Crawl Space (Inside)

Key prerequisites for the proper functioning of the Pordrän system

The following instructions must be followed and implemented before, during, and after the installation of Pordrän to ensure proper and correct operation. 

• Complete all necessary preparatory work before laying Pordrän on the ground.

• Clear the crawl space of organic debris, such as wood and other trash. Level the ground surface. No drainage layer is needed in the crawl space.

• Treat any mold infestations. Use appropriate products and always follow the manufacturer’s safety instructions. For extensive infestations, consult a professional.

• Remove the existing insulation from the floor joists.

• Carefully seal any cracks, gaps, and other openings in the floor joists.

• Use Pordrän sealant to seal cracks and joints in the foundation walls.

• Close and seal all vents in the foundation walls. Install negative pressure ventilation according to the instructions. In this case, it is possible to use an existing vent. If the building is exposed to soil radon, conduct a radon measurement after the moisture barrier has been completed. If radon levels remain elevated, contact an expert for advice.

• Negative pressure ventilation

  Even though the crawl space stays warm and dry, emissions such as radon and earthy odors can seep up. This can be remedied by installing negative-pressure ventilation with a fan. For best results, the fan’s speed should be adjustable.

• If you want to monitor relative humidity and temperature, install a humidity and temperature sensor. Place the sensor on the underside of the floor joists, on the north side where it is usually the most humid and cold.

• While in storage at the construction site, the panels must be protected from physical damage and weather exposure. With Pordrän , you Pordrän backfill using existing material, even large stones and frozen soil. Stones larger than 100 mm must be placed on the trench slope and must not come into contact with the Pordrän panel or the geotextile.

NOTE: Before you begin, please read the prerequisites and all the steps in the instructions carefully.

1. Cover the ground (which should be level and free of organic matter and debris) with weather-resistant, vapor-proof plastic sheeting. Let the plastic sheeting extend about 30 cm up the outer walls. Make a hole in the sheeting every square meter, with a diameter of 2–3 cm. If the ground slopes, it is sufficient to make holes only at the lowest points.

2. Lay down two layers of Pordrän panels. The second layer should be laid so that the joints are staggered.

3. Attach two layers of 100 mm cellular plastic panels to the exterior walls. Install the first layer of cellular plastic against the exterior wall using Pordrän —1–2 per panel. Drill through the panel into the wall using an 8 mm drill bit. Attach the second layer to the first layer using Pordrän . Use 5 clips per panel.

4. Insulate the joist floor completely against the exterior walls, 500 mm from the inside of the exterior walls. If underfloor heating is installed, insulate the rest of the joist floor with 70 mm of insulation. If there is no underfloor heating, leave the remaining joist floor uninsulated.

5. Install a negative pressure fan; a suitable model is the Östberg KVFU EC wall fan. Contact a professional if you are unsure. All electrical installations must be carried out in accordance with the Swedish Electrical Safety Authority’s regulations.