In contrast to the skylight, flat roof windows always have at least one real glass pane. There are also flat roof windows with a curved plastic shell on the outside, but there is a glass pane underneath, which is why they are usually no longer called a skylight. However, some manufacturers also refer to such variants as "rooflight dome plus", "rooflight dome comfort" or similar, as the terms are not firmly regulated. Flat roof windows are usually similar to a classic roof window, with the difference that they are not mounted in the roof, but on a collar that is integrated into the flat roof waterproofing. They are available in rectangular and round versions. Flat roof windows are standard products and are always part of a modular system. They are available with fixed glazing or with opening sashes and in the nominal sizes 60 x 60 cm or 50 x 100 cm - 150 x 150 cm.
Source: bauwion
