Mono-pitch roof lantern on a rear extension: position, size and pitch

Why does a mono-pitch roof lantern suit a rear extension so well?

A rear extension is usually a rectangular room with a flat roof, often 2.5 to 4 metres deep. A mono-pitch roof lantern fits it naturally: one pane of glass lying low and calm in the roof. Inside, you get a strip of daylight across the width of the room.

Even so, a mono-pitch lantern is not always the best choice. If the old rear wall rises well above the extension and you want the glass to finish right against it, a wall-abutting lean-to on the extension makes more sense. If the extension is very wide and deep, also consider a gable or hipped lantern, as these bring light in from more sides. An overview by roof type is on roof lanterns for rear extensions.

Which size should you choose for the extension?

Decide on the position first: as close as possible to the old rear wall, because that is where the living room is darkest. Leave space between the lantern and the roof edge for the roofing and drainage.

DagLichtDesign makes a mono-pitch lantern up to 5 metres wide in a single panel without an intermediate bar. On a wider extension, a thermally broken bar is added. What that means for the view is explained in with or without an intermediate bar. The lantern has a standard pitch of 8°, ample for good drainage. More on this in choosing the right pitch.

• Position against the old rear wall, where it is dark
• Stock sizes of 1, 2 and 3 metres for quick delivery
• Up to 5 metres wide without an intermediate bar
• Standard pitch of 8° for drainage

How is it connected and which glass should you choose?

The lantern sits on an upstand that your builder constructs and insulates on the roof. On most extensions this is EPDM; the detail is covered in connecting a roof lantern to EPDM. Water runs off the low side of the glass onto the flat roof and follows the fall to the existing downpipe.

If the extension faces south, HR++ double glazing is more than enough for a living room or open kitchen, possibly with a solar control coating against heat. If the back of the house faces north or west, triple glazing is a serious option. The quote shows them side by side.

Delivery, fitting and what to send for a quote

Made-to-measure is ready from 2 weeks after approval. Collection in Barneveld is by appointment, delivery on an agreed date. Your builder works from the printed and digital installation manual. Fitting by the regular installation partner is also possible, as a separate line in the quote. What the extension itself roughly costs is covered in costs of an extension with a roof lantern.

• Photo of the extension and the old rear wall
• Internal dimensions and the preferred position
• Roofing: EPDM, bitumen or zinc
• Orientation to the sun and your glass preference

Frequently asked questions