Crazy pavings are categorized into small, medium, large, and extra-large.

Note that different suppliers may have varying criteria for these size terms. For example, what one supplier calls “small” may be “medium” for another. It’s best to check how many slabs are needed to cover 1 square meter for the stated size.

At Minera, for instance, medium-sized slabs of Light  Oppdal slate typically range from 2 to 5 slabs per square meter.

Aesthetic preference:

Small slabs create a more dynamic look with more joints, while larger slabs offer a calmer, more solid appearance, evoking the feeling of walking on bedrock.

Stability:

This is important when laying slabs on loose material. For slabs glued to a concrete base, stability is consistent across all sizes. Larger slabs are heavier and more stable on loose surfaces, while small slabs may be less sturdy.

Cost:

Small slate slabs have the lowest price per square meter, with prices increasing for larger slabs.

Ease of handling:

Small slabs are easier to handle manually compared to larger ones.

You can purchase crazy paving sorted by thickness range (e.g., 2 – 4 cm thick) or with a fixed thickness (e.g., 12 mm, where all slabs are cut to the same thickness).

Thickness range: Cheaper to buy but more time-consuming to lay, as you need to adjust the base (whether adhesive or sand/gravel) to account for height differences.

Fixed thickness: Faster to lay but slightly more expensive. A major advantage is not needing to adjust with adhesive or loose materials.

Consider the load the surface needs to bear and the installation method. All recommendations assume proper installation of the slate.

Installation Method

Slate glued to a concrete slab can generally be thinner than slate laid on soil or gravel:

• Glued to concrete: 10 mm to 30 mm
• Laid on soil/gravel: 20 mm to 80 mm

Load Capacity

• Pedestrian traffic only: 20 – 30 mm
• Light vehicles (e.g., cars in a driveway): Minimum 40 – 60 mm
• Heavy vehicles (e.g., tractors/trucks): 60 – 80 mm