Roof renovation with simultaneous roof insulation makes sense

If a renovation is pending anyway, you can have a roof insulation with you. What offers itself as Dämmmaßnahme here, and why, you can read here. In addition, which types of insulation bring which benefits, and where the costs pay off.

Possibilities of roof insulation

There are many ways to insulate a roof:

  • on the rafters
  • between the rafters
  • under the rafters

When it comes to which roof insulation is most effective and most recommendable, there is a clear winner: the Aufsparrendämmung. However, it also causes significantly higher costs than the other two types of insulation.

Roof renovation and roof insulation at the same time

If there is a new covering of the roof, the Aufsparrendämmung offers. The expensive costs that are incurred for uncovering the roof otherwise are not given in this case.

This is an economical insulation with high efficiency and high security in any case. In other cases, a Aufsparrendämmung, however, will be difficult to carry out economically, since the up and re-roofing of the roof clearly causes too high costs.

The advantage should be used in any case, when the roof is newly covered.

Implementation of on-roof insulation

There are two options for this: Either a full board is installed on the roof and insulated there, or it is immediately worked with dimensionally stable insulation boards. The dimensional stability of the plates must be very high (one speaks of a high "staying power").

The intense temperature fluctuations and humidity changes to which the panels are exposed may lead to deformations even over long periods of time.

Which of the two options is more advantageous depends on the particular roof and its characteristics. Good advice is advantageous here in any case.

Together with the attachment of the insulation is the attachment of a vapor barrier (on the underside of the insulation boards). The insulation itself must also be protected with a sub-roof from the weather.

Careful execution creates an airtight hood with excellent insulation effect, which has no cold spots, and thus works optimally. Thermal bridges in rafters and partitions are already avoided by the construction itself.

Effectiveness in comparison

Calculating savings is generally problematic. You always have to face each other in individual cases heating and insulation.

The more efficient and cost-saving the heating works (such as biomass heating compared to oil and gas), the lower the savings will be. There is also the risk that the insulation measure will not pay off financially.

Of course, this is offset by the legal requirements imposed by the EnEV. In the case of pitched roofs, U-values ​​of less than 0.24 W / (m²K) must be achieved in any case according to the EnEV 2014. On the other hand, if one considers the total energy consumption of the house, a roof insulation can, of course, save a great deal.

The economy of Aufsparrendämmung is usually given only from large to very large roof areas. With a roof area of ​​100 m², only about 25% higher savings are possible (with classic oil heating) due to the rafter insulation than for under and intermediate rafter insulation.

To balance this difference with the higher costs, the roof area must be correspondingly large. The usual roof sizes of 30 - 50 m² for typical single-family homes are often at the limit of profitability.

However, if one faces the direct costs, because a new roofing takes place anyway, the Aufsparrendämmung certainly worth. A significant saving in heating costs is then given.

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