Clay floor blocks, lintels and shutter boxes: a guide

What each unit solves

Three clay units solve a good part of a floor and of the openings in a brick wall. The floor block (infill block) fills the space between the joists of the floor. The lintel spans the opening of a door or a window. And the shutter box houses the roller shutter drum and acts as a lintel at the same time. At Vetonek each one has its own name: the Legazpi clay floor block, the Ordizia reinforced clay lintel and the Deba clay shutter box. All are red, and their clay face takes the same finish as the rest of the works.

Legazpi clay floor block for one-way floors

The Legazpi floor block is the infill unit for one-way joist-and-block floors. According to the data sheet, it lightens the floor, insulates better than the concrete block and gives good grip for the plaster on the ceiling. It is used in storey floors, roof slabs and ground-floor ventilated floors, and in extensions and renovations with a new floor.

All the units are 25 cm long. What changes is the joist spacing (the distance between joist axes that the unit spans) and the depth:

• 60 cm joist spacing: depth 17 cm (9 kg), 22 cm (11 kg) and 25 cm (12.5 kg).
• 70 cm joist spacing: depth 17 cm (11.33 kg), 22 cm (13.6 kg) and 25 cm (16.3 kg).

Joist spacing and depth are chosen according to the floor calculation, so the decision belongs to the project and the technician in charge, not to the catalogue. Once defined, these are the sales formats:

• 60 x 17 x 25 cm: pack of 35 units (315 kg) or pallet of 70 units (630 kg).
• 60 x 22 x 25 cm: pack of 30 units (330 kg) or pallet of 60 units (660 kg).
• 60 x 25 x 25 cm: pack of 25 units (312.5 kg) or pallet of 50 units (625 kg).
• 70 x 17 x 25 cm: pack of 30 units (339.9 kg) or pallet of 60 units (679.8 kg).
• 70 x 22 x 25 cm: pack of 25 units (340 kg) or pallet of 50 units (680 kg).
• 70 x 25 x 25 cm: pack of 20 units (326 kg) or pallet of 40 units (652 kg).

The basic laying steps given in the data sheet are these:

1. Place and prop the joists according to the project, with the spacing of the chosen floor block.
2. Rest the floor blocks on the joists, well fitted and butted against each other.
3. Close the ends and gaps and fit the distribution reinforcement and the top bars indicated.
4. Dampen the units and pour the concrete for the compression layer.
5. Respect the curing and prop-removal times set by the site management.

Ordizia reinforced clay lintel for doors and windows

The Ordizia lintel is a brick joist with concrete and reinforcement, 6 cm deep. It arrives reinforced, so it is placed without formwork and the masonry continues above it; its clay face also grips render and plaster just as brick does. It comes in three widths (10, 14 and 20 cm) and nine lengths, from 100 to 300 cm in 25 cm steps: 27 sizes in all.

• 10 cm width: from 14.9 kg (100 cm) to 45.8 kg (300 cm).
• 14 cm width: from 19.86 kg (100 cm) to 62.5 kg (300 cm).
• 20 cm width: from 30 kg (100 cm) to 90 kg (300 cm).

To choose, the data sheet gives two pointers: pick the width equal or closest to the thickness of the wall, and a length that extends past the opening enough to bear on both sides, according to the project. For wide openings or load-bearing walls, check the data sheet, available on request, and confirm the size with the site management. It is sold singly in all 27 sizes or by the pallet.

Deba clay shutter box

The Deba box is a clay shutter box with concrete reinforcement, with a 19 x 35 cm section. It is placed over the window opening and solves both the lintel and the housing for the shutter drum, so the shutter is built into the masonry and finished like the rest of the wall. There are nine lengths, from 100 to 300 cm in 25 cm steps, with weights from 30.5 kg (100 cm) to 84 kg (300 cm).

In the longer lengths it is best placed by two people or with lifting aids, checking level and plumb, and bedding the ends in mortar before carrying on with brick above. Before closing the order, confirm the drum diameter and the type of shutter. It is sold singly or by the pallet: 18 units from 100 to 200 cm, 15 units at 225 cm, 14 at 250 cm, 12 at 275 cm and 11 at 300 cm.

How to choose according to the job

• New joist-and-block floor: Legazpi floor block, with the joist spacing and depth from the calculation.
• Door or window opening in a partition or brick wall: Ordizia lintel, matched to the thickness of the wall.
• Window or balcony door with a roller shutter in new build: Deba box.
• Renovations opening up or enlarging openings: Ordizia lintel or Deba box, depending on whether there is a shutter.

Masonry units and related guides

These units bear on masonry walls. For the wall you can look at the Oñati thermal clay block, designed for single-leaf walls, or the Gernika perforated brick, for load-bearing and party walls. If you are unsure which brick to use, read the guide to clay bricks and the guide to the thermal clay block. And if you are covering a roof or a ceiling with clay units, there is the guide to ceramic boards for roofs and ceilings.

Frequently asked questions

What is a clay floor block used for?

A clay floor block is the infill unit that fills the space between the joists of a one-way floor. The Legazpi floor block lightens the floor, insulates better than the concrete one and gives good grip for the ceiling plaster.

What is the difference between a floor block with 60 and 70 joist spacing?

The difference is the distance between joist axes that each unit spans: 60 or 70 cm. With 70 cm spacing the unit is heavier (from 11.33 to 16.3 kg versus 9 to 12.5 kg with 60 cm spacing), and the choice depends on the floor calculation.

What width of clay lintel do I need?

Choose the width equal or closest to the thickness of the wall. The Ordizia lintel comes in widths of 10, 14 and 20 cm, with a depth of 6 cm.

What is a clay shutter box and what sizes does it come in?

It is a clay box with concrete reinforcement that acts as a lintel and as the housing for the shutter drum. The Deba box has a 19 x 35 cm section and lengths from 100 to 300 cm.

Can lintels and shutter boxes be rendered or plastered?

Yes, their clay face is finished like the rest of the masonry. The Ordizia lintel grips render and plaster just as brick does; the Deba box is rendered or plastered like the rest of the wall.

Find all the units in the Floor blocks, lintels and shutter boxes collection and in the main Building ceramics category.