Upgrading a building is an extremely complex operation. The first choice that must be faced concerns about whether to intervene on the interior or also on the exterior, an option that requires, in most cases, changes to the aesthetics of the building. This problem essentially concerns historic buildings, with valuable decorations, which can not be in any way be affected. Besides, the external energy requalification, while ensuring greater results in terms of energy savings, involves higher costs (both materials and labor) and longer working time.
Here then are some proposals on what solutions to adopt.
External insulation
It consists of the application of insulating panels, by gluing and mechanical fixing with wide-headed plugs (thermal break), on the outer surface of the wall previously prepared and finished with plaster skimming multi-layer with a glass fiber network in between. Insulating materials of different nature can be used (fibrous or cellular, natural or synthetic) taking care to choose invariably both the glue and the skim coat.
Internal insulation
It consists of the application of composite panels (insulation and plasterboard with a vapor barrier) by gluing and fixing on the inner surface of the infill walls, or in the thickness of the plasterboard substructure. Finishing is achieved by grouting the plasterboards. An interesting application involves the use of heat-reflecting materials, characterized by high thermal performance and reduced thickness; these materials must be installed between two air gaps. With this solution, the wall remains cold and therefore there is a frequent risk of interstitial condensation; it also determines a reduction of the net internal volume of the rooms.
Insulation in cavity
It consists of the application through insufflation of loose insulating material directly into the cavity of the cavity walls; this operation is performed with special machines capable of "blowing" the insulating material through holes with reduced section. This system, particularly economical, does not allow the correction of thermal bridges, and in some cases may lead to the appearance of mold and stains on the inside of the wall.
Floor insulation
Floor insulation on unheated rooms can be carried out above or below the floor slab. It can be carried out on any type of support after suitable preparation. When working on floors or slabs against the ground, it is advisable to create an aerated crawl space to avoid direct contact between the structures and the ground: prefabricated shaped elements are usually used which, placed on top of a horizontal plane, create a space for air circulation, detaching the building from the ground.