Dalite Rooflights

Performance and Technical Compliance


Sustainability and the Environment

Icopal strive to reduce consumption of energy and raw materials, and recycle as much as possible. Icopal have attained the environmental standard ISO 14001.

Product Testing

Icopal is committed to produce quality products that meet the needs of our customers, which is recognised from our ISO 9001 standard. As well as complying with stringent quality procedures, the Icopal Dalite range of rooflights are tested to recognised industry standards. These tests will be specific to each product, but may include a selection of the following:


The Dalite range of rooflights are tested in accordance with ACR[M]001:2005, and achieve a Class B non-fragility rating.
This demonstrates a safe and robust product tolerant to impact damage. A non-fragility rating is required by the HSE (Health and Safety Executive), in order to comply with CDM (Construction (Design and Management)) Regulations.

Fire Rating

Icopal Dalite rooflights are compliant with UK Building Regulations in relation to fire rating. Icopal use polycarbonate glazing in the Dalite range which achieves Class B, s1, d0, thus exceeding the newer European requirement in all aspects.


The Dalite range is designed to meet exacting standards for weather performance and comply with the requirements of BS EN 1873:2005.


The trickle (hit and miss) ventilation system used as an option in the Dalite range meet the requirements outlined in BS EN 13141 Part 1 2004 for air flow, air leakage and weathertightness.
Options for both background and purge ventilation can help to meet the requirements of Part F as set out in the UK Building Regulations.


Dalite rooflights are guaranteed fit for purpose in normal industrial conditions for a period of 20 years. They will not become perforated, or loose significant structural strength, or distort to the extent of losing weathertightness.
The polycarbonate carries a manufacturer’s warranty, which guarantees that for the first 10 years of the main guarantee period a cleaned sample of rooflight shall:

  • Not show an increase in yellowness index of more than 10 Delta compared with the original value when tested in accordance with the method described in ASTM D1925 (1977)
  • Not show a loss of light transmission of more than 10% when compared to its original value when tested in accordance with the method described in ASTM D1003 (1977).
  • Achieve an impact resistance of at least 27Nm when impact tested using a falling dart impact test.

Please ask Icopal Technical Department for full warranty details.


The Icopal Dalite range has full BBA approval. For further information, please contact Icopal’s Technical Department. 

Thermal Performance

The Dalite range can be specified to exceed the thermal performance required by Part L of the Building Regulations. Read more...

Design Considerations

Icopal can offer support and advice to ensure that the correct Dalite rooflight is specified for the right application. The following points should be considered, but please contact Icopal’s Technical Department for further assistance.

Building Regulations Approved Document L 2010 – Conservation of Fuel and Power

This approved document is designed to provide practical guidance on ways of complying with the energy efficiency requirements of the Building Regulations. These regulations are split in to 4 sections:

1. Approved Document L 1A - New dwellings
This document sets out a minimum energy performance requirement for new dwellings. It looks at CO2 emissions as a measure of energy performance against a standard. It sets a maximum U-Value of 2.0 W/m2K for a complete rooflight unit.

2. Approved Document L 1B - Existing dwellings
This section, which relates to existing dwellings, sets the maximum U-Value at 1.6 W/m2K for a complete rooflight unit. It recommends that the rooflights are draft-proofed units.

3. Approved Document L 2A – New buildings other than dwellings
This document sets out a minimum energy performance requirement for new dwellings. It looks at CO2 emissions as a measure of energy performance against a standard. It sets a maximum U-Value of 2.2 W/m2K for a complete rooflight unit.

4. Approved Document L 2B – Existing buildings other than dwellings
Part L2B sets a U-Value requirement of 1.8 W/m2K as defined in the vertical plane (which equates to 2.1 W/m2K in the horizontal plane).

