SILRES® BS 375 is a solvent dilutable concentrate of Alkylsilane/siloxane. In diluted form with organic solvent, it serves as a water-repellent for impregnating mineral building materials and as a primer for mineral substrates.

It develops its water-repellent effect by reacting with atmospheric humidity and with water absorbed on the walls of the pores and capillaries of the building material.

SILRES® BS 375 penetrates the building material further and exhibits higher resistance to alkalis, than pure methyl silicone resins.

Hydrophobic impregnation / priming

The dilute solution of SILRES® BS 375, whether it is being used to impregnate or prime, is either brushed onto the building material of applied by flooding. It is usually sufficient to treat the building material twice, applying SILRES® BS 375 solution liberally and uniformly, wet-on-wet. Best results are obtained by flooding the building material.

To achieve good penetration of the impregnating agent/primer, the building material should be air-dry at the surface (to a depth of 5 mm). The area for treatment should not have any damp patches.

The amount of hydrophobic impregnating agent  / primer required for two liberal applications depends on the absorbency of the respective building material.

The following examples demonstrate this:

Mineral plaster       0,5 to 0,8 l/m²
Brick masonry       0,4 to 2,0 l/m²
Aerated concrete   0,5 to 2,0 l/m²
Natural stone         0,1 to 2,0 l/m²

When material requirements are being calculated for a bill of quantities, a sufficient large (1-2 m²) test area should be used to determine the amount of impregnating agent/primer needed. The efficiency of the treatment can also be checked on the test area.


SILRES® BS 375 can be diluted with aliphatic or aromatic hydrocarbons or with anhydrous alcohol. We would recommend the use of petroleum hydrocarbons such as White Spirit 130/175 and White Spirit 145/200 or hydrocarbons with a low aromatic content, e. g. Shellsol T. Alcohols should only be used as diluent of the impregnating agent is likely to come into contact with plastics that are attacked by solvent (foamed polystyrene, bitumen, etc.), and this cannot be avoided.
The solvent used should have a boiling range of 140-190°C and an evaporation number of 30-90. If the above mentioned hydro carbons are used, SILRES® BS 375 sould be diluted in a weight ratio of 1:11 to 1:15.


The 'Best use before end' date of each batch is shown on the product label.

Storage beyond the date specified on the label does not necessarily mean that the product is no longer usable. In this case however, the properties required for the intended use must be checked for quality assurance reasons.

Sales and support

Wacker Chemical Corporation
3301 Sutton Road
Adrian, MI 49221-9397
United States
+1  888  922-5374 (Phone)

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Brenntag North America
1 Cragwood Road Suite 302
812021 South Plainfield
1  6109266100 (Phone)
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