Mk 2 Advance

BBS Polycarbonate Rooflights are manufactured to the highest standards and have been specifically developed for the flat roofing market. We offer one of the widest ranges of rooflights in the UK, and can accommodate bespoke designs to suit any structure.

Trade UnventedOur rooflights are manufactured from solid polycarbonate sheets with proprietary UV protection on both sides offering excellent weathering properties and light transmission. Polycarbonate offers a long service life, high impact resistance as well as a variety of glazing options such as clear, diffused, opal and bronze.

Our rooflights are available in either Pyramid or Dome profiles and can be supplied in either a Single, Double, Triple or Quadruple skin construction. These can be either combined with UPVC, aluminium or galvanised steel kerbs. Circular dome rooflights are available as a stand-alone item or together with aluminium or GRP kerbs.

The introduction of additional skins to the manufacturing process helps to improve both thermal and acoustic insulation as well as reducing the possibility of condensation; ultimately providing designers, architects and contractors with a wider range of options.

The benefit of using rooflights go further than just reducing energy consumption; research has shown that increased levels of daylight can aid health, learning and also increase productivity.

Our polycarbonate rooflights are all manufactured using a thermoforming process which has close similarities with vacuum forming except that greater use is made of air pressure. Each skin of the rooflight is manufactured individually and then combined to make the required rooflight. Each adjacent pair of skins are separated by a 20mm air gap to achieve the best possible thermal efficiency.

All rooflights are manufactured in accordance with harmonised European Standard BS EN 1873:2005 and carry the CE mark. Our range has been tested for fragility by BRE and attains a class B non-fragile assembly classification.

Our polycarbonate rooflights can comply with L1 and L2 of the Building Regulations. All the materials used in the construction of our rooflights and kerbs can be fully recycled.

BBS Glass Rooflights are an alternative glazing to polycarbonate, they are manufactured and designed to the highest standards and can be incorporated into the full kerb range.

To follow the correct procedure for overhead glazing we ensure the use of a safety glass comprising of a toughened outer pane and laminated inner pane. The laminated inner prevents any shards of glass falling back into the building in the event of the glass being broken.

Glass specifications vary widely, from standard clear, self-cleaning or high performance solar controlled glazing, we can accommodate most if not all requirements. Exceptional U-values can be achieved by using glass rooflights and also offers greater flexibility in achieving a variety of acoustic and solar factors.

The MK2 Advance kerb offers a ribbed section to the upper section of the external wall to give improved adhesion to a variety of waterproofing systems, it is manufactured using a ‘state of the art’ CNC manufacturing process, which guarantees accuracy and consistency of each unit produced.

This kerb can be used with a Double, Triple or Quadruple skin polycarbonate rooflight. It can also be supplied with a factory fitted, argon filled double glazed glass rooflight to further improve U-values.

Designed to be installed at the finished roof level it is therefore the ideal choice for retro fitting to an existing flat roof. The range offers a variety of different options. You can choose from Unvented, Hit and Miss Ventilation, Wormgear opening for maximum ventilation and Access Hatch units should roof level access be required.

The MK2 Advance kerb is 168mm high. It splays in from the base section by 100mm per side. The 60mm base fixing flange allows fixing to flat or inclined roof structures. The U-value for this profile is 2.05 W/m²K.

Unvented  – Fixed rooflight and kerb with no ventilation, used for areas that require natural light only.

Hit and Miss Titon Vents  – Offer manually operated ventilation via a sliding mechanism mounted internally to the kerb. The vents are opened and closed as required by hand or by pole. The vents can be installed on 2 or 4 sides of the kerb. Ideally used for areas that do not require a high volume of ventilation.

Wormgear – A brass telescopic winding mechanism is mounted internally to a 40mm high UPVC lifting frame which is fitted with galvanised steel reinforcement bars. This mechanism allows the user to remain at ground level and operate the unit with a winding rod. Wormgear rooflights offer a higher level of ventilation and can be opened up to approximately 300mm.

Access Hatch –  An opening hatch that utilises 2no gas rams to assist opening, mounted internally to a 40mm high UPVC lifting frame which is fitted with galvanised steel reinforcement bars. The hatch will open to between 80-90 degrees to give ease of access to roof level. The Access Hatch is available with Brighton Catch, Hasp and Staple or key operated locking mechanism.

Chain Motor – Utilises an electrically operated chain motor that is mounted to a 40mm high UPVC lifting frame fitted with galvanised steel reinforcement bars. The motor is available in 24V or 230V options and has the capacity to either be wired to an open/close switch or to a control panel (please note the rooflight will be supplied as standard with the motor only, controls are available at an extra cost). Chain actuated rooflights offer a higher level of ventilation and can be opened to approximately 300mm.

Trade Range Wormgear Trade Range Access Hatch MK2 Adapter Kerb Photo
Wormgear Opening Access Hatch Adaptor Kerb


Polycarbonate (Solid Sheet) UV protected polycarbonate offers high impact resistance as well as a variety of glazing options; clear, diffused, bronze and opal.


Single Skin 5.4 W/m²K As Installed
Double Skin 2.6 W/m²K As installed
Triple Skin 1.8 W/m²K As Installed
Quad Skin 1.4 W/m²K As installed

(additional laylight options available on request for increased thermal values)

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
Opal 50%
  • a low light transmission
  • maximum privacy
  • reduced glare and shadows
  • prevents vision of views and objects
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 way of 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 covered under BS EN 13501.


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

MK2 Advance – 2.05 W/m2K U-value. 168mm high kerb with 100mm splay and 60mm fixing flange to allow fixing to flat or inclined roof structures, with profiled outer face to improve membrane adhesion.

** 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 1200mm 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 111.cm2 (11100mm2)
  • Vented 4 sides  Rotary Vent 31.2cm2 (3120mm2)


BBS polycarbonate 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-fragilty 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. BBS have had their rooflights 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 edge with a separator between.


Full technical drawing facilities are available from BBS.


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

Building Regulations             

BBS 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.


BBS 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 BBS Structural Glazing 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.


Mk2 Adv001