Frequently Asked Questions

Common questions from our customers. If you can’t find the answer you’re looking for, get in touch with us.

1. What sizes are the roof lanterns available in?

We can manufacture to any plan size but standard sizes are more economic.

2. Who will install the roof lantern?

As far as the preparation work is concerned below the roof lantern (whether it be an existing roof or a new roof) this can be done by any competent builder. It will be necessary to create the required aperture (strengthened if needed), create an upstand/kerb for the roof lantern to sit on, lining out the aperture as appropriate and making sure that the roof surface material is carried up the outside of the upstand/kerb correctly.

As far as the actual installation of the lantern is concerned there is no reason why this cannot be done by a competent carpenter or practical individual. The lanterns come with full fitting instructions and we are happy to help if needed.

3. White powder coated aluminium glazing cappings or painted timber?

For the majority of applications we recommend the white aluminium glazing cappings which have a neat moulded section and are maintenance free. We supply these as standard unless requested otherwise. However, should you prefer a slightly more traditional glazing capping then painted timber cappings are available at no extra cost. Just let us know.

4. What size roof lantern should I have?

This is a rather subjective question depending on usage of the area below, personal preference, amount of light required, etc. It is surprising the amount of light even a 1000mm x 1000mm roof lantern will let in. From our own experience we have found that a roof lantern 1200mm x 1800mm in size gives an excellent area of light and the feeling of space for a medium sized room.

Remember that the upstand/kerb on which the roof lantern sits needs to leave adequate clearance all round for general maintenance purposes of the roof. Ideally 300mm minimum clearance is required although you might get away with a bit less.

5. What dimensions should the roof lantern supporting upstand/kerb be? Where are the roof lantern measurements taken from?

The measurements for the roof lantern are taken at the external face of the supporting timber upstand/kerb. This allows us to construct the lantern cill with the correct overhang for weathering purposes. The actual thickness (in plan) of the support timber upstand/kerb only need to be 50mm plus whatever felt, asphalt etc is needed for the outside and perhaps plasterboard with a finish on the inside. This is perfectly adequate for a small to medium sized lantern; for larger roof lanterns 100mm thick (or larger, depending on insulation etc) upstand is more suitable.

Ideally the top of the upstand/kerb (bottom of the roof lantern cill) is a minimum of 150mm above the finished roof surface.

6. What about ventilation?

It is well worthwhile considering whether ventilation is required, especially if the space below is south facing and receives a lot of direct sunlight, whether it has opening windows, or if the space is a kitchen where lots of heat and steam will be generated.

There are three options for ventilation:

  • Trickle vents – These are available in powder coated aluminium and allow a small amount of air movement.
  • Top hung opening sashes – These are available if the roof lantern has side lights. They can be opened either manually (with a pole) or by electric motor and switch with or without various automatic control options.
  • Opening skylights – If the roof does not have side lights it is possible to ventilate using powder coated aluminium top hung skylights. Aesthetically, skylights do break up the purity of line to some extent. This is more noticeable on small roof lanterns since the frame of the skylight does take some of the light. Having said that the particular design we use works very well and is fully storm proof. Either manual or electric operation is available.
7. How do I care and maintain the roof lantern? How often do I have to paint it?

The roof lanterns made by Traditional Roof Lanterns are made from the very best materials and will last for many years, but an annual check up will ensure the best possible longevity.

Once a year it is advisable to check the exterior (where it is accessible) of the roof lantern and take appropriate action as follows:

Clean lantern and glass with a mild detergent (or glass cleaner in the case of the glass). Inspect external paintwork. Normally this will last for many years without attention; however occasionally there is a need to touch up the paint perhaps where there are mitres as on the corners of the cill in the case of a roof lantern with sidelights.

In this instance then the procedure would be to rub down the area in question. Apply ‘painters mate’ or a similar acrylic mastic if there is a small gap to be sealed.

Touch up the area with at least two coats of water based microporous paint which we can provide if necessary.

