How to insulate a building: some advice on the choice of materials and operations to be performed
The thermal insulation of the building is an important intervention in the energy savings, and requires technical expertise in establishing appropriate material and thickness, but in view of the incentives for investment in the construction sector aimed at increased energy efficiency of the buildings we read a bit 'of what it is and how to intervene.
The type of construction or the type of insulation depends on several factors, including the preferences of the client, but to get a low-energy building is preferable to adopt specific models of construction and precise architectural forms. In this case, the compactness of the building is the first characteristic of energy saving, where the dispersive surface is reduced to a minimum and the protrusions, indentations, the joints should be avoided as much as possible.
We have seen that the decisive factor for the heat losses of our house is made up of the U-value, which depends not only on the material, but its thickness and insulation from the rest of the structure.
The supporting structure of a house can in fact be made up of reinforced concrete, steel or wood, and the roof can be done in multiple ways. While in the case of the structure the insulation is placed in the walls and in their interspace, the roof insulation is applied over, under or between the supporting beams.
The insulating material also has characteristics of mechanical strength, thermal conductivity, behavior to water and moisture, fire and dimensional stability, which must be taken into consideration. The issue of thicknesses to choose from is determined by the technicians of the sector: there are usually minimum thresholds to be respected in accordance with the building regulations and techniques, along with a thermohygrometric analysis of the walls to make sure that there is condensation inside them. In the standard are recommended at least 8 cm of insulation in at least the vertical closures.
We saw a short list of materials that are used for insulation and now let's see how to apply to buildings, preferring the energy-saving materials and not harmful to humans. Recall, however, that, in order of importance, the operations to highlight regarding the insulation of the attic, to doors, windows and glazing, perimeter walls and floors.
1. Above the supporting beams are used the expanded or extruded polystyrene, glass wool and that of rock. Other types of insulation that can be applied between the beams are hemp, cork, wood fiber, polyurethane.
2. Between the supporting beams. polystyrene foam (panels locking), linen, glass wool and rock, hemp, wood fiber, sheep wool, cellulose.
3. To isolate the last floor using polystyrene foam, hemp fiber, wood, cork, sheep's wool or cellulose.
4. To isolate the exterior walls: expanded or extruded polystyrene, hemp fiber, wood, cork, glass wool and rock mineral foam.
5. Cavity: expanded or extruded polystyrene, linen, glass wool and rock, hemp fiber, wood, cork, mineral foam, cellular glass, cellulose.
6. For acoustic insulation can be used polystyrene foam, hemp, wood fiber linen, glass wool and rock wool of sheep and cork.
7. For perimeter insulation finally use the extruded and expanded polystyrene.
8. For tubes of glass wool, polyurethane.
9. For the isolation of the inner wall cellulose, polyurethane coupled with aluminum.
10. For the floor hydrophobized polystyrene and polystyrene extruded
Deepening, as regards the insulation of the walls may be applied two types of actions:
Systems insulation
The cladding system, comprising the laying of the insulation al'esterno structures tamponade, is a kind of intervention that allows isolating the vertical surfaces also of existing buildings, even in this case are fully reassessed. The benefits mainly concern the continuity of the insulation, the correction of thermal bridges, and greater comfort in winter and summer thanks to the increase of the thermal inertia of the walls.
Insulation systems in the inner walls
The location of the insulation is assessed when considerations about the amount of accumulated heat from the wall, when we heat the house in winter, and the materials that are found inside of the insulating material. In the case, for example, in which heating is centralized in continuous operation, usually opts for external insulation, because the accumulated heat from the walls during the daytime exercise compensates the losses at night when the system is off. It isolates instead in the case of heating, where the rooms are heated and occasionally quickly you want to get a comfortable temperature in the room.
The insulation in the cavity
Usually it is an intermediate solution to the other two. This system is still the most common. The air chamber inside the wall performs the functions of disposal of water vapor and for protection from the infiltration of rainwater.
In the end it would always be isolated from the outside the building envelope always, if possible. This way you will easily get the required parameters from the energy class choice.
20/01/2012
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Translated via software
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Source:
Italian version of ReteIngegneri.it