Sub-construction

A hassle-free installation starts with the sub-construction.

The sub-construction raises the modules above the roof surface, protecting the structure against water and drifting snow. The sub-construction provides the supporting base for the modular skylights.
The skylight modules require an accurately dimensioned sub-construction, which can carry the module installation system.
The load-bearing capacity of the sub-construction needs to be calculated for each individual project based on the building design and application.
The sub-construction is not part of the prefabricated modular system, and the VELUX Group does not take responsibility for the sub-construction.

Wood

Wood remains the best choice for creating a light and economical sub-construction with maximum energy performance. Wood is not recommended for larger solutions and Ridgelight installations.

Steel

Steel offers flexibility in combination with great strength. Steel also permits maximum insulation.

Concrete

Concrete provides a strong, but heavy sub-construction, best suited for concrete buildings. Concrete sub-constructions are usually cast on site.

Securing modular skylights to the sub-construction

Using steel profile or flat steel

The top of the sub-construction should be finished with a steel profile or flat steel to provide a strong and level surface as the base of the installation brackets with clamps.

Flat steel on wood

Steel profile on steel

Flat steel on concrete

Wood profile on wood is not recommended by VELUX Commercial.