Yes, and on a long room it is frequently the better decision. Two lanterns spaced along a kitchen light it more evenly than one large one in the middle, stay within standard sizes so the frame sections remain slim, and give the ceiling two lifts rather than one. What it costs is a second opening and a second kerb.
Why two light a room better
Because light falls off with distance.
One lantern in the centre of a long room throws a bright patch beneath it and leaves both ends comparatively dim, where two spread the same glass across the plan.
The room reads as evenly lit rather than as having a bright spot.
Shadow from two directions
The less obvious advantage.
Two sources fill the shadows each other casts, so an island or a table beneath them is lit from both sides rather than one.
In a kitchen with tall units that is worth a lot.
Why the frame stays slimmer
Because the spans stay short.
Two standard sized lanterns keep their rafters within the comfortable range for slim sections, where one very large one needs deeper bars or an intermediate structure.
The limits are on how big can a roof lantern be.
Standard sizes rather than bespoke
Where the cost argument can go either way.
Two standard lanterns are often less than one large bespoke one, though there are two kerbs and two openings to build, so the comparison is job by job.
What each part costs is on how much does a roof lantern cost.
What the structure has to do twice
Two openings, two sets of trimming.
Each opening interrupts joists that have to be carried into new members, so the structural work genuinely doubles even though the access does not.
What only happens once
Access, protection, setting out and the visit.
Both lanterns go in on the same programme with one scaffold and one set of deliveries, which is why doing them together is far cheaper than doing them a year apart.
Leaving structure between them
The point that decides the spacing.
The joists between the two openings are what carry both sets of trimming, so there has to be a meaningful run of unbroken structure between them.
It is set out from the joists rather than from the room.
How far apart they should sit
Far enough to read as two, evenly placed.
Equal margins at each end of the room and a comfortable run of ceiling between them is what makes an arrangement look intended rather than accidental.
Three lanterns
Where rhythm starts to matter more than spacing.
With three, the eye reads the intervals rather than the units, so equal gaps look deliberate and one odd gap looks like a mistake whatever the reason inside.
Lining up with what is below
The detail that makes a ceiling look designed.
Lanterns centred on an island, a table or a run of units read as part of the room, and ones placed only where the joists were convenient rarely do.
Both constraints are reconciled at survey.
Matching the two
Order them together, always. Coating batches vary slightly within the same nominal colour, and two lanterns ordered a year apart can differ enough to notice on one ceiling.
What to choose is on what colour should a roof lantern frame be.
Matching the pitch
Easy to get wrong on two different sizes.
Two standard lanterns of different plan sizes may come at different standard pitches, and two different ridge heights on one roof looks unresolved from the garden.
It is checked before ordering.
How it looks from outside
Two structures rather than one, which is a real difference.
From an upstairs window a pair of lanterns is a more complicated roof than a single one, and on a small extension that can be too much.
It is worth looking from the bedroom before deciding.
Two flat rooflights instead
The quieter alternative. Two flush units light the room just as evenly, stand almost nothing above the roof, and cost considerably less, at the price of the ceiling height a lantern gives.
The comparison is on what is the difference between a roof lantern and a skylight.
One lantern and one flat rooflight
A mixture that works better than it sounds.
A lantern over the dining end and a flush unit over a utility or a hallway is a sensible specification where only one part of the plan wants the feature.
Matching the frame finishes is what holds it together.
Heat loss with two
Assessed as a total. Two lanterns are two glazed areas, and the regulations look at the whole glazed area of the extension rather than at any one element.
The limits are on can a rooflight be too big for building regulations.
Overheating with two
More faces, more sun. Two lanterns present twice the glass to the afternoon, so the case for solar control glass is stronger rather than weaker.
That is on will a roof lantern make the room too hot.
Two opening panes
Worth pairing if either is powered. Openings in both lanterns on one control system give genuine cross ventilation across the room and run from a single handset.
How we set it out on a lantern
We set out from the joists and then check the ceiling from where people will stand, because a pair that suits the structure and a pair that suits the room are settled together or not at all.
The whole picture is on the roof lantern installation page.
Thinking about this job? We survey across Worthing, West Sussex and the South Downs and give you a fixed price before any work starts, with a 10-year workmanship guarantee.