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Technical Specification


  • Polycarbonate (Solid Sheet)

UV protected polycarbonate offers high impact resistance as well as a variety of glazing options: clear; diffused and bronze.


  • U-Values

Double Skin2.6 W/m²KAs installed
Triple Skin1.8 W/m²KAs installed
Quad Skin1.4 W/m²KAs installed


  • Light Transmissions

  • a high light transmission
  • allows full vision of views & objects
  • minimum privacy
  • a high light transmission
  • increased privacy
  • reduced glare and shadows
  • a low light transmission
  • reduced solar heat gain
  • cuts down the brightness of sunlight


  • Solar Gain

The solar gain (‘G’ value) can be improved to a more manageable level by introducing varying tint interlayers to the polycarbonate rooflight construction thus reducing the heat build up occurring from transmittance through the rooflight glazed area.


  • Acoustic

Typical airborne sound reduction for a Triple skin rooflight is 30-35dB.


  • Fire Rating

Products comply with current UK Building Regulations covered under BS 476 and European Standards under BS EN 13501.


  • Glass

As an alternative to polycarbonate, safety glass is very popular in the commercial and retail environment, Toughened glass is manufactured using a heat tempering process, which in turn produces a very versatile material in contemporary architecture. Laminated glass provides benefits such as sound reduction, added security and additional safety. Various glass options are available on request. Our most common options are available online: glass rooflights


  • Fixings

Security fixings with seala caps and washers are supplied with all polycarbonate rooflights. Direct do not supply fixings to secure to a builders upstand/roof deck.


  • UPVC Kerbs (DR168)

U-value 2.05 W/m²K *

168mm high kerb with 100mm splay and 60mm fixing flange to allow fixing to flat or inclined roof structures, with a profiled outer face to improve membrane adhesion.

Hot Box Tested by the BBA
** Calculated by the BRE as average weighted U-value


  • Ventilation

Building Regulations Part F requires background ventilation not less than 8000mm² of controllable and secure ventilation. If rapid ventilation is necessary then this should equate to 5% of the total floor area of the room. On a standard kerb 1200 x 1200 the free air space is:

Vented 2 sides Hit and Miss Vent: 55.5cm² (5550mm²)

Vented 4 sides Hit and Miss Vent: 111cm² (11100mm²)


  • Maintenance

Rooflights can be cleaned if needed by using mild detergent and warm water, using a soft cloth or sponge. Do not use an abrasive cloth or strong detergents. It is advised when cleaning any rooflight that you should always assume that they may be fragile and you should never walk, stand or lay across them. Additional H&S equipment may be required. Further info on maintenance topics can be found here.


  • Non-Fragility

The ‘red book’ ACR(M) defines a test for non-fragility which can be applied to any roof assembly to indicate whether the roof can support the loads imposed by a person falling or stumbling upon it.  Direct have had their rooflights independently tested by the BRE to ensure they meet at very least a class ‘B’ rating.


  • Handling and Storage

Rooflights must be stored and handled with care. Even with the protective wrapping still in place, rooflights should never be stacked on top of each other, but always in a dry place away from direct sunlight, on their edges with a separator between.


  • Design

Full technical drawing facilities are available from Direct. Any queries regarding our systems should be addressed to our technical staff.


  • Specification

Direct have a continuous research and development programme and reserve the right to improve or modify products without notice.


  • Building Regulations

Direct’s range of rooflights and kerbs optimise performance to ensure Part L of the Building Regulations can be met with confidence, together with the requirements of the Construction Products Regulation 2011 (CPR) meeting not only the British Regulations but also adhere to European Standards.


  • CE

Rooflights and kerbs are manufactured in accordance with the harmonised standard BS EN 1873:2005 under the (CPR). All rooflights and kerbs manufactured and distributed from Direct’s premises covered under the regulatory standard will carry the CE mark giving greater confidence that the product being supplied is of the best possible quality and most importantly compliant to current legislation.


  • BBA

Direct Rooflights hold a BBA certificate for products sold into the marketplace and are proud in the knowledge that the products supplied meet the required quality standard to achieve such status giving our customers further confidence that the products are of the highest quality.


  • Condensation

The formation of condensation on the inner skin or between each glazing skin of a rooflight is dependent on numerous environmental factors such as humidity, internal and external ambient temperature and/or natural/mechanical air movement. Condensation will occur where a surface at a lower temperature than the surrounding air interfaces with high humidity conditions.

Condensation will therefore worsen during the winter months where temperatures drop and air humidity through rainfall substantially increases.

If the humidity in the air at source (i.e. inside the building) cannot be reduced or removed by addressing the moisture producing events, then the risk of condensation forming on or in the unit will increase substantially.

The formation of condensation may therefore form with there being no design fault whatsoever in the rooflight and/or the moisture developing activity decreases.

The Seller does not give any guarantee on the non-occurrence of condensation on any of its products.