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Forums Forums ROOFING FORUM UK Roof lantern question

  • Roof lantern question

    Posted by James Butler on January 10, 2026 at 4:01 pm

    Roof lanterns… what size is reccommended for the room? I’m planning on putting one in my 3M x 10M extension (split into 3M x 7M dining and 3M x 3M office. I’ve read online 15-20% of the roof space minimum. I’ve also seen pics of houses that are tiny and others massive! Is the 15-20% a good rule of thumb?

    Any advice and pictures please share!

    Lily Evans replied 1 month ago 8 Members · 7 Replies
  • 7 Replies
  • Joe Wild

    Member
    January 10, 2026 at 4:02 pm

    Get the biggest you can afford mate.

  • Jonathan Turner

    Member
    January 10, 2026 at 4:03 pm

    Depends how much other glass you have in the extension. Get a saps calculation done to make sure

  • Jose Rodriguez

    Member
    January 10, 2026 at 4:04 pm

    Just fitted 4.5m x 2m in our 14 x 4m and looks fantastic

    We’ve added a utility room inside so the kitchen internal size Is smaller but only 2.6x 4m

  • Keith Manning

    Member
    January 10, 2026 at 4:04 pm

    My neighbours have a fairly large one. I see them climbing the roof in the summer to cover it with ugly tent fabric. Based on this experience I’d advise to be sensible about going for the size, which is too large.

  • Lawrence Palmer

    Member
    January 10, 2026 at 4:05 pm

    I personally work out what’s looks best front underneath, how big you want the band going around etc

  • Leonard Ross

    Member
    January 10, 2026 at 4:06 pm

    Fitted 2no 1.4m x 3m in a 6m x 6m extension, looks great

  • Lily Evans

    Member
    January 10, 2026 at 4:06 pm

    Bear-in-mind…often is the case you will need steels in the roof structure for support – greatly adding to costs!

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