Ceramic Roof Boards and Ceiling Boards: How to Choose

What is a ceramic board (bardo) and what is it used for?

A ceramic board, also called a bardo in Spanish, is a long, flat clay piece that rests on small partition walls, joists or beams to form the substrate of a roof or the ceiling of a room. Vetonek's building ceramics range has two families with different uses: the Getaria tongue-and-groove board, for roofs, and the Lekeitio exposed-face board, for exposed ceilings between beams.

Getaria tongue-and-groove board: a flat substrate for the roof

The Getaria tongue-and-groove ceramic board forms the substrate of pitched or flat roofs over small partition walls or joists. Its side joint aligns the pieces and leaves a flat surface ready to receive the tile. It is made of red ceramic.

• Width 30 cm, thickness 4 cm: bevelled cut in lengths of 60, 70, 75, 80, 90, 100 and 110 cm; straight cut in 50, 80, 90 and 100 cm.
• Width 25 cm, thickness 3.5 cm: lengths from 50 to 110 cm, straight cut.
• XL range (width 25 cm) for long spans: 120 and 130 cm at 4 cm thick; 140, 150 and 160 cm at 5 cm; 180 and 200 cm at 6 cm.
• Weights: 9.8 kg for the 110 x 30 x 4 cm piece; 3.3 kg for the 50 x 25 x 3.5 cm piece; about 16 kg for the 200 x 25 x 6 cm piece.

According to the data sheet, the bevelled cut on the end improves laying output by up to 35% compared with conventional sizes (manufacturer's figure for the 30 cm width), and the standard range in 30 and 25 cm widths is made with an AENOR quality certificate (N mark). It is used on pitched or flat tiled roofs, over small partition walls, in lightweight roof slabs and in roof refurbishment.

Lekeitio exposed-face board: an exposed ceiling with a rustic feel

The Lekeitio exposed-face ceramic board is a handcrafted piece in flamed straw colour, fired in a wood-burning kiln, for exposed ceilings between timber or steel beams. It stays visible with no plaster or paint and, according to the data sheet, its strength means it can also be used as a substrate for the slab or the roof.

• Flat: 60 x 23 x 3 cm (4.3 kg, 7.6 pcs/m²) and 70 x 23 x 3 cm (5.02 kg, 6.5 pcs/m²), for smooth ceilings.
• Curved, revoltón type: 60 x 23 x 12 cm (4.3 kg, 7.6 pcs/m²) and 70 x 23 x 15 cm (5 kg, 6.5 pcs/m²), for vaults between beams.

It is designed for rustic homes and for the refurbishment of village houses, farmhouses and country homes.

Which one to choose for your project

• Roof substrate under tiles: Getaria, in the length that matches the spacing between supports.
• Exposed ceiling between beams: Lekeitio, flat for a smooth ceiling or curved for a vault.
• Long spans: the Getaria XL range goes up to 200 cm long at 6 cm thick.

The choice of length and thickness depends on the spacing between supports and on the loads on the roof or ceiling. That decision must be confirmed by the project engineer or architect, who will also specify the mortar or compression layer required.

How many boards do you need?

Multiply the m² by the pieces per m² of the model. For Getaria they range from 6.66 pcs/m² (50 x 30 cm) to 3.03 (110 x 30 cm), from 8 (50 x 25 cm) to 3.64 (110 x 25 cm) and, in the XL range, from 3.33 (120 cm) to 2 (200 cm). Example: for 50 m² of roof with the 100 x 30 x 4 cm piece (3.33 pcs/m²) you need 50 x 3.33 = 167 pcs, which is exactly 2 pallets of 84 pcs (168 pcs, 50.46 m²). If the roof has many cuts, add one pack of 40 pcs.

For Lekeitio, 20 m² of ceiling with the 70 cm flat piece needs 20 x 6.5 = 130 pieces, and one pallet of 145 pcs (22.31 m²) covers it with room to spare. Each variant in the store shows the m² its pack or pallet covers.

Laying in brief

Getaria:

1. Check that the partition walls or joists are level and spaced to suit the length you have chosen.
2. Spread mortar over the supports and seat the ends of the board.
3. Fit the side tongue and groove of the next piece and align the ends.
4. Fill the joints with mortar and check flatness with a straightedge.
5. Lay the mortar or compression layer specified in the project before fitting the tile.

Lekeitio:

1. Set out the beams at a spacing suited to the board length (60 or 70 cm).
2. Mix pieces from several packs before laying to spread the tones, because with wood firing the colour varies from one firing to the next.
3. Rest the boards on the beams with the exposed face down and the joints aligned.
4. Lay on top the layer the project specifies, without staining the exposed face.
5. Clean off mortar residue before it hardens.

And on top, the tile

The tile goes on top of the roof board. If you have not chosen it yet, compare the Segura clay barrel tile, the Hernani mixed clay tile and the concrete roof tile in our guide to clay and concrete roof tiles. And if you are also building the floor slab, see the guide to clay floor blocks, lintels and shutter boxes.

Frequently asked questions

What is a ceramic bardo?

A ceramic bardo is a long, flat ceramic board that rests on small partition walls, joists or beams as the substrate of a roof or ceiling. At Vetonek it comes as the Getaria tongue-and-groove board for roofs and the Lekeitio exposed-face board for exposed ceilings.

What is the difference between a tongue-and-groove board and an exposed-face board?

The Getaria tongue-and-groove board interlocks at the sides and leaves a flat surface as a substrate for the tile, whereas the Lekeitio exposed-face board is designed to stay visible in ceilings between beams, with its flamed straw colour. The first is used on roofs and the second on rustic ceilings.

What length of ceramic board do I need?

It depends on the real spacing between supports. Getaria offers lengths from 50 to 110 cm in the standard range and from 120 to 200 cm in the XL range for long spans, and Lekeitio 60 and 70 cm. Measure the spacing before ordering and confirm the length and thickness with the project engineer.

How many ceramic boards do I need per m²?

It depends on the model: from 6.66 to 3.03 pcs/m² for the 30 cm wide Getaria, from 3.33 to 2 in the XL range, and 7.6 or 6.5 for Lekeitio depending on whether it is 60 or 70 cm long. Multiply the m² by that figure and add a margin for cuts.

Can a ceramic board be left exposed on the ceiling?

Yes, the Lekeitio exposed-face board is designed to stay visible, with no plaster or paint, in ceilings between timber or steel beams. Keep in mind that the tone varies from one firing to the next, so it is best to order all the material at once and mix pieces from several packs.

Find all the boards in the ceramic boards and bardos collection and the rest of the materials in building ceramics.