ᐅ Renovating Roof Insulation Due to Building Energy Regulations?

Hello everyone,

unfortunately, I’m having trouble understanding the building energy regulations. The issue concerns roof insulation when taking over an existing property.

We have found a house from 1965 for which the energy certificate recommended insulating both the roof and the basement ceiling. We later discovered that the roof was fully insulated in 2000. Does the insulation requirement mean that I have to replace the existing insulation, or does it only apply to roofs that are not yet insulated?

Thank you in advance.

The Building Energy Act requires that within 2 years of property transfer you must:

1. Bring the roof or the top floor ceiling to a U-value below 0.24 W/m²K (1.34 Btu/(h·ft²·°F)) (§47 para.1). If the existing value is already better, this does not apply.
2. Insulate pipes carrying hot water (§69 para.2, possibly also para.1).
3. Replace heating boilers installed before 1991 (§72). You need to check if this actually applies, as there are several exceptions listed in para.3.

This only covers what you must do. What you want to do is where it really gets complicated. Be careful when renovating: if more than 10% of a building element, e.g., the facade, is altered, the element must be upgraded to meet the Building Energy Act minimum standards (§48 in conjunction with Annex 2).

Hello and thank you very much for the detailed reply. How can I determine if I achieve the 0.24 value? I don't have any data on the existing insulation material. Attached is a photo of the insulation. However, it is difficult to photograph due to the construction work.

Here is a second picture. It looks like there is over 20cm (8 inches) of insulation material.

I can already hear the typical bureaucratic complaints.

Everything is factually and technically fine, but without certification. That wasn’t required back then. Now, you probably need to have an expert report with material testing done because of the building energy regulations. If in doubt, remove the proper insulation and, if in doubt, reinstall the same insulation. However, this time with insulation values and proof of origin, and so on.

My advice: just leave it as it is.

Hello and thank you very much for the tip. When I enter everything into a calculator, I also get the thermal conductivity value.