Five design considerations when specifying modular skylights

Modular skylights are integral to the fabric of a commercial building, and often make up a significant proportion of the roof area. They must meet multiple performance criteria, while also allowing natural light into the building.

In order to specify skylights capable of achieving the standard of performance required, this blog post gives an overview of five design criteria to keep in mind when comparing products and talking to manufacturers.

1. Thermal performance and ventilation

These two criteria could easily be considered separately. For the purposes of skylight specification we are classing them together in terms of ‘thermal control’, or making sure that internal temperatures are neither too hot nor too cold.

The amount and type of roof glazing needs to achieve a balance between the thermal efficiency and air permeability of the skylights, while pre-mounted blinds can help to control solar gains into the building. Ventilation is critical to providing a healthy indoor climate, but also increases heat loss and must therefore be controllable.

Modular skylights contribute to whole building calculation methodologies used to assess Building Regulation compliance. Speaking to a skylight manufacturer at an early stage helps to avoid under- or over-specification, which can otherwise lead to compensatory measures elsewhere in the building.

2. Contribution to daylight design

Roof glazing offers greater access to unobstructed sky and sunlight, and brings daylight deeper into a building. Skylights therefore have a significant role to play in achieving the performance levels set out in EN 17037 ‘Daylighting in buildings’.

Establishing the glazing specification and undertaking climate-based daylight modelling in the early stages of a project improves certainty for the project team, and makes it more likely that the finished building will deliver what is promised in terms of both building performance and occupant comfort.

3. Load-bearing

Modular skylights need to be able to resist wind loads and bear the weight of imposed loads such as snow. Loads are also imposed by people accessing the roof for repair or maintenance, and impact testing results declared by manufacturers demonstrate the safety of units.

4. Acoustics

Double or triple glazing does not apply to thermal performance alone. The thickness of glass panes in a skylight module, and the width of the air spaces between them, all forms part of a unit’s contribution to acoustic comfort. Skylight specification should take into account the building’s location, and the needs of the occupants.

Where a building is situated in an urban environment or near a busy road, acoustic performance becomes particularly critical. In some building types, like schools and hospitals, poor acoustic comfort can actually be detrimental to the wellbeing of the people inside.

5. Control

When it comes to the actual operation of the skylights, is manual or automatic control required for the project? There are times when occupants need control over their own comfort and internal environment. Automatic operation, however, allows skylights to react quickly to changing conditions, providing adaptive comfort for building users that manual control alone would struggle to achieve.

VELUX Modular Skylights offer two different types of control, VELUX INTEGRA® and an Open System solution.

VELUX INTEGRA® is a simple, wireless system for comfort ventilation and roller blind operation, with the option to specify a rain and wind sensor as part of the module too. ‘Open operation’ allows the skylights to be incorporated into a Building Management System, from which they can be operated based on temperature, humidity or carbon dioxide levels.

What makes modular skylights the preferred choice?

VELUX Modular Skylights are highly insulated glazed units, manufactured to tight tolerances and offering repeatable and dependable performance. They are CE-marked and arrive on site fully prefabricated, complete with customised flashings for complete watertightness.

The modules are designed to work as a single system from the moment they are made in the factory, and can be linked in rows to suit the building shape and roof design. Skylight modules and their flashings have a 10 year guarantee and a lifespan of 30 years.

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For further specification support, brochures and guides are available on the website, as are CAD and BIM object downloads. VELUX Commercial also offer a comprehensive, RIBA CPD-accredited learning programme, highlighting the importance of daylight in commercial buildings, and the benefits of modular products in creating better environments for learning, working and recovering.