Internal basement waterproofing

The basement is waterproofed from the inside without excavating the soil around the building. This means that the basement is permanently waterproofed without the necessity to do any sort of earthwork. This type of waterproofing can be done even when the
wall has active leakages. The waterproofing against pressurised water is achieved with a special coating system. Furthermore a diffusion-open restoration plaster is applied after successful waterproofing.

Koster Aquatecnic Ltd advice sheets give practical information on internal basement tanking.  Please click on the link to display in a new window:-

Advice sheet 1: Negative side waterproofing - A step by step guide to using KOSTER Mineral Systems.

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Internal basement waterproofing on foundation plate with mineral systems

Mineral waterproofing systems have the advantage of excellent bonding properties of the waterproofing material to mineral substrates, the bond between the individual waterproofing layers is excellent too. The longevity of such systems is ideally the lifetime of the building.

To avoid moisture rising through the wall due to capillary action, it is necessary to install a horizontal barrier beneath the wall made from KÖSTER NB 1 Grey (mixed with KÖSTER NB 1 Flex) or the crack bridging material KÖSTER NB Elastic.

To harden the substrate the bottom slab is primed with KÖSTER Polysil TG 500. At the wall floor junction a fillet made from KÖSTER Repair Mortar is installed to prevent stresses in the following waterproofing layers.

The area waterproofing is normally achieved with KÖSTER NB 1 Grey mixed with KÖSTER NB 1 Flex. For an extra fast application KÖSTER NB 1 “Fast” is the product of choice. In case of pressurised water the waterproofing needs to be done with the KÖSTER KD System. KÖSTER SL Premium is ideal for protecting the surface.

Alternatively the crack bridging waterproofing products KÖSTER NB Elastic Grey, KÖSTER NB Elastic White or KÖSTER NB Elastic 1C White can be used to waterproof the floor slab.

Always adhere to the specifications in the respective Technical Guidelines.

Internal basement waterproofing on the foundation plate with cold-adhesive waterproofing membranes

Fast, easy application without long waiting times: Waterproofing of the floor slab with KÖSTER KSK cold applied, self adhesive waterproofing membranes.

To avoid rising moisture, it is necessary to install a horizontal barrier underneath the wall with KÖSTER Fix-Tape AW 10 Elastic. At the wall floor junction a filled made from KÖSTER Repair Mortar has to be installed to prevent stresses in the following waterproofing layers.

The priming is done with the solvent free KÖSTER KSK Primer BL. As a standard the primed surface of the floor slab is waterproofed with the cold applied, self adhesive waterproofing membrane KÖSTER KSK SY 15. Overlap the joints 10 cm.

The applied KÖSTER KSK Membranes have to be protected from mechanical damage as work continues. It also needs to be connected to the vertical waterproofing of the adjacent walls.

Always adhere to the specifications in the respective Technical Guidelines.

Internal basement waterproofing in case of ground moisture non pressurised and pressurised water

Retroactive waterproofing in existing buildings needs to be done with mineral waterproofing systems. They have excellent bonding characteristics to mineral surfaces and also won’t detach from wet and moist substrates.

The material is applied to substrates that have to be sound and solid as well as free from bond inhibiting agents. Older plaster coats have to be removed and joints raked out and all loose particles have to be removed. As primer KÖSTER Polysil TG 500 is used. It hardens the substrate as well as reduces the mobility of the salts. Masonry repair and the installation of a fillet at the wall-floor junction is done with KÖSTER Repair Mortar Plus.

KÖSTER NB 1 Grey is used as the waterproofing layer. For a faster installation use KÖSTER NB 1 ”Fast”. To harden the material, KÖSTER Polysil TG 500 is sprayed on top of the slurry. To get a lighter surface finish use KÖSTER NB 2 White for the final coating.

Pipe penetrations are waterproofed using KÖSTER KB-Flex 200 and sealed with KÖSTER KB-Fix 5.
 
In the case of damage to basement walls caused by moisture generally KÖSTER Restoration Plaster should be applied. KÖSTER Restoration Plaster is especially designed for the restoration of masonry with high salt and moisture contents. KÖSTER Restoration Plaster helps to dry out the wall and it absorbs remaining salts. It doesn’t contain lime or gypsum, is open to water vapor diffusion and creates a healthy and comfortable room climate.

Before the application of the main plaster coat, a plaster key made from the chosen KÖSTER Restoration Plaster mixed with KÖSTER SB-Bonding Emulsion is applied first to provide a larger surface area and ensure an optimal bond to the substrate. KÖSTER Restoration Plasters are available in different varieties (grey, white, fast and light). KÖSTER Restoration Plaster 2 White is often used in older buildings without subsequent painting. KÖSTER Plaster Coat creates a very smooth surface and can be applied when desired to meet architectural goals. KÖSTER Restoration Plasters can only be painted over with breathable (open to vapor diffusion) paints such as KÖSTER Silicon Paint White or KÖSTER MF1.

Always adhere to the specifications in the respective Technical

Internal basement waterproofing in case of active water ingress

A very difficult situation: The basement waterproofing has to be done from the inside but the water is actively entering the building. Often the only solution is the KÖSTER KD-System.

KÖSTER KD 2 Blitz powder is applied directly by hand to the active leakage. The powder reacts within a few seconds and forms a waterproof mortar. When the active leakages are stopped the waterproofing layer of KÖSTER KD 1 Base, KÖSTER KD Blitz powder and KÖSTER KD 3 Sealer can be applied.

The material is applied to substrates that have to be sound and solid as well as free of bond inhibiting agents. Older plaster coats have to be removed and joints raked out and all loose particles have to be removed. Generally the substrate is primed by pre-wetting. Repairs and the installation of the fillet at the wall-floor junction are done with KÖSTER Repair Mortar Plus.

KÖSTER KD 1 Base is applied as the waterproofing layer and is brushed onto the substrate. KÖSTER KD 2 Blitz Powder is rubbed onto the still wet surface, immediately creating a dry waterproofed layer. To harden and to strengthen this layer the third part of the system, KÖSTER KD 3 Sealer, is applied. To waterproof the Basement completely another two layers of KÖSTER KD 1 Base is applied over the first layer. Pipe penetrations are waterproofed with KÖSTER KB-Flex 200 Sealing Paste and plugged with KÖSTER KB-Fix 5.

In the case of damage to basement walls caused by moisture generally KÖSTER Restoration Plaster should be applied. KÖSTER Restoration Plaster is especially designed for the restoration of masonry with high salt and moisture contents. KÖSTER Restoration Plaster helps to dry out the wall and it absorbs remaining salts. It doesn’t contain lime or gypsum, is open to water vapor diffusion and creates a healthy and comfortable room climate.

Before the application of the main plaster coat, a plaster key made from the chosen KÖSTER Restoration Plaster mixed with KÖSTER SB-Bonding Emulsion is applied to provide a larger surface area and ensure an optimal bond to the substrate.

KÖSTER Restoration Plasters are available in different varieties (grey, white, fast and light). KÖSTER Restoration Plaster 2 White is often used in older buildings without subsequent painting. KÖSTER Plaster Coat creates a very smooth surface and can be applied when desired to meet architectural goals. KÖSTER Restoration Plasters can only be painted over with breathable (open to vapor diffusion) paints such as KÖSTER Silicon Paint White or KÖSTER MF1.vapor

Always adhere to the specifications in the respective Technical Guidelines

 

 

 

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