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Do I need a vapour control layer when internally insulating a wall?

Chris Brookman
Member Admin

Sometimes. When using wood fibre systems up to 40/50mm you usually don’t need to as there is still enough heat flow through the wall to prevent issues with condensation. However, as you move up above these thicknesses then you do start to require one and the colder the location, the more you will require it.

In addition, the lower the density of your insulation, the more reliant on a vapour control layer you become and so when insulating internally, higher density products perform better and can tolerate higher moisture levels. This is because they are able to store more moisture without it causing damage to the insulation material itself.

Topic starter Posted : 09/03/2021 5:42 pm

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