Solar Gain

Solar heat gain within a building can occur when the sun heats the building up during the day. Solar gains are beneficial in winter as a means of offsetting heat demand, but can contribute to overheating in the summer months. To lessen this effect, solar controlled glazing can be used to reflect solar radiation. This in turn reduces the need for air conditioning to cool the building, thus reducing CO2 emissions. Approved documents L 1A and L 2A outline the requirements to limit solar gain.

Optimum rooflight Area

As outlined above, rooflights make a positive contribution to reducing CO2 emissions. Research has shown that typically the total CO2 emissions associated with all aspects of operating a building without rooflights can be over 50% higher than for a building with 12% rooflights. The optimum area of rooflights will vary for each building. However, research has shown that a rooflight area of 15-20% of the roof area, will contribute to an overall reduction in CO2 emissions in most buildings.

Fire Safety

This is covered by Building Regulations Approved Document B 2006. Volume 1 relates to dwelling houses and Volume 2 relates to buildings other than dwelling houses. The requirements are outlined as either “national classifications” (based on BS 476 standards) or “European classifications” (based on BS EN 13501 Part 1: 2002). Whilst the tests are different and therefore not exactly equivalent, products can meet either requirement.

Air Tightness

Air tightness relates to a buildings air leakage rate, when pressure tested. Therefore the building should meet the relevant value as measured against a standard. Guidance is given within the Building Regulations Approved Document L 2010 (Parts L1A, L2A and L2B).

Resistance to the Passage of Sound

This is outlined in Approved Document E of the Building Regulations (Resistance to the Passage of Sound). It sets guidance for resistance to sound transmission relating to buildings, also highlighting schools. Icopal provide an acoustic pack within the Dalite range where particular acoustic performance is required.


As outlined in Approved Document F1 of the Building Regulations (Means of Ventilation), there should be adequate means of ventilation for people within the building. Ventilation through rooflights provides a useful way of complying with the regulations, especially when other means of ventilation can be limited.


BS 6229: 1982, Code of Practice for flat roofs with continuously supported coverings, outlines that the waterproofing upstand detail should terminate at least 150mm above the uppermost roof surface to which the roof covering is bonded or dressed.


Condensation is created due to environmental conditions when warm moist air comes into contact with a cooler surface.
However as temperature and humidity levels within a room below a rooflight are beyond our control, then no guarantees can be given against the formation of condensation. Higher levels of insulation inherently built into the Dalite range of rooflights, and the cassette glazing system, minimises the risk of condensation.

Limitations on use

The Icopal Dalite range of rooflights are designed to be used on standard flat Icopal membrane roofs on a pitch no greater than 10°, and in situations where excessive wind loads, or extreme climatic conditions cannot arise. Please contact Icopal’s Technical Department for a copy of the Warranty and Terms and Conditions for further assistance.

Health and Safety

Under the Construction (Design & Management) Regulations – CDM, it is the responsibility of the employer to ensure that any employee required to work at height must be suitably protected from any potential fall hazards. In the event of a fall the equipment used must be of sufficient strength to arrest a worker’s fall.

The Work at Height Regulations 2005, state that there is a duty placed on employers, the self employed and anyone who controls the work of others at height to provide a safe method of work.
Therefore it is important that when installing or maintaining rooflights, there is adequate protection for the operative against falling. Icopal can supply advice and integrated roof safety systems which will assist in these processes. Please contact Icopal’s Technical Department for further information.

Technical Support

Icopal’s extensive National Sales and Specification team is available throughout the UK and Ireland to offer technical advice, specifications, site surveys and support for any enquiry you have. This is backed up by Icopal’s expert Technical Department, which is able to provide technical drawings and specific detailing assistance to complete a fully integrated service. 


    Contact Icopal 0161 8654444

    Find Local Support

    To discuss your project in more detail please contact
    Your Local Area Manager


    Technical Support


    0330 123 4585

    Email: technical.uk@bmigroup.com


    Sales Enquiries & Orders


    0843 224 7400


    0843 224 7401

    Email: sales.admin@bmigroup.com

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