Rib (Trapezoidal) | Traditional Sinusoidal Wave | Translucent Rib / Wave Profile |
| Cover Width | 686 mm | 762 mm | Matches IBR (686 mm) or Corrugated (762 mm) |
| Rib Height / Depth | 36 mm rib height | 17.5 mm wave depth | 36 mm (IBR profile) / 17.5 mm (Corrugated) |
| Min. Roof Pitch | 5° (3° with sealed lap joints) | 10° | Matches underlying metal profile |
| Material Options | Galvanized, Chromadek®, Zincalume® | Galvanized, Chromadek®, Zincalume® | UV-Stabilized Polycarbonate |
| Primary Application | Commercial, Industrial & Modern Residential | Residential, Agricultural & Curved Roofing | Skylights, Pergolas, Industrial Daylighting |
Detailed Profile Specifications & Span Tables
A. IBR Profile (Inverted Box Rib)
The IBR profile is a deep-ribbed trapezoidal sheet designed for maximum strength, water run-off efficiency, and structural economy over wider purlin spans.
Technical Cross-Section & Dimensions Diagram
┌───┐ ┌───┐ ┌───┐
│ 36mm │ │ │ │
──┘ └─────────────────┘ └─────────────────┘ └───
|<----------- 686mm Effective Cover Width ----------->|
IBR Recommended Purlin Span Tables
Max recommended centers in millimeters based on standard wind load zones:
| Thickness (Gauge) | Weight (kg/m2) | Roof Purlin Spacing (Max) | Wall Cladding Spacing (Max) | Overhang (Max) |
| 0.47 mm ISQ550 | ~4.3 $kg/m^2$ | 1,200 mm | 1,500 mm | 150 mm |
| 0.50 mm ISQ550 | ~4.6 $kg/m^2$ | 1,400 mm | 1,750 mm | 200 mm |
| 0.58 mm ISQ300 | ~5.3 $kg/m^2$ | 1,700 mm | 2,100 mm | 250 mm |
| 0.80 mm ISQ300 | ~7.2 $kg/m^2$ | 2,200 mm | 2,600 mm | 300 mm |
B. Corrugated Profile (762mm Cover)
The traditional round-corrugated profile provides high aesthetic appeal, flexibility for curved roofing architectures, and proven structural resilience.
Technical Cross-Section & Dimensions Diagram
╭─╮ ╭─╮ ╭─╮ ╭─╮ ╭─╮ ╭─╮ ╭─╮ ╭─╮ ╭─╮
──╯ ╰───╯ ╰───╯ ╰───╯ ╰───╯ ╰───╯ ╰───╯ ╰───╯ ╰───╯ ╰──
|<----------------- 762mm Effective Cover Width ----------------->|
(Pitch: 76mm | Depth: 17.5mm)
Corrugated Recommended Purlin Span Tables
| Thickness (Gauge) | Weight (kg/m2) | Roof Purlin Spacing (Max) | Wall Cladding Spacing (Max) | Overhang (Max) |
| 0.47 mm ISQ550 | ~4.1 $kg/m^2$ | 1,000 mm | 1,200 mm | 120 mm |
| 0.50 mm ISQ550 | ~4.4 $kg/m^2$ | 1,150 mm | 1,400 mm | 150 mm |
| 0.58 mm ISQ300 | ~5.1 $kg/m^2$ | 1,350 mm | 1,600 mm | 200 mm |
C. Polycarbonate Translucent Profile
Co-extruded with high-performance UV protection layers to allow up to 85% natural light transmission while shielding against harsh UV radiation and weathering.
Technical Specifications
Light Transmission: Clear (85%), Opal White (45%), Bronze (35%)
Service Temperature Range: -40°C to +120°C
Fire Rating: Class 1 / SANS 10177 Compliant (Self-extinguishing)
Profiles Available: Profile-matched to standard IBR (686mm) and Corrugated (762mm) for seamless integration into metal roofs.
Polycarbonate Recommended Purlin Spans
| Sheet Thickness | Recommended Purlin Spacing | Fastener Requirement |
| 1.0 mm | Max 900 mm | Class 4 Self-drilling screws with EPDM bond washers (Oversize pre-drilled clearance hole required for thermal expansion) |
| 1.2 mm | Max 1,000 mm | |
| 1.5 mm (Heavy Duty) | Max 1,200 mm |
Fastening & Installation Guidelines
Thermal Expansion: Polycarbonate and metal sheets expand and contract with temperature shifts. Always pre-drill thermal expansion clearance holes (10mm for polycarbonate) prior to securing fasteners.
