Balcony and roof terrace detailing has traditionally relied on a simple assumption: that structural elements such as balustrades must be fixed directly into the building structure, even when that means penetrating the waterproof membrane.
In practice, this creates a tension between two critical requirements. On one hand, balustrades must resist structural loads from occupants and wind. On the other, waterproofing systems rely on continuity to perform reliably over time.
Introducing penetrations through the membrane interrupts that continuity. While sealants, collars and flashings are used to maintain watertightness, these elements often operate on a shorter lifecycle than the membrane itself and are exposed to movement, weathering and structural forces.
For roof terraces constructed above habitable space, this detail becomes particularly significant. Failures are often hidden beneath finishes, making inspection difficult and remediation disruptive if issues arise.
As a result, many designers are now reconsidering whether penetrative detailing is the most robust long-term approach.
Non-penetrative systems offer an alternative by separating structural load transfer from the waterproofing layer. Rather than anchoring balustrades through the membrane, loads are distributed across an engineered structure positioned above it, allowing the membrane to remain continuous.
At Balconette, the BalcoDeck system was developed to support this approach, enabling terraces to meet structural and safety requirements without introducing penetrations through the waterproofing layer.
Read the full article on Balconette here to explore the lifecycle implications of penetrative vs non-penetrative detailing:
