A small building does not always need the same insulation as a heated house. A garage, storage room and summer cottage have different sources of moisture and different patterns of use. A cost-effective renovation starts with defining the objective. Only then are the material, thickness and scope of work chosen. The cheapest board does not have to give the cheapest result. Possible objectives are shorter heating-up times for the interior, reduced losses during operation or a more stable temperature. In an unheated storage room, insulation alone will not ensure a positive temperature throughout the winter. It slows down heat exchange but does not generate heat. If stored items must not freeze, heating must also be considered.

A quick result is only valid if the input data are correct. When selecting insulation, you need to know the wall layers, their condition and the conditions of use. A simple calculator helps compare thicknesses. However, it does not replace the assessment of moisture, thermal bridges and details. Particular care is needed with internal insulation. Prepare the layer build-up from the inside to the outside. Record their thicknesses and thermal properties. For an existing wall, the material must be identified accurately. The information “brick” alone is often too general. Include renders, gaps and existing insulation. Do not replace unknown data with the most favourable value from a catalogue.