Waterproofing of modern light well constructions

In the course of the ever-increasing demands on the thermal balance of buildings, comprehensive perimeter insulation has long played a major role. Here, it is important to avoid thermal bridges and to integrate the detail points into a modern basement waterproofing system. Until now, the thermal-bridge-free design of light wells was very complex. In the following, the innovative waterproofing solution of an insulated mounting panel with integrated light well fastening is described herebelow with the example of the company MEA Bausysteme GmbH. With the help of the 2-comp. reactive and quick-setting waterproofing coating weber.tec Superflex D 24, the basement light well module without thermal bridges is securely fixed and integrated into the wall waterproofing level on the main surfaces.

Simple & safe to the goal

  1. 1. The MEAFIX system consists of the composite insulation panel with fiber concrete layer for the light shaft, the perimeter masking frame and the light shaft element. The light well is pre-screwed after bonding and waterproofing of the composite panel.

  2. 2. After cleaning and preparation of substrate, first apply the primer for absorbent substrates weber.prim 900, diluted with water 1 : 1 in the fixing area of the board.

  3. 3. Priming of the front side of the panel.

  4. 4. This is followed by application of a scratch layer and, after its drying, by application of the first waterproofing layer weber.tec Superflex D 24. In case of pressure water, the woven glass fiber mesh weber.sys 981 is embedded full-surface in the first layer.

  5. 5. Apply a second waterproofing layer of weber.tec Superflex D 24. The surface waterproofing is carried out at least 20 cm beyond the leg lengths of the installation insulation board.

  6. 6. After the last waterproofing layer has dried, begin the work for bonding the board; for this purpose, use weber.tec Superflex D 24 as an adhesive on the substrate and also on the back side of the board (floating-buttering method), using a 10 mm notched trowel.

  7. 7. Application of weber.tec Superflex D 24 on the backside of the panel.

  8. 8. After that, the board is pressed onto the substrate "wet-in-wet" and floated in. The insulation board must be secured against slipping during the initial phase of the adhesive, depending on the board thickness.

  9. 9. A small groove of weber.tec Superflex D 24 is formed all around the inner corners. The tooth webs are filled in at the same time with the same material.

  10. 10. After the groove has dried, the front sides, the top of the insulation boards up to the window section and the transition to the wall waterproofing level are waterproofed in two layers.

  11. 11. The waterproofing of these details is done by embedding the woven glass fiber mesh weber.sys 981. It should overlap the wall waterproofing by at least 15 cm. The second layer is applied as early as possible, as soon as the first layer can no longer be damaged.

  12. 12. The waterproofed mounting panel.

  13. 13. After the waterproofing has dried completely, the light shaft element is installed. Special screw anchors are used for this. The fixing holes are additionally sealed with the glue MEA AQUA and underlaid with spacers.

  14. 14. The flange of the light shaft element is roughened with sandpaper. The glue MEA AQUA is applied all around the flange.

  15. 15. Then hang the light shaft element and fix it with screws. The joint width of the glue must not be < 2 - 3 mm. Refer to further installation instructions of the manufacturer of the light shaft system.

  16. 16. The completed detail point. This is followed by the surface waterproofing of the remaining wall surfaces, and after drying, by the perimeter insulation.