Traditional hardwood orangeries provide an elegant alternative to a fully glazed conservatory, especially on classical older buildings.
Unlike a conservatory, which by definition has 75% or more of its roof glazed, an orangery typically has a part flat roof and one or more glazed lanterns. What’s more, by reducing the glazed area the orangery becomes more like a room, but with a special ambiance created by the glazed lantern in the roof. Because of the reduced glazed elements within an orangery, it is classed as an extension and requires full building regulations.
An orangery with its flat roof and one or more roof lanterns will protect the interior from excessive heat and if it does get hot, the rising heat will be ventilated through the roof lanterns.
The walls and flat roof of an orangery will provide more insulation than an all-glass extension. You’ll still enjoy plenty of natural light through the sides and the roof lanterns and you can use low voltage, down-lighters in the ceiling to create atmosphere and light the orangery at night.
An orangery does cost more to build, because of the increased time and material costs in its construction and the fact that all aspects of the work are subject to a Building Inspector’s scrutiny. Most people don’t realise that the glazed lanterns can be anything between 400kg and 2,000kg (eg. typically over a ton in weight). Therefore they require a roof structure designed and calculated to take that weight, typically using steel or structural glulam beams. All Richmond Oak structures are calculated by a qualified structural engineer.
The orangery has not only to meet structural requirements, but it must also meet the stringent requirements for insulation with between 100 and 140mm thickness within the floor and roof. Whilst, lead is sometimes used to cover the flat roof, because of the much increased cost and risk of theft, it is normally only used on listed buildings. Nowadays, it is deemed better to use GRP or a single layer roofing material such as Resitrix or Sarnafil. These materials will have BBA certification stating they have an anticipated life span in excess of 30 years.