Impermeability - NP EN 539-1

The impermeability of individual roof tiles and accessories is an essential functional demand and a contributing factor to the proper performance of the roof they are a part of. The impermeability of clay roof tiles and accessories must be classified as either grade 1 or grade 2; only the former may be used on roofs with no interior watertight coating.

The maker must declare the test method used (1 or 2) from those described in the norm, so as to evaluate conformity with this requisite.

Flexural strength - NP EN 538

Roof tiles must be able a certain load in flexure without breaking.
The values defined for each tile type are as follow

Torreense Roof TilesFlexural strength - NP EN 538
Marselha900 N
Canudo1.000 N
Lusa1.200 N
Milénio1.200 N

Frost resistance - NP EN 539-2 

Under certain atmospheric conditions roof tiles will be subjected to constant wear due to the frosting and defrosting of absorbed rainwater, especially when sudden temperature variations occur within a short time span. 

Thus, materials must comply with specific requisites when applied in areas prone to this sort of occurrence. The test method to evaluate roof tile conformity varies according to the country where they will be used.
In Portugal the C method is used; roof tiles must resist to 50 frost/defrost cycles with no defects.

Fire resistance

Requisites relating to fire evaluate two main aspects: resistance to external fire sources and their reaction to fire. 

Clay products comply with the requisites relating to resistance to external fire sources, as they are in accordance with the definitions provided by Commission Directive 2000/553/EC.

As for reaction to fire, products comply with Class A1 requisites and do not require testing, in accordance with Commission Directive 96/603/EC.