ᐅ Attic Insulation: Opportunities for Improvement in Existing Insulation

Hi everyone,

I bought my first home 6 months ago, and now we are looking at what needs to be done. We noticed that the attic is very cold (about 2-5°C (4-9°F) warmer than the outside temperature, but 10-15°C (18-27°F) cooler than the indoor temperature).

It seems that the attic is insulated on the sides with 13-20cm (5-8 inches), depending on where you measure and how much it’s compressed, of glass wool insulation, but in some spots some material appears to be missing or has fallen down. From your experience, how much percentage of heating costs can I save, and what would be sensible to do?

a) Just seal the gaps where the insulation is missing
b) Add another 10-15cm (4-6 inches) of insulation
c) Use a different material (although mineral wool like rock wool is apparently not much denser according to online sources)
d) Something else I might not have considered yet? (Stone walls, floor)

To be honest, it looks a bit like there have been moisture issues there. It appears to be water stains. Perhaps the insulation was removed because of that?

Additionally, the insulation should not be heavily compressed, and the vapor barrier should be properly sealed to be airtight. It definitely shouldn’t be like this. As long as everything stays dry, I wouldn’t worry too much. However, I would actively monitor the area and check if moisture is still accumulating. Depending on the type of vapor barrier, the mineral wool insulation should have some spacing to allow ventilation and drying.