Algal or fungal growth on façades is caused by moisture from rain or condensation on the rendered surface not evaporating quickly enough. The higher the humidity of the outside air and the lower the temperature of the rendered surface, the higher the condensation level. The humidity lasts for a particularly long time on the sides less exposed to the sun (north and west) and when trees or plants cast shade on the façade.
The growth of algae and fungi is favoured by the absence of protection against rainwater, such as eaves or a window sill, or against water splashes at substructure level.
Algae and fungi can form on both insulated and non-insulated façades. As a rule, thin-layer exterior renderings on insulated façades and coarse-textured façades are more vulnerable to algal growth. On the other hand, mineral coatings covered with a suitable paint are less vulnerable.
Green pollution of rendered façades is pollution caused by algal growth or fungal attack. This pollution is an undesirable and yet natural phenomenon linked to the ageing of a façade, which occurs when certain conditions favourable to the proliferation of algae are met. In essence, it is an aesthetic problem and has no negative impact on the building itself or the health of the occupants.
Klima-Agence has developed a short and simple standard user manual that contains a description of the main elements of the different technical installations and their parameters, as well as information about maintenance schedules. You can download the different sections of the LENOZ user manual.
The data relating to the dismantling capacity applies to all construction elements of the building envelope as well as to the internal structure (walls, ceilings):
· external wall
· floor slabs
· intermediate slabs
· internal partitions.
The greater part of a construction element, i.e. more than 50% of its surface area, must be easily removable or separable.
The following are exempt from this dismantling condition:
- the coating layer;
- buried elements.
For the dismantling capacity, all layers of the construction element used for calculation of the U-value must be taken into consideration, including seals and membranes. All buried elements are excluded; wall, floor and ceiling coverings (e.g. wallpaper, paint and flooring, etc.) are not taken into account. A list of materials should be drawn up, corresponding to the majority of buildings present . This list must cover the location, construction and nature of the assembly of materials. A model can be found in the LENOZ File template.
Calculation of the environmental indicators is directly linked to calculation of the thermal transmittance U and its inherent calculation rules. However, the layers of membranes and seals, which are negligible when calculating the thermal transmission coefficient given their low impact in terms of their insulation capacity, should be taken into consideration for calculation of the predicted environmental indicators.
For a new building, the construction elements of the thermal envelope (= external structure) as well as internal walls and slabs are taken into account.
For the elements of the external structure, all the layers taken into consideration for calculation of the U value are also taken into consideration for calculation of the I env and Iprim indicators.
Party walls and partition walls between different units in a block of flats should be considered internal walls (within the building envelope).
For existing buildings, only new insulating materials used during the retrofitting works are taken into consideration.
For existing buildings, only the primary energy requirement of the technical installations for conditioning the building should be considered for the Iprim indicator (Chapter 4.2). The primary energy expenditure of the existing building is not taken into account.
In the case of a LENOZ certificate for a new building, the Iprime indicator is calculated based on the primary energy requirement for the construction of the residential building and the primary energy requirement for the heating of the building over a period of 30 years.