Rafter insulation – space saving and energy efficient
In the course of the new regulations on saving energy and in view of steadily rising electricity and gas prices, sufficient insulation methods are becoming increasingly important. Especially in new buildings or apartment buildings, attention must be paid to efficient thermal insulation in accordance with the EnEV in order to comply with legal requirements. But regardless of whether it is a new building or whether an already existing building should be renovated – if you invest in proper thermal insulation, you can save on heating costs in the long run and also gain in living comfort.
When it comes to the efficient insulation of the roof truss, different methods are available. There is, for example, the sub-rafter insulation, in which the roof truss is provided and covered with insulating material inside and below the rafters. Often already pre-made plate systems are offered, which can be installed with little effort by the handy home improvement itself. This method is ideal for insulating the roof structure at a later date, and the costs remain within manageable limits. The big disadvantage of this insulation variant, however, is the loss of space, which comes into play particularly when the attic is to be used as a living space. Another possibility is the intermediate rafter insulation, here – as the name suggests – the insulation material between the beams attached. Here, however, it may happen that the rafters are not as thick as the insulation material and therefore need to be reinforced, which is associated with additional effort. In addition, here also the rafters usually have to be dressed in addition, which in turn draws the disadvantage of loss of space. Another problem is thermal bridges, which are caused by the interruption of the roof insulation by the rafter beams and thus can lead to heat loss. Advantages of this method are, in turn, the low cost and the ability to obstruct the insulation without any problems later. The third and best in terms of building physics is the rafter insulation.
Ideal for new buildings – the Aufsparrendämmung
In insulation on the rafters, the insulating layer is applied to the roof truss from the outside, the roofing then takes place directly on the insulation. For a new building, this method is ideal, because here anyway the roof must be covered. From a thermal point of view, rafter insulation is the best method, no thermal bridges can be created here, which leave valuable heat to the outside. Even those who want to use the attic for living comes with this insulation method to an increase in living space. Finally, there is also the visual aspect – the rafters remain open, which many see as an attractive design element.
Of course, the method of Aufsparrendämmung can also be applied to existing buildings in remedial measures, but here it means a significant overhead of labor and costs, since the roof must first be completely covered to apply the insulation. On the other hand, the roof can be adequately insulated without having to destroy a panel already installed inside the house. Often, owners of old buildings opt for this method, if it is planned anyway to re-cover the roof.
Rafter insulation and insulation material
Insulation material applied externally to the rafters must be able to cope with special challenges such as the extreme temperature fluctuations during the year. Therefore, builders should pay attention to a high quality of the insulation boards. Inferior material will quickly crack, which in turn can lead to heat loss. Glass and rock wool as well as polyurethane or polystyrene composite panels are available as insulation material. While glass wool offers particularly good sound insulation, rock wool is characterized by its heat-insulating properties, but its own weight is considerably higher. Which material is most suitable for which roof depends, among other things, on the load capacity of the roof.Anyone who decides on a Aufsparrendämmung should therefore necessarily consult with the expert, in order to make the right choice of materials among the many products offered in hardware stores and online stores.
After the insulation material has been applied over the entire roof, it is covered with a suitable underlay film (vapor barrier). This prevents moisture and water from entering. Then then the laying of the roof tiles. It is also possible to leave room between insulation and covering two to three centimeters to provide the necessary air circulation.
Advantages and disadvantages of the rafter insulation
The positive aspects of external roof insulation have already been mentioned. Here, the best possible thermal insulation and space savings are certainly the most important plus points. The biggest disadvantage, on the other hand, can be seen in the considerably higher costs. These arise on the one hand by higher material costs, on the other hand also by the fact that these works should rather be taken over by a roofing specialist.
However, anyone who plays with the idea to take over such work on their own initiative, should definitely seek expert advice. Numerous Internet portals offer home improvement companies the opportunity to inform themselves about various work steps, safety precautions, required materials and tools and to exchange relevant experiences. The required products can usually be obtained via online shops, often it is also possible to contact them by e-mail and to get expert advice. In portals for the exchange of experience, the input of personal data may be required, of course, then paid attention to the appropriate privacy.