How To Fit a Roof Lantern


So you have either decided to go for a roof lantern or have already purchased a roof lantern and never build one before. Well below we have put a comprehensive guide together so you know how to fit a roof lantern.

Some instructions may vary depending on the manufacturer but this applies for the majority.

Preparation is key

Before unpacking tour roof lantern, you should review the supplied layout drawing. Majority of the time the dimensions shown on the plan will be for the external face of the supporting upstand.

Ensure that the dimensions are in line with the building. The Skypod roof lantern in particular ring beam allows a 10mm tolerance per face if the overall width and length of the upstand perimeter are oversized. This tends to be the same with most manufacturers.

Roof Lantern Dimensions

Now time to Install

Now you have everything and it aligns with the size of the roof you are about to fit, it is time to install your roof lantern.

1.Ensure the kerb is clean and free from debris, then run a silicone bead around the external edge as shown above.

2.Ensure correct amount of glazing bar fixing studs are slid into the ring beam before any fixing commences. Position the ring beam so an equal overhang is achieved around perimeter and fix using suitable 5-6mm fixings at 300-400mm centres (starting and ending 100mm away from internal corner of the ring beam).

3. Run a bead of silicone sealant along the mitred edge of the ring beam to seal the corner joint, when the next ring beam is offered up.

4. Fix the adjacent ring beam ensuring the joint is tight. Remove any excess sealant and secure corner using a steel corner cleat with 4-off 4.8×25 LG screws (supplied).

5. If access to the bar ends is limited, it is advisable to fit the glazing stops and end caps as shown (right) before fixing rafters to the ring beam. You can then proceed to loosely secure the side rafters to the ring beam using the threaded studs located down the ring beam.

6. Supporting the ridge, the rafter bars can be secured to the ridge using the threaded studs. Once opposing rafters have been secured the ridge should be self supporting.

7. Using 2 x CRS8624S single studs, secure each hip to the spider casting. The body of the stud should locate between the retaining ribs on the lower casting face to stop the stud from spinning.

8. Locate the hips onto the external ring beam studs and loosely secure using fixing nuts.

9. Fasten the central rafters to the spider using 1 x CRS8625S double stud and nuts. If jack rafters are present.

10. If not already fitted, clip in the eaves beam seals between the rafters and hips using a nylon mallet. Check the rafters are all square to the ring beam and ridge, and then tighten all roof fixing nuts.

11. Locate the nylon bar through the spider and lock off using nuts and washers either side of the spider. The nylon bar should sit 5mm below the crest of the ridge profile.

12. Position the spider bottom cap and fix using the decorative boss onto nylon threaded bar. Note the nylon bar may require trimming down in length.

13. Fit the glazing end closures to the glass and run a bead of sealant between the profile and top pane of glass as shown above. Only use a suitable sealant with self cleaning glass. Soudal SMX 506 is recommended.

14. If not already fitted, fit the glazing bar end caps and glazing stops. Then peel back two inches of eaves beam seal tape film and fold to the outside. Insert glazing unit ensuring equal coverage and ensuring the glass is resting onto the glazing stops.

15. Fit the foam bung and clamp plate and tighten M10 nut until the foam is firmly pressed down onto glazing.

16. Fit the rafter and hip top caps using a nylon mallet, then ensuring the glass is positioned correctly, peel the remaining eaves beam seal tape film away and press glazing down to ensure contact with eaves tape.

17. Seal around perimeter of the foam bung where it intersects the ridge glazing seal, glass and glazing bar top caps.

18. Seal around rafter top caps to ridge glazing trim. Only use suitable sealant with self-cleaning glass. We recommend Soudal SMX 506

19. Seal the rafter top cap to hip top cap from the gasket intersection to foam bung.

20. Using a suitable high-grab adhesive sealant, run a small bead on the perimeter edges of the top cap and a larger bead further inboard as shown.
Note: Do not run the sealant to the bottom edge around the hip/rafter area to ensure the sealant does not touch the glass. Always ensure hands are cleaned as to not contaminate self cleaning glass.

21. Splay the top cap and lower onto the ridge whilst checking the capping is positioned correctly over the rafter and hip top caps. The capping returns should clip under the ridge profile when positioned correctly.

22. Ensure the capping is seated down correctly and remove any excess sealant from all edges.

Jack Rifters

On point 9 we mention fastening the central rafters to the spider. To install the jack rafters you must firstly, locate the jack rafter tenon onto the jack rafter fixing bolt and adjust the lower nut to align gaskets, before tightening the the top nut. Then seal the jack rafter internally to the hip.

Seal jack top capping joints. Only use suitable sealant with self-cleaning glass. We recommend Soudal SMX 506.



By the end of it you will have a stunning looking room that is full of light, openness and space. This will give guests a sense of the wow factor.

Roof Lantern Swansea Roof Lanter