Roof insulation
The insulation of the roof is intended to reduce the heat transfer coefficient (U-value) of the roof. Roof insulation is part of the thermal insulation of buildings and, like basement insulation or facade insulation, is suitable for reducing the energy consumption of a building.
species
There are different ways to insulate a roof . These differ in terms of costs, materials and, above all, where the insulation material is installed.
Under-rafter insulation
With under- rafter insulation, the insulation material is attached below the rafters . Systems with cladding are usually offered. This saves you having to subsequently clad the rafters. Advantages of this variant are the low costs and the possibility to insulate the roof afterwards. A disadvantage is the reduction in living space due to the thickness of the insulation.
Between-rafter insulation
In the case of between-rafter insulation, the insulation is installed between the rafters. If the roof is to be used as living space, additional cladding is usually necessary here. Rafters that are too small can be problematic, meaning that the insulation is not thick enough. Here the rafters have to be reinforced. The advantages are the low costs and the possibility of retrofitting the insulation. Reducing the size of the living space can be disadvantageous if the rafters have to be reinforced if the rafters are too thin.
Above-rafter insulation
The above-rafter insulation takes place above the rafters. This type of roof insulation is most worthwhile if the roof is to be re-covered. The advantages of this variant are very good insulation properties and no loss of living space. Since the external insulation is exposed to strong temperature changes, it should be ensured that the individual panels are dimensionally stable in order to avoid the formation of cracks. The above-rafter insulation has tongue and groove. This insulating material does not require any solid wood formwork, as is the case with flat roof insulation with a rebate that is applied to the pitched roof. The significantly higher costs are disadvantageous. The insulation can also be installed in old buildings (e.g. terraced houses). However, there is of course a height difference to the neighboring house, depending on the thickness of the insulation material.
The static load transfer of the tile weight is carried out by the roof battens distributed over the entire roof, as with a normal roof covering. Only quality-tested (timber) screws may be used for assembly. You have to transfer the entire shear forces of the roof load from the roof tiles over the roof battens through the insulation material into the rafters.
Auflattdämmungen
The so-called Auflattdämmungen are a variant or further development of the above-rafter insulation. They are not only above the rafters, but also above the roof battens. The advantages are essentially the same as with over-rafter insulation, i.e. H. Complete insulation without thermal bridges, the roof structure can remain visible (easier pest control, freedom of design, more secure in terms of building physics due to fewer connections). An additional advantage of the lath insulation is, on the one hand, that the roof battens are also protected from the weather.
Flat roof insulation
Flat roofs can be insulated using three different methods, the choice of which depends on both the slope and, above all, the type of roof construction.
In the case of cold roof insulation, there is an approximately 10-15 cm layer of air between the actual insulation layer and the roof waterproofing, which serves as rear ventilation. This insulation method is mainly used for flat roofs with a wooden structure that have only a slight slope and about 30 to 50 cm space between the ceiling and the roof waterproofing.
On flat roofs with a concrete ceiling, warm roof or inverted roof insulation is preferred. With warm roof insulation there is no air layer between the ceiling and the outside of the roof. Since the insulation material is enclosed airtight between these two layers, this insulation method should only be selected if the roof has a sufficiently high level of impermeability. Otherwise, penetrating water can quickly lead to mold growth and destroy the insulation material.
costs
The cost of roof insulation can vary significantly depending on the type of roof insulation. With a simple interior rafter insulation without additional cladding, the costs are around 50 euros per square meter. On the other hand, over-rafter insulation with a completely new roof covering can cost more than 200 euros per square meter.
materials
In principle, the same insulation materials can be used as for other thermal insulation measures. Insulation boards that are easy to attach and often already contain cladding on the back are particularly suitable for under-rafter insulation. For the insulation between the rafters, insulating wool is particularly suitable , which can be easily attached within the rafters. Rigid foam systems are often used for above-rafter insulation .
Web links
Individual evidence
- ↑ Flat roof insulation. Retrieved November 16, 2017 .