Fastener Selection:
Wood Purlins: Class 4 12 x 65mm Hex Head Wood Screws with EPDM Washers.
Steel Purlins: Class 4 12 x 55mm Self-Drilling Tek Screws with EPDM Washers.
Flashing & Sealing: All ridge caps, side lap seals, and valley flashings must be installed using high-grade neutral cure silicone sealant and butyl tape conforming to SANS structural waterproofing guidelines.
Your roof is an essential part of your home. Done professionally, it seals your house, protects it from water leaks and increases your property value. Most importantly, your roof brings your home to life for many years to come.
At Rooftech, we know the value of your roof and what it means for your home. Since we began roofing in Cape Town almost a decades ago, we have witnessed every issue that can occur in roofing.
From our years of experience in roofing, we know that it’s important to choose the right product for your unique property needs. While there are many roofing materials available, COLORBOND® and ZINCALUME® are two of the most popular.
Designed by a specialist steel company, these two durable forms of roofing have become some of the most attractive in today’s market. When it comes to deciding which product to use, understanding how they differ and the advantages and disadvantages of each can help.
To help you choose the best option for your roof, here’s everything you need to know about Colorbond and Zincalume.
WHAT IS COLORBOND® ROOFING?
Secure, durable and energy smart, Colorbond steel is a popular roofing material. Created in the mid-nineteenth century, Colorbond was the solution to corrugated roofs. While corrugated roofs were robust, they corroded easily so needed regular painting. In response, Colorbond steel was created as a better alternative.
Since its introduction in South Africa in 1976, Colorbond has become one of the most attractive roofing options. As a pre-painted steel material with a Zincalume core, Colorbond is strong yet lightweight. Manufactured by BlueScope Steel Limited, strict design, manufacturing and testing procedures are followed to ensure it is built to last.
With its long lifespan, Colorbond steel is used on roofs across South Africa. Available in a wide range of colours, the product is thermally efficient, highly resistant to corrosion and easy to maintain. Offering exceptional benefits, it’s no wonder that Colorbond steel has become a popular roofing material.
WHAT IS ZINCALUME® ROOFING?
Tough, reliable and durable, Zincalume steel is another popular roofing material. Made from zinc, aluminium and silicon, this product lasts four times longer than galvanised steel. Since its introduction in South Africa in the 1970s, it has been used in many properties across the country.
Also manufactured by BlueScope Steel Limited, Zincalume steel undergoes extensive testing. Over the last 17 years, more than 5,000 Zincalume steel panels have been tested in real-world conditions. The panels’ resistance to all elements proves that Zincalume is one of the toughest steel materials available.
Zincalume steel also offers long-lasting performance. Like Colorbond, it is thermally efficient, highly resistant to corrosion and easy to maintain. As one of the most durable and economic forms of roofing, it is a popular choice for South African roofs.
Since your roof is a long-term investment, it’s important to choose the best option for your home. While Colorbond and Zincalume are both strong, durable and long-lasting, there is a key difference that you should consider.
The key difference between Colorbond and Zincalume is, in fact, colour. While Colorbond is available in 22 colours, Zincalume comes in one standard aluminium colour. This difference can impact the look and appeal of your home.
Colorbond’s wide range of colours has been designed to suit all styles. Inspired by South Africa, the colours are grouped into contemporary, classic, matt and ultra palettes. Whether you prefer cool, warm, light, dark, subtle or bold shades, Colorbond has colours to match your home’s theme or help you create it.
On the other hand, Zincalume steel comes in one standard aluminium colour. Since it does not have a layer of custom paint, its colour cannot be tailored to your home’s theme. Its shiny metal look also dulls over time, which may detract from your home’s appeal.
When it comes to choosing the best roofing option for your home, you need to decide whether colour is important. The fact that one product can come in colours to suit your home and the other cannot is a factor that you should consider.
ADVANTAGES AND DISADVANTAGES OF COLORBOND®
To help you decide whether it is the best option for your roof, here are the main advantages and disadvantages of Colorbond roofing in Cape Town.
ADVANTAGES OF COLORBOND®
Resistant in All Weather Conditions
Tested in South African conditions, Colorbond roofing is weather-resistant. Whether it is extreme heat, cold, rain or wind, this product can withstand it all. It is even compliant for use in bushfire prone areas. Undergoing extensive corrosion, durability and exposure testing, Colorbond steel is strong and secure, no matter the weather.
