Planning a Bituminous Roof System Installation?

WHETHER specifying a bituminous roofing system for a residential property or an outbuilding, a well-prepared installation process contributes to the overall performance of the roof. The following considerations are based on established good practice for bituminous systems, including both self-adhesive and torch-on applications.

1. Select a Suitable Roofing System

Material selection should be based on compatibility with the substrate, the intended method of attachment (e.g. torch-applied, self-adhesive, mechanically fixed), and the performance characteristics required for the project.

Key considerations may include:

• Appearance and finish
• Reflective properties for solar exposure
• Anticipated foot traffic or maintenance access
• Exposure to chemicals, where relevant

Roofing materials should be stored according to the manufacturer’s instructions. This typically includes keeping rolls upright, off the ground, protected from moisture, and on a clean, level surface. If any materials become wet in storage, they should be fully dried before use to support correct adhesion and long-term performance.

2. Monitor Weather Conditions and Site Environment

Bituminous roofing membranes are sensitive to environmental conditions during application. It is generally not recommended to install in adverse weather such as rain, frost, or high winds, as this can compromise the integrity of the system.

To avoid water ingress during installation, successive layers should be applied without unnecessary delay. If installation must pause due to weather or the end of the working day, a temporary weatherproof ‘night joint’ should be installed to seal exposed areas until work resumes.

3. Prepare the Deck Thoroughly

Before applying the roofing system, the substrate must be properly prepared. This includes ensuring the deck is:

• Dry and structurally sound
• Smooth and free from sharp edges or protrusions
• Clean of debris, dust, grease, laitance or other contaminants

Priming may be required for certain surfaces before the air and vapour control layer is applied.

4. Ensure Secure Attachment

Wind uplift is a critical consideration in flat roofing. All membrane layers should be firmly bonded to the substrate and to each other in line with tested system guidance. Particular attention should be paid to the perimeter zones and upstands, where pressure from wind forces is often greater.

Where existing and new membranes meet, a fully sealed joint should be formed using a compatible bitumen membrane to maintain continuity and weather resistance.

5. Use Appropriate Equipment and Follow Safety Measures

All application tools and safety equipment should be suitable for professional use and appropriate for the chosen method of installation. For torch-applied systems, safe working practices are essential. This includes having fire extinguishers readily available and using protective clothing such as gloves, flame-resistant footwear, and helmets. First aid kits should also be accessible on site.

Supporting Your Project with Chesterfelt Expertise

Chesterfelt has been supplying high-performance bituminous roofing systems to the UK construction market for over 40 years. Our range includes torch-on, self-adhesive and underlay membranes designed for use in both warm and cold roof applications. Each product is backed by clear, up-to-date technical documentation and installation guidance developed to support safe, effective application in line with industry best practice.

For more details visit the Chesterfelt website.

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