How often should you replace attic insulation

Is it worth replacing an old roof insulation?

Answer by Andreas Skrypietz from the German Federal Environment Foundation (DBU)

These questions cannot be seriously answered from a distance! But I still want to give some pointers. Whether the installed insulation still works depends solely on whether it is still intact as insulation, i.e. as a largely homogeneous layer. Without a major structural effort, this can only be determined by means of thermography. If thermography reveals that the insulation has gaps or other imperfections, then it will be interesting to think about the second question. Insufficient insulation can only partially fulfill its function and the energy saving effect is correspondingly reduced. Depending on the extent of the imperfections, it can make sense to renew the insulation. But be careful: When renewing the insulation, you must comply with the requirements of the current energy saving ordinance! That means a U-value of 0.24 W / mK. Whether you can achieve this with the existing rafter thickness can only be calculated after knowing these details.

If the existing insulation appears intact after a thermography, I would advise you not to do anything on the roof. One exception: the top floor has been expanded and I assume it is heated. If you notice when using the attic in winter that there are drafts, the indoor climate is rather uncomfortable and the heating only gets the rooms warm with difficulty, then the intact insulation seems to be insufficient in its insulation thickness and you should have one Think about renewing or improving the roof insulation. Depending on the object, roof construction and the existing construction and installation of the insulation, it may also be possible to improve the performance of the existing insulation by subsequently blowing in cellulose. However, this can only be decided by a specialist and after a detailed on-site assessment.

All in all, I can only advise you to look for a specialist on site. Because for such questions it is imperative to have detailed knowledge of the local situation in order to find feasible and economically sensible solutions.

Please note: Our "remote" expert advice cannot replace an on-site appointment with an energy advisor or expert. We answer all questions to the best of our knowledge, but not legally binding, and assume no liability. The experts provide an indication of what a solution to the respective problem could look like and which questions the homeowner still needs to clarify.