Paroc stonewool is the driest insulation on the market

05 Feb 2019

According to studies, only a very small number of moisture problems in buildings are due to materials suffering from short-term moisture in the building phase. The main causes for problems are construction and design faults, building use or poor maintenance. The dampness and drying of insulation and structures during construction projects has been extensively studied in research centres, on constructions sites and in completed buildings. In these comparative studies, Paroc stonewool has been found to remain very dry.

Excellent performance capacity

In a completed building, the conditions for insulation are always dry, except in underground structures. The roof and facade cladding with its details protect insulation on the outside and vapour barriers on the inside. During building use, it is important to ensure that the insulation does not absorb moisture from outdoor or indoor air, thus reducing the structure's thermal insulation.

Therefore, in the construction phase, the most important properties for insulation are low moisture absorption and fast drying. An extensive study, carried out by VTT Technical Research Centre of Finland Ltd., showed that the moisture performance of insulation materials differed.

Learn more about the study >>

According to the study, Paroc stonewool:

  • stays dry even in high humidity
  • does not absorb water
  • dries very fast
  • has no capillary rise of water

Hygroscopic balance moisture content, 98% RH (EN 12571:2013)

Savings and safety

The majority of building materials contain moisture, which must be allowed to dissipate as quickly as possible already in the construction phase. In rain or high humidity, the moisture regain of materials differs. Even if the insulation itself does not get wet, the moisture content of other structures increases. Thus, the water vapour transportation capacity of insulation plays a significant role for the drying time of structures. Insulation which does not block moisture ensures two-way drying of structures. "Insulation seldom is the cause of moisture problems, but it may have a big impact on the prevention of problems," states Application Manager Susanna Tykkä from Paroc.

According to the study, Paroc stonewool:

  • is a diffusion open material i.e. it allows two-way drying of the surrounding structures
  • minimises the drying time of concrete structures and, thus, shortens project schedules and creates costs savings.

Without mould

Mould can be found everywhere: it is in the air and exists on almost all outdoor surfaces. The small and light mould spores get in through open doors and windows, ventilation inlets and heating and air conditioning ducts. Normally only significant and toxin-spreading mould growth causes symptoms for the occupants of buildings.

Mould grows only if it has access to enough heat, nutrients and moisture. Mould starts growing if relative humidity is high (≥ RH80–85 %), the temperature is above 10 °C and it has enough organic matter for nutrient. If one of these is missing, mould won't grow.

According to objective studies and calculations, constructions insulated with Paroc stonewool stay dry even in extreme conditions. The study included 13 most typical wall and roof structures. The structures were studied in 2030 climate conditions over five years. The structures were examined at relative humidity levels of 80% (normal level) and 95 % (damp structure).

Stonewool insulation is manufactured of non-organic stone, which means it is not a favourable source of nutrients for mould. Paroc has had its stonewool tested in an objective laboratory. The test was carried out in the relative humidity of 95–100 % and the temperature of 22 °C using the most typical mould types.

According to the study, Paroc stonewool:

  • resists mould growth and does not cause mould to grow on other structures
  • contains no fire-retardant chemicals that promote corrosion in humid conditions

Further information: The driest insulation on the market
Download Paroc's moisture guide
Further information: Application Manager, Timber & Frame Constructions, Susanna Tykkä-Vedder, tel. +358 (0)40 705 4999