The roof structure must follow a specific project that takes in consideration the materials used and the type of structure planned. 

The most commonly used structures are made of wood, concrete, stone and some mixed solutions resorting to metal profiles. The picture below shows examples of structures with and without insulation.

suporte-estrutura-madeira Wood structure

suporte-estrutura-alvenaria-betao Stone and concrete structure

suporte-estrutura-alvenaria-betao-perfis-metalicos Stone, concrete and metal profiles structures

The materials used in the structure are irrelevant to the proper performance of roof tiles. The constituting elements must fulfil their function. The roof tiles will be supported by those elements and fulfil their role.

Lath work

Laths are the simplest element of a roof structure. Roof tiles are laid on laths. Laths can be made of pine, concrete, pre-strained beams, metal profiles, PVC or mortar on stone slabs.

Lath spacing is the distance between the upper part of a lath and the lower part of the next lath.

While the roof tile maker should indicate lath values, these are merely suggested, as the actual spacing should be calculated at the construction site in accordance to the tile type, as referred in the section of this manual concerning the laying of each tile type (Lusa, Marselha, Milénio and Canudo).

Executing the lath work

Once lath spacing is calculated, the execution of the lath work must take the following aspects in consideration:

Dimension and shape of the lath

If using a prefabricated lath made of wood, PVC or other, it willl usually come in a rectangular shape with approximately 4x2cm and can be fixated by using screws or galvanized nails; if using metal profiles, fixation can be conducted by welding with na anti-corrosion treatment; for pré-strained beams, fixation is done by using mortar.

If the lath is done in situ (with mortar) it should have the following shape and dimensions:

execucao-ripado-1 Legend
1 - Base: 10cm
2 - Height: 3cm

Laths applied on a slab or directly on the insulating element should be spaced to allow ventilation of the lower side of the tile, to avoid the appearance of air chambers between rows. For more details and instructions regarding ventilation of roof tiles, please consult the section of this manual concerning the laying of roof tiles (Lusa, Marselha, Milénio and Canudo).

Applying the first lath

If the roof does not have eaves but includes a gutter, the following scheme should be followed:

execucao-ripado-2 Legend:
1. 1st lath
2. 2nd lath
3. 3rd lath
4. Lath spacing

When the roof includes eaves, the procedures described in the section of the manual concerning the laying of tiles (Lusa, Marselha, Milénio and Canudo) should be followed, specifically those referring to the application of accessories.

Considerations when planning the roof

One of the most frequent situations faced on building sites is the need to cut pieces to finish the roof. Cutting pieces should be avoided, both for aesthetical and technical reasons (cutting pieces may negatively affect roof performance).

Thus, it is convenient that the roof plan reduce the need to cut pieces to a minimum. The following picture shows an example of a roof where the architectural project took into consideration the adequate use of whole pieces.

recorte-cobertura Legend:
1 - 8 whole pieces
2 - 3 whole pieces