Clay floor tiles, window sills and steps: how to choose

What are clay floor tiles, window sills and steps?

They are fired-clay pieces that solve very specific details on a building site: the rasilla (thin clay tile) is used for roof boards, falls and paving; the window sill protects sills and wall tops; and the clay step lets you build masonry stairs without laying brick after brick. They are light, traditional pieces sold by the pack or the pallet. In this guide we look at how to choose each one using the real data from Vetonek's range of clay tiles, window sills and steps.

Thin hollow brick or paving tile: which do I need?

Both are called "rasilla" in Spanish, but they are not used in the same way. The difference lies in the thickness and the intended use.

Thin hollow brick: stair risers, falls and boards

The Beasain thin hollow clay brick measures 24.5 x 10.8 x 2.7 cm (±10 %) and weighs 0.85 kg per piece. It is the thin, light piece for stair risers, forming falls on roofs, boards, thin tile vaults and thin-section closures such as cavities, ducts or boxing-in. It covers about 33 pieces per m², and the pallet of 960 pieces covers around 29 m² (≈816 kg). If your project includes a roof board, also see our guide to ceramic boards for roofs and ceilings.

Paving tile: terraces and walkable roofs

The Tolosa clay floor tile is an extruded piece of 13.7 x 28 x 1.3 cm in a reddish colour, for paving terraces, walkable roofs and screeds, or to get a rustic finish. It weighs about 0.8 kg per piece and covers about 25 pieces per m². It comes in three versions:

• Smooth, 1st grade: the standard smooth-surface version.
• Smooth, 2nd grade: accepts small cosmetic imperfections at a lower cost, useful if the finish is going to be rustic.
• Ribbed: a grooved surface, for outdoor areas where you want more grip.

All three are sold in a pack of 620 pieces (24.8 m², about 496 kg) or on a pallet of 1,240 pieces (49.6 m², about 992 kg).

Clay window sill: sills and wall tops that keep water away

The Azpeitia clay window sill protects window sills, wall tops and parapets on terraces and roofs, stopping water from running down the facade and staining it. It has the look of fired clay, in red, and suits both new build and facade refurbishment. It comes in two formats:

• Rectangular, 28 x 14 x 1.2 cm: laid on its long side (28 x 14) or its short side (14 x 28).
• Square, 20 x 20 x 1.4 cm: designed for wall tops and parapets.

It weighs about 1.4 kg per piece and is sold in a pack of 50 pieces (about 70 kg) or on a pallet of 710 pieces (about 994 kg), in either format. To lay it, spread the mortar with a fall towards the outside and let the piece overhang the wall face slightly so that the water drips well away from the facade.

Clay step: masonry stairs built faster

The Elgoibar clay step is a step of 25 x 16 x 28 cm and about 6.1 kg that is bedded on the slab with mortar. It replaces the traditional brick step-building: a single piece forms the step, you save mortar and pieces, and all of them have the same size, which helps to get an even staircase. It is ready to be finished with tile, stone, wood or microcement, and works for indoor stairs as well as terrace or garden stairs. It is sold in a pack of 60 pieces (366 kg) or on a pallet of 120 pieces (732 kg).

Before ordering, set out the staircase with the total height, number of steps, and the tread and riser specified in the project. If the staircase is part of a structural element, consult the technician or architect responsible for the works.

How much material do I need? Worked examples

• 20 m² terrace with Tolosa tiles: 20 × 25 = 500 pieces. A pack of 620 pieces (24.8 m²) covers it with a margin for cuts and finishing.
• 25 m² board with Beasain thin hollow bricks: 25 × 33 = 825 pieces. A pallet of 960 pieces (≈29 m²) leaves you a margin for cuts.
• Sills and wall tops with Azpeitia window sills: measure the linear metres. With the 28 cm piece laid on its long side you get about 3.6 pieces per metre, and on its short side about 7.1, not counting the joint.

Remember that pallets weigh up to 1,000 kg and are delivered by truck, so plan where and how they will be unloaded.

Laying tips

• Always prepare a firm, clean base with the fall needed to drain water on terraces and roofs.
• Spread the mortar in small areas so that it stays workable, and keep a regular joint.
• Check the fall and flatness with a straightedge and level as you go.
• Grout once the mortar has set and clean off the residue before it hardens.
• On steps, let the mortar set before applying the final finish.

If your project also includes walls or partitions, take a look at our guide to clay bricks: types and how to choose.

Frequently asked questions

What is the difference between a thin hollow brick and a paving tile?

The thin hollow brick is a thin, light piece for stair risers, falls, boards and thin tile vaults, while the paving tile is used to pave terraces and walkable roofs. In the range, the Beasain measures 24.5 x 10.8 x 2.7 cm and the Tolosa 13.7 x 28 x 1.3 cm.

How many clay floor tiles do I need per square metre?

It depends on the format: the Tolosa tile covers about 25 pieces per m² and the Beasain thin hollow brick about 33 pieces per m². Add a margin for cuts and finishing when calculating your order.

Which clay tile is best for an outdoor terrace?

For an outdoor terrace, the Tolosa tile is the piece designed for paving, and its Ribbed version offers more grip thanks to the grooved surface. The Smooth 2nd grade is a cheaper alternative if you accept small cosmetic imperfections.

How do you lay a clay window sill?

It is laid on mortar with a fall towards the outside and a slight overhang over the wall face, so that the water drips away from the facade. Then the pieces are aligned with a string line or straightedge, regular joints are left and the sill is grouted, cleaning off any excess mortar.

What is a clay step used for?

It is used to form the steps of a masonry staircase faster, with less mortar and fewer pieces than traditional brick step-building. It is bedded on the slab with mortar and is ready to be finished with tile, stone, wood or microcement.

Find all the pieces in the clay tiles, window sills and steps collection and discover the rest of the range in building ceramics.