Hello
We have a summer house in the style of functionalism with a low-pitched almost completely flat roof. We now want to add insulation to the roof in conjunction with applying a new waterproof layer (felt) and possibly replacing parts of the roof boards if necessary.
We believe there may be some insulation, likely wood shavings, in the "ceiling structure." The house is from the 1930s and was built as a summer cottage, i.e., not insulated for winter use.
We were suggested to add insulation from the outside with some form of insulation boards from Isover. Our idea is to have felt that meets the requirements for a waterproof roof on top. As I understood it, the recommendation was to place the insulation boards on top of the existing waterproof layer (leaking metal in our case) and apply a new waterproof layer on top. Any air gaps that might ventilate the current roof would be closed so that the roof no longer has any ventilation/air gap.
Does anyone have experience with flat functionalist roofs with limited space between the "ceiling structure" and the roof?
I can hardly find any sketches on how these should be constructed/additionally insulated and how the ventilation should be arranged, in literature or online.
The house has only been used during the summer months up until now, but we want to increase the opportunity to use it at other times of the year through gradual additional insulation.
Grateful for advice!