For powder coated aluminium glazing and cappings and opening skylights, cleaning down with a mild detergent should be all that is necessary.

8. Does the roof lantern come with a guarantee?

Below are the main exerts from our Guarantee and Maintenance Manual.

To read / download a full PDF copy please click HERE 

Materials and Structural Integrity

All materials used in the construction of our roof lanterns are guaranteed for a period of:

  • 10 years for structural timber / glazing capping.
  • 5 years manufacturers guarantee for standard double glazed units.
  • 2 years manufacturers guarantee for electric motors and controller units.

(please see appendix A for glazing guarantee period and below for Electric Motors and Control Units). The structural integrity of each roof lantern is also guaranteed against failure assuming that no other external influences cause an adverse effect.


If others install the lantern, our guarantee only covers the materials used, including the glass. Any leaks that may occur would be down to the installer.

Glass Units

As stated in appendix A, the double glazed units themselves are guaranteed for a period of 5 years. This does not automatically cover the labour cost for replacement although in practice we will sometimes accommodate this cost depending on the individual circumstances.


The lantern finish is factory sprayed, with industry standard micro porous paint designed for external joinery (Teknos AQUATOP 2600-24 a highly versatile, robust and easy to use topcoat, which typically is used for exterior windows, doors, shutters, conservatories or claddings).

We apply 2 coats of primer and 3 coats of topcoat, applied with an airless spraying system to guarantee a minimum of 200 microns of paint per wet pass.

The paintwork should stand up very well and give many years of service, but it would pay to inspect the exterior of the lantern at least once a year.

We recommend the following to maintain and extend the life of your exterior:

  • Once cleaned, scrape, lightly sand and touch up any necessary areas with a matching microporous paint or stain. Any bare wood should be primed first.
  • Weather seals to opening skylights / sashes should be checked and cleaned.
  • Any vents should be cleaned, and any blockages removed.
  • Timber is a natural product and therefore performs differently through the year.

Generally, the only likely maintenance aspect in this respect is that should a corner joint in the lantern cill open up slightly it would be advisable to fill the joint with ‘Painter’s mate’ or a similar proprietary flexible filler and touch up with white paint afterwards. A small amount of movement in the lantern structure is quite normal for any timber product and does not impair the structural integrity.
Always follow the instructions given by the paint manufacturer.


Hardwood in many cases is now ‘engineered’, which means that it comprises several layers of timber bonded together. This increases stability and strength but a by-product is that on rare occasions a small hairline crack may appear due to fractional movement. This is not structural and will not impair the integrity of the lantern. A small touch up with painters mate / paint will remedy the situation.

Lead Ridge Capping:

Lead ridge cappings work extremely well and will last for an exceptionally long time.

HOWEVER, although patinated on both sides before delivery to site they must be re-patinated externally once the lead capping has been finally dressed down by whoever is installing the lantern. This is to prevent oxidization of the lead which can look a bit unsightly and run down onto the glass units. Eventually the capping will simply weather down, but it is recommended that the lead ridge capping is re-patinated every year.

Lead cladding to rafters will also need re-patinating if it is used with self-cleaning glass and / or it is required that the lead stays its original colour.

Self Cleaning Glass (Bio-Clean):

Self-cleaning glass works well. However – 2 important points:

  • Self-cleaning glass is not ideal with a lead ridge capping. The integrity of the lantern is not impaired but, in some instances, lead oxide from the capping has been known to cause some streaks on the external glass units. To minimize the risk of this we recommend frequent patination of the lead. See appendix A under self clean glass.
  • There are specific cleaning agents that we recommend for self-cleaning glass which do not harm it. Please see Appendix B.

Electric motors and control units

These have a manufacturer’s guarantee of two years. If a replacement unit is needed, we will supply one under guarantee, but the electric installation work / interface is not our responsibility. If the unit fails, we purely supply a new unit by post. The faulty unit would need to be returned for inspection first.

Still have questions?

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