Durability
Colorbond roofing is incredibly durable, this roofing material is built to last. Each layer offers added strength, protection and technology that increases the product’s durability.
Colour And Design Range
Colorbond’s wide range of colours and designs let you customise your roof to your home. Available in 22 contemporary, classic, matt or ultra shades, there is a colour to suit every theme. Colorbond is also available in a variety of designs, including corrugated, panel and weatherboard. These options allow you to match your roof to your unique property needs.
Energy Efficient
This roofing material improves your home’s energy efficiency. Featuring Thermatech® technology that reflects the sun’s rays, it helps keep your home cool, so you use your air conditioner less. What’s more, choosing the highly energy-efficient lighter roof colours may qualify for a roof insulation concession.
Low Maintenance And Long Life
Colorbond roofing’s durability means that it is easy to maintain and long-lasting. Simply washing it with water every so often is enough to maintain its look. If maintained properly, your Colorbond roof can last at least 30 years.
DISADVANTAGES OF COLORBOND®
Colorbond Roofing Cost
The main disadvantage of Colorbond roofing in Cape Town is its cost. Aside from installation and labour costs, the Colorbond roofing cost can be higher than other options.
The Colorbond roofing cost varies depending on the type of roof sheets you need. For example, Colorbond roof sheets with enhanced durability cost more than basic corrugated sheets.
While the Colorbond roofing cost needs to be considered, it is important to remember this product’s superior quality and long life. With its low maintenance, you will also save more in the long run. Your roof needs to keep your home safe and secure, so investing in Colorbond steel ensures this protection for many years.
ADVANTAGES AND DISADVANTAGES OF ZINCALUME®
To help you decide whether it is the best option for your roof, here are the main advantages and disadvantages of Zincalume roofing.
ADVANTAGES OF ZINCALUME®
Toughness
Zincalume is one of the toughest steel products available. Its zinc, aluminium and silicon components make it exceptionally durable. Highly resistant to corrosion and scratching, this roofing material is not easily damaged.
Long Lifespan
Its incredible toughness also gives it a long lifespan. Developed after extensive research into improving galvanised steel, Zincalume’s components ensure long-lasting performance. In fact, Zincalume steel lasts four times longer than galvanised steel.
More Affordable
Zincalume roofing is an affordable option that still delivers results. Strong, lightweight, non-combustible and resistant in all weather conditions, it offers many benefits at a lower price compared to some roofing materials.
DISADVANTAGES OF ZINCALUME®
Standard Aluminium Colour
Zincalume’s standard aluminium colour is a significant disadvantage. Since it does not have a layer of custom paint, this product only comes in one colour. This means that the material cannot be tailored to your home’s theme. Prone to dull over time, its shiny metal colour can also detract from the look and appeal of your home.
Less Energy Efficient
Due to its shiny metal colour, Zincalume steel is less energy efficient than some roofing materials. The steel sheeting is so shiny that it naturally radiates heat. As a result, your home can also become less energy efficient.
WHICH IS THE BEST OPTION FOR YOUR ROOF?
As two of the most popular roofing materials, COLORBOND® and ZINCALUME® differ in many ways. When it comes to deciding which option is best for your roof, you should consider your unique property needs and the advantages and disadvantages of each product.
While both roofing materials are incredibly durable, if you are seeking superior quality, you can’t go wrong with Colorbond steel. Even though the initial outlay is higher than Zincalume’s, Colorbond’s customisable colour, low maintenance and long life make it a great investment for the long run. Choosing Colorbond roofing will not only add value to your property but bring your home to life for many years to come.
If you are looking for Colorbond roofing installation or Colorbond roof replacement in Cape Town, we provide a fully comprehensive range of services tailored to your property. At Rooftech, we understand how important your home is to you, which is why we take the time to get to know your requirements.
When it comes to Colorbond roofing in Cape Town, we provide the highest standards of craftsmanship, safety and service. If you are looking for a roofing in Cape Town, our team can assess your needs and give you a roofing quote.
For a no-obligation discussion on Colorbond roofing installation, Colorbond roof replacement or roof plumbing, contact us today on +27 21 207 3872
Do you have any questions about the differences between Colorbond and Zincalume? Want to know more about these steel roofing options?