When insulating a roof, this is often what is called post-insulation. There are legal requirements that if you replace your roofing or change the roof structure, for example by adding an extension, then your roof must be post-insulated. However, this only applies if the post-insulation is profitable for you. However, this is often the case.

In a few cases it is possible to insulate yourself, but it is always recommended to have a professional do the work. There are several reasons for this. First of all, a professional knows better than anyone else where in the roof construction it is advantageous to intervene. Roof insulation done from the outside is clearly the method people recommend using, and it is advised never to intervene yourself. Furthermore, inadequate post-insulation can result in moisture damage. For the same reason, you should always contact your insurance company so that they know of your intention to post-insulate. This should be done regardless of who is doing the work.