The main waterproofing area can be installed perfectly.
But a roof does not usually fail in the middle of a large, uninterrupted membrane.
It fails at the details.
Corners.
Outlets.
Penetrations.
Kerbs.
Thresholds.
Parapets.
Termination points.
Changes in material or direction.
These areas are more complex because several risks often come together in one small location:
- Movement
- Changes in direction
- Multiple materials
- Mechanical fixings
- Difficult access
- Water concentration
- Limited space for correct installation
A small detailing mistake can create a much larger problem.
A small mistake can create a system-level failure.
Typical failures include:
- Poorly formed internal or external corners
- Insufficient reinforcement
- Incorrect membrane overlaps
- Weak termination points
- Gaps around penetrations
- Poorly sealed outlets
- Incompatible materials
- Waterproofing applied where movement has not been considered
Good detailing is not simply about adding more material.
It is about understanding how water moves, how the building moves and how the waterproofing system should respond.
Before completing any detail, we should ask:
- Where can water collect?
- Where can movement occur?
- Are different materials meeting here?
- Does the detail need reinforcement?
- Is the termination secure?
- Can the area actually be installed and inspected properly?
A roof may contain thousands of square metres of waterproofing.
But its performance can depend on a detail only a few centimetres wide.
The membrane protects the roof.
The details determine whether it survives.