Choosing a Roof Waterproofing Membrane for Commercial and Industrial Buildings

There is no single roof waterproofing membrane system that is automatically best for every building. A factory roof with large open concrete areas has different requirements from a high-rise roof crowded with services, pipes, plinths, and drainage details.

The right decision starts with the building—not with a product name. Property owners, consultants, and facility managers should consider the following factors before selecting a system.
1. Building type and roof use
Commercial and industrial roofs may support air-conditioning equipment, water tanks, exhaust systems, solar equipment, access walkways, and maintenance activities. The frequency of foot traffic and the risk of mechanical damage affect the type of membrane and protection required.

An exposed roof that is rarely accessed may have different needs from a plant roof where technicians work regularly.
2. Roof size and complexity
Torch-applied membrane is commonly considered for large concrete roof areas because reinforced sheets can create a robust waterproof barrier. However, sheet systems require well-formed laps and skilled detailing.

Liquid-applied membrane forms a continuous coating and can adapt well to irregular roof shapes, corners, pipes, drains, and equipment bases. The finished performance depends on proper preparation, sufficient coverage, reinforcement where required, and full curing.

Rather than choosing solely on general advantages, ask which system can be installed and detailed most reliably on the actual roof.
3. Condition of the existing substrate
The current roof may contain cracks, damp areas, failed coatings, debonded screed, old membrane, or several layers of previous repairs. Installing a new system without addressing these conditions can trap moisture or transfer defects into the new work.

A site assessment should determine what must be removed, repaired, dried, or levelled before application.
4. Drainage and ponding
Waterproofing and drainage must work together. Blocked outlets, inadequate falls, and low points can leave water standing on a flat roof after rain.

The proposed membrane should be suitable for the roof’s exposure, but persistent ponding should also be addressed where practical. Otherwise, the waterproofing system will remain under unnecessary stress.
5. Structural and thermal movement
Concrete roofs move as temperatures change, and joints are designed to accommodate movement between building elements. A waterproofing proposal must consider these conditions, especially at expansion joints, cracks, parapets, and transitions between materials.

Membrane flexibility is important, but correct joint detailing is equally critical. Simply coating over an active joint may not provide a durable solution.
6. Installation safety and building operations
Torch-applied systems involve hot work and require trained installers, permits, fire controls, and careful planning. Some occupied or sensitive sites may favour a cold-applied system, subject to the roof condition and specification.

The project plan should also consider access, odour, noise, material movement, work zones, weather, and the building’s operating hours.
7. Whole-life value
The lowest quotation is not always the lowest-cost solution. Compare the full scope, including preparation, repairs, membrane specification, detailing, protection, safety provisions, quality checks, warranty, and after-sales support.

An incomplete proposal may appear cheaper because important preparation or detailing has been excluded. Clear scope and workmanship standards make quotations easier to compare fairly.
Questions to ask before approving a system
What is causing the existing leakage?
Which areas will be removed or repaired?
Why is the recommended membrane suitable for this roof?
How will drains, joints, parapets, and penetrations be treated?
What quality checks will be carried out?
What is included in the warranty?
What maintenance will be required after handover?

Pan Asiatic Enterprise Sdn. Bhd. provides torch-applied and liquid-applied waterproofing membrane solutions for commercial buildings, factory concrete roofs, industrial buildings, high-rise properties, and membrane roofing projects in Malaysia. Its work is supported by strict quality control and warranties.

Call to action: Arrange a site assessment with Pan Asiatic to identify the most suitable waterproofing system for your roof conditions and operational needs.