1. Introduction to mechanical resistance
The mechanical resistance of glass blocks is a fundamental performance factor to ensure the safety, durability, and stability of glass walls. Unlike monolithic glass, the glass block is a hollow, pressed, sealed, and reinforced element designed to:
- support its own weight
- resist horizontal loads (wind, accidental impacts)
- distribute stresses through the mortar and reinforcement
- maintain stability over time
Mechanical resistance does not depend solely on the glass block, but on the complete system, which includes:
- glass blocks
- mortar
- reinforcement
- joints
- wall geometry
- supporting structure
2. Mechanical parameters of the glass block
Typical mechanical values of glass blocks include:
2.1 Compressive strength
Glass blocks present average values of:
- 300–350 N/mm² (single block)
- 40–45 N/mm² (bonded block or integrated in a wall)
These values derive from standard tests EN 1051-1 / EN 1051-2 and confirm that the glass block is highly resistant to compression, but not designed for structural vertical loads.
2.2 Flexural strength
The glass block is not designed to resist autonomous flexural loads. Flexural resistance is provided by the installation system, which includes:
- horizontal reinforcement
- vertical reinforcement
- structural mortar
- properly dimensioned joints
2.3 Impact resistance
Glass block walls are classified as:
- non-load-bearing walls
- walls resistant to accidental impacts (people, light objects)
- walls resistant to wind
Impact resistance depends on:
- wall geometry
- reinforcement
- type of mortar
- thickness of the glass block
3. Reinforcement and structural supports
The mechanical resistance of a glass block wall critically depends on reinforcement.
3.1 Horizontal reinforcement
Generally composed of:
- 2–4 stainless steel bars
- diameter 5–6 mm
- placed in every horizontal joint
3.2 Vertical reinforcement
Generally composed of:
- 2 vertical bars
- diameter 5–6 mm
- placed in vertical joints
3.3 Perimeter reinforcement
Essential for:
- wall rigidity
- absorption of expansion
- overall stability
4. Mortar and joints
Mortar is an essential structural element.
4.1 Structural mortar
Typical characteristics:
- compressive strength >10 MPa
- grain size 0–3 mm
- joint thickness: 10–15 mm
- controlled shrinkage
4.2 Expansion joints
They must be provided:
- along the perimeter
- every 3–4 meters of wall length
- every 3 meters of height
Expansion joints allow the wall to:
- absorb movements
- avoid cracking
- maintain long-term stability
5. Maximum wall dimensions
Recommended maximum dimensions for a glass block wall:
- maximum height: 3 meters
- width: unlimited (with expansion joints)
For walls higher than 3 meters:
- structural calculation is required
- expansion joints are mandatory
- increased reinforcement is recommended
6. Mechanical resistance of solid glass blocks (Full Glass Brick)
Solid glass blocks (100×200×50 mm) present:
- very high compressive strength
- greater weight
- absence of an air chamber
Typical values:
- ~337 N/mm² (single block)
- ~41–42 N/mm² (bonded block)
They are ideal for:
- decorative walls
- architectural elements
- high-traffic areas
- applications requiring high mechanical resistance
7. Fundamental warning: what has been tested and what has NOT been tested. Mechanical tests refer exclusively to the glass blocks.
The values reported derive from official tests performed on:
- single blocks
- bonded blocks
- wall samples under controlled conditions
No installation system has been certified.
During the tests, the following were used:
- specific types of mortar
- specific reinforcement
- specific geometries
- specific joints
But these materials and methods have NOT been certified. They were used only to perform the test, not to certify an installation system.
Real-world installation can completely change mechanical resistance.
If an installer uses:
- unsuitable mortar
- insufficient reinforcement
- joints that are too thin
- non-compliant materials
- non-approved geometries
The declared performance CANNOT be guaranteed.
8. Technical responsibility notice (mandatory)
The mechanical performance values reported derive exclusively from official tests performed on glass blocks.
Future Glass Block:
- does not certify installation systems
- does not guarantee the mechanical resistance of the finished work
- cannot be responsible for installation carried out by third parties
- cannot guarantee performance if materials different from those used in the tests are employed
Final verification of the work must be carried out by:
- structural engineer
- site management
- competent authority
The information provided is for informational purposes and does not constitute product certification.