Is a roofing membrane waterproof?
Roofing membranes vary in their properties, with some offering full waterproofing and others designed primarily for breathability. Waterproof roofing membranes create an impermeable barrier that prevents water ingress, making them suitable for flat roofs, low-pitched roofs, or areas prone to heavy rainfall. These membranes are often fully bonded or sealed to prevent leaks.
In contrast, breathable membranes allow controlled vapour diffusion, helping to manage moisture levels within the roof space. This is particularly beneficial in pitched roofs where airflow and ventilation are important for preventing condensation. The choice of membrane depends on the roof’s design, exposure to weather, and the need for moisture management. In many cases, combining a breathable membrane with additional waterproofing elements provides the best long-term performance.
Is a breathable roof membrane waterproof?
A breathable roof membrane provides a protective layer that allows water vapour to escape while resisting liquid water penetration. This helps reduce condensation build-up within the roof structure, minimising the risk of damp and mould. However, a breathable membrane alone does not offer complete waterproofing. It is designed to work alongside other roofing materials, such as tiles or metal sheeting, to create a weather-resistant system. For roofs exposed to high levels of moisture or extreme weather, additional waterproofing layers, such as underlays or fully sealed membranes, may be required to ensure complete protection.
Can you use roofing membranes on walls?
Yes, in some cases, roofing membranes can be used on walls, but it depends on the type of membrane and the specific requirements of the structure.
- Breathable Roofing Membranes – Many modern breathable roofing membranes can also be used on external walls to provide a protective layer against moisture while allowing vapour to escape. This helps prevent condensation within timber-framed buildings and improves overall durability.
- Waterproof Roofing Membranes – Fully waterproof roofing membranes are generally not suitable for walls, as they do not allow moisture to escape. Using a non-breathable membrane on walls could lead to trapped condensation, potentially causing damp and structural damage.
- Installation Considerations – If a roofing membrane is being used on walls, it must be installed correctly, with appropriate overlaps, sealing, and ventilation measures to ensure effective moisture management.
For best results, it’s advisable to use membranes specifically designed for wall applications, such as vapour control layers or breathable wall wraps, to ensure optimal performance and longevity.
How to install damp proof membrane on...
Concrete Floors:
- Ensure the concrete surface is clean, dry, and level before installation.
- Roll out the membrane across the floor, ensuring it overlaps at the seams.
- Use a suitable adhesive or waterproof tape to seal any overlaps and edges.
- Extend the membrane slightly up the walls to create a sealed barrier.
- Secure the floor covering or screed on top of the membrane to complete the installation.
On Walls:
- Position the membrane over the wall surface, covering the entire area.
- Secure it using mechanical fixings or an adhesive suitable for the surface type.
- Overlap sections to ensure continuous coverage and seal the joints effectively.
- Apply a protective layer, such as plasterboard or timber cladding, over the membrane to complete the wall system.
