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Rooflight Maintenance

How should you clean rooflights?

Zenon rooflights can be cleaned with a mild detergent or soap solution and a soft bristled brush.  Care must be taken to prevent any damage to the surface film protection. Separate details are available upon request. Pressure washing should not be used on metal cladding systems or rooflights used in metal cladding systems due to the risk of damage to surfaces and seals.

What happens if a rooflight gets damaged?

To preserve the non-fragility classification and service life guarantee, in most instances rooflights would require replacement. Small areas of damage that appear slightly cloudy or as a ‘bloom’ where the structure of the rooflight sheet has not been compromised, and the surface film is undamaged, do not generally require any remediation. Any more serious areas of damage where the rooflight appears to be white or crystalline in appearance, or where the surface film is damaged normally require replacement.

Suitable repair systems that might be available or offered on the market do no carry any guarantees of value and their application may cause further detriment to the product.

Rooflights should ideally be inspected on delivery and should not be installed wherever any damage exists. For further information, please refer to the Zenon document covering this subject.

How do I know if my roof is leaking or just condensation?

This is not always obvious, as cooling due to rainfall can cause condensation. If a rooflight is leaking, it will generally correlate regularly with certain weather conditions, even if not immediately obvious. Condensation is more likely to occur during colder weather and damper conditions irrespective of rainfall. The appearance of green algae in a rooflight assembly is more likely to indicate a leak from the outside.

How do I avoid condensation in large metal buildings?

There are several factors that can cause condensation, and low levels that occur at the coldest times of the year are sometimes unavoidable. Condensation can be due to the internal humidity levels, the use and activity of the building, a lack of ventilation, poorly insulated building elements, cold bridging in the construction or high temperature differences between inside and out.

The risk of condensation can be significantly reduced by using well insulated metal roof and cladding systems and by ensuring that the rooflights in these systems deliver the required thermal performance.  In situations where there is risk of condensation, rooflights that are better insulated than the minimum regulation requirements will reduce the risk and amount of condensation likely to occur. We offer a comprehensive range of rooflight thermal performance options. Click here to contact our technical team to discuss.

It’s too hot in my building, can I paint the rooflights to reduce the heat?

Painting or coatings may be applied, but the effectiveness of these solutions may be very short term with little or no guarantee and could result in insufficient daylight at other times of the year when it is required. The only effective way of reducing heat transfer through rooflights is by reducing the light passing through the rooflight.

Consideration should also be given to the internal heat gains and ventilation strategy of the building, and it should also be considered that lightweight clad buildings are at a greater risk of overheating from the sun irrespective of the presence of rooflights.

Any coating applied may not adhere adequately to the surface, or may require to surface of the rooflight to be damaged as part of the preparation process and therefore invalidate both the manufacturers service life guarantee and degrade the non-fragile performance.

Are your rooflights labelled so our maintenance engineers can see how old they are?

This kind of information should be contained in the building records or building maintenance manual. Our rooflights are printed along their edge with identification marks, relating to the manufacture and specification of the product.

This can only be applied to the outer surface of the sheet, and where it will remain visible after installation, will also be exposed to UV attack and weathering and therefore may become illegible long before the rooflight becomes unserviceable.


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Long March, Daventry, Northamptonshire, NN11 4NR, UK
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