Technical Specification

Polycarbonate (Solid Sheet)

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

Double Skin 2.6 W/m²K As installed
Triple Skin 1.8 W/m²K As installed
Quad Skin 1.4 W/m²K As installed

Light Transmissions
Clear 87%
  • a high light transmission
  • allows full vision of views & objects
  • minimum privacy
Diffused 84%
  • a high light transmission
  • increased privacy
  • reduced glare and shadows
Bronze 50%
  • 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.


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.


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.


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

L2 Trade Range Kerb

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


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 2 sides Rotary Vent 15.6cm² (1560mm²)

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

Vented 4 sides Rotary Vent 31.2cm² (3120mm²)


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.


The ‘red book’ ACR(M) defines a test for non-fragility which can be applied to any roof assemby 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 stired 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.


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


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.


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.


Direct 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.


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