Crawl space dehumidification for better climate in churches

  • Crawl space dehumidification in churches

    In 2008, house fungus was discovered in a church in Sweden and they decided to do a proper climate study of all churches in the area. The climate in the crawl space and church hall was well documented for a couple of years with measurement of moisture, temperature and mold spores. The constant high humidity in the crawl space indicated a risk of mold growth which was also found. It was assessed that rot could also develop. Another church in the area had previously suffered from the same problem. To solve the problem of moisture in the crawl space, they chose to lift the church, cast a concrete slab, which they placed under the church. A solution that was very expensive and time consuming so they wanted to avoid this method and therefore chose to try dehumidification as a permanent solution.


    It was known that beams and floors had been replaced several times due to constant high humidity in the crawl space and when it was found that the climate in the crawl space had not gotten better, they had decided that improvements to the crawl space construction would be made. The idea was to seal the foundation with plastic foil against the ground and a bit up against the foundation walls. Also the terminals for the support lines in the joists were wrapped and all air valves were sealed. At the same time, it was decided to install two of Corroventa’s adsorption dehumidifier on trial for one year. Since the installation of the dehumidifiers, the results and the changes of the climate in the crawl space have been carefully tracked. The investigation went on for 1.5 years, where relative humidity and temperature were monitored and tracked in the church’ various halls and rooms and in the crawl space. Stefan Aktander from Corroventa who participated in the project says:

    ”We knew the starting point and that the alternative was to cast a concrete slab and place under the church which would be incredibly expensive. Our alternative was instead to seal, put plastic and install crawl space dehumidifiers. It proved to be very successful and financially advantageous.”


    The result exceeded the expectations. After the measures of sealing the soil and installing the dehumidifiers, measurements basically showed a fast drying process. Not only did the climate in the crawl space significantly improved, the result was also that the church’ heating costs and the overall economy for energy consumption decreased. The indoor climate in the church became significantly better, which is of great importance for the interior of the church such as the organ and art. The dehumidifiers from Corroventa are still in operation today and the climate is constantly being measured in the crawl space. Independent of season and weather conditions, it is now too dry in the crawl space for any microbial process to start.

    About CTR 500TT

    During the project, two crawl space dehumidifiers CTR 500 TT were used. It it our largest dehumidifier for fixed installation in crawl spaces with a dry air volume of up to 500 m3/h.

    The crawl space dehumidifier is highly energy efficient with a high capacity in relation to its’ size. CTR 500TT is specially designed for use in crawl spaces, where the requirements are tough regarding robustness, operational safety and long service life.

    Some benefits with CTR 500TT:

      • Designed for foundations up to 350 m3
      • Effective against damp problems
      • High quality and long service life
      • Energy efficient and has low operating costs