Improved thermal efficiency of dwellings: filling spaces
To improve the thermal efficiency of a dwelling, in addition to isolate it from the outside with an insulation system, you can perform a filling spaces. Among the most widespread techniques for realization of the infills, there is in fact one that has two layers of bricks separated by an air gap. Wanting to improve the thermal resistance of an existing perimeter wall, it can act on this air gap filling it with a suitable insulating material.
The realization techniques of filling the interspace are usually three and differ according to the type of injected material.
1. Loose material
Holes are bored 2 meters away from the top of the wall and is insufflated of the loose material inside the cavity which, in order to use this technique, it must have a minimum thickness of 5 cm. Before carrying out the filling operation, you must ensure that the garments have a compressive strength as to withstand the pressure caused by the installation of the insulation. Possible materials to be used are vermiculite, cork, polystyrene, cellular glass, foamed clay ... (top image)
2. Material initially liquid
To inject material initially liquid, such as polyurethane resin, urea (less expensive than the first) or formo-phenolic, the minimum thickness of the interspace must be 3 cm. Even in this case a hole is drilled in the upper part of the wall after verification of the compressive strength of hangings.
Two small defects common to both techniques so far analyzed: the need to completely fill the gaps when it might be enough existing lower thickness of insulation and the difficulty of controlling the proper performance of the finished work.
3. Rigid sheets
While the first two cases are well suited to existing walls, for this third party, at least one of the two layers of the double lining must be of new invoice. The third technique consists in fact in positioning between the inner liner and outer, rigid sheets of insulating material (polystyrene, polyurethane, mineral fiber, etc.).
ADVANTAGES AND DISADVANTAGES
But we move on, as usual, to analyze the advantages and disadvantages of this system of thermal insulation. In favor of the isolation system for filling of cavities, there is the protection of the insulating material from the atmospheric agents, the simplicity of realization and the reduced cost of installation, the raising of the mean radiant temperature of the outer walls with a consequent improvement of thermal comfort of the occupants.
The cons, instead (in addition to those relating to only the first two cases), are the reduction of the thermal inertia of the walls, the increase (compared to the interspace empty) of the stresses of the hygrometric external curtain with risk of condensation and the increase the effect of thermal bridges.
25/11/2009
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Translated via software
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Source:
Italian version of CercaGeometra.it