🛠️ Sheet Membrane vs Liquid Membrane: What’s Best for Waterproofing Your Balcony?

planab55
Aug 3, 2025
3 min read

Updated: Aug 9, 2025

If you own or manage an apartment building on the Northern Beaches of Sydney, you're probably aware of how important it is to have a reliable, long-lasting waterproofing system—especially on balconies exposed to harsh coastal conditions.

At Plan A Builders, we specialise in remedial building works for multi-residential buildings, and one of the most common questions we’re asked is:What’s better for balcony waterproofing—sheet membrane or liquid membrane?

Let’s break it down to help you make an informed decision.

📍 Why Waterproofing Is Crucial on the Northern Beaches

Suburbs like Manly, Dee Why, Collaroy, and Mona Vale experience:

Salt-laden air that corrodes structures
High rainfall and heavy downpours
Strong UV exposure
Buildings often constructed in the 70s–90s with outdated systems

These factors put tremendous pressure on older balconies, especially if they haven’t been properly maintained. When waterproofing fails, the result is often leaks into lower units, concrete cancer, and costly damage.

That’s where the choice between sheet membranes and liquid membranes becomes critical.

🔍 What Is a Liquid Membrane?

Liquid membranes are paint-on or roller-applied coatings that form a flexible, seamless waterproof barrier when dry.

Pros of Liquid Membranes:

Easier to install on irregular or tight spaces
Seamless finish with no overlaps
Faster installation for small areas
Flexible under minor movement or vibration

Cons of Liquid Membranes:

Thickness can vary depending on application technique
Can be more prone to failure if not applied correctly
Not as durable in high-traffic or exposed areas
UV exposure can degrade some products

🧱 What Is a Sheet Membrane?

Sheet membranes are pre-formed rolls of waterproof material (like bitumen or PVC) that are laid out and heat-fused or adhered to the surface. They're widely used in commercial and strata remediation.

Pros of Sheet Membranes:

Consistent thickness and quality (factory-controlled)
Greater tear resistance and durability
Long-lasting under foot traffic and sun exposure
Preferred for large, flat balcony areas
Easier to inspect post-installation

Cons of Sheet Membranes:

Requires a clean, smooth substrate
Installation is more labour-intensive
Overlaps must be carefully sealed to avoid leaks

⚖️ Which Is Better for Your Balcony?

Feature	Liquid Membrane	Sheet Membrane
Installation	Quicker for small spaces	Longer, more precise
Durability	Moderate	High
UV Resistance	Varies by product	Excellent
Crack Bridging	High flexibility	Moderate, depends on product
Traffic Resistance	Moderate	High
Application Consistency	Variable (manual)	Consistent (factory made)

✅ Our Recommendation for Northern Beaches Apartments:

For multi-residential balconies, especially those with high exposure or past water issues, we typically recommend sheet membrane waterproofing for its long-term durability and reliability.

In some smaller or more complex balcony areas, a hybrid approach using both sheet and liquid products may be ideal.

🏢 Real-World Example: Balcony Remediation in Manly

Plan A Builders was engaged to remediate leaking balconies in a four-storey apartment complex in Manly. The original waterproofing (liquid membrane) had broken down after just a few years. We:

Removed the old tiles and screed
Installed a high-performance bitumen sheet membrane system
Rebuilt the screed with correct fall
Re-tiled and provided full compliance documentation

The result? No more leaks and a 7-year waterproofing warranty.

🧰 Why Choose Plan A Builders?

✔ Licensed remedial builders with expertise in strata✔ Specialising in waterproofing systems for balconies✔ Servicing Northern Beaches Sydney✔ Work in line with Australian Standards and NCC✔ Transparent quoting and photographic reporting✔ HBCF (Home Building Compensation Fund) cover where applicable

📞 Get Expert Waterproofing Advice for Your Building

If you're unsure whether your balconies need sheet membrane, liquid membrane, or both, our team can provide a professional assessment and report tailored to your building’s condition.

📲 Craig Chamberlin – 0429 030 851📧 craig@planabuilders.com.au🌐 www.planabuilders.com.au