SILRES® BS 3003 is a water-thinnable, solventless emulsion, based on a mixture of silane and siloxane.

Diluted solutions of SILRES® BS 3003 serve as highquality, general-purpose water repellents for impregnating and priming mineral surfaces.

SILRES® BS 3003 is also suitable for the post-hydrophobation of fiber cement products, such as fiber cement boards.


SILRES® BS 3003 emulsion contains a stabilized mixture of silanes and siloxanes that are susceptible to hydrolysis. Hydrolysis occurs only after application to the substrate, which breaks the emulsion. Alcohol is released and the emulsion is converted into a silicone resin water repellent.

SILRES® BS 3003 reduces the capillary absorption of the building which it has penetrated, but does not clog pores or capillaries. There is therefore little or no impairment of the building material´s ability to breathe.

SILRES® BS 3003 shows the following special features:

  • good depth of penetration
  • resistance to alkalis
  • rapid development of water repellency
  • provides good adhesion for paints
  • water based and environmentally friendly
  • stable in storage, even when diluted

Dilute SILRES® BS 3003 is an excellent water repellent for many absorbent mineral substrates, such as bricks, sand-lime brick, natural sandstone and mineral plasters. It is not so suitable for less absorbent, dense natural stone, especially limestone and marble. Owing to its aqueous consistency and storage stability when diluted, SILRES® BS 3003 is ideal for inplant impregnation of building materials made of clay, aerated concrete, sand-lime brick, fibrous cement, mineral fibers and lightweight aggregate.

SILRES® BS 3003 may also serve as a water-repellent primer for emulsion paints and plasters, silicone resin emulsion paints and silicone resin plasters.


Tap water is suitable for preparing solutions of SILRES® BS 3003 for use as facade water repellent primer. We recommend an active substance content of 5-10% (dilute the product in the ratio 1:5 to 1:11), the exact figure depending on how absorbent the substrate is.

Apply the ready-to-use solution in the usual way:
flooding is the preferred way. Two "wet in wet" coats are needed to ensure complete coverage. Owing to the content of wetting agent in SILRES® BS 3003, reimpregnation at a later date does not present any difficulties.

If it starts raining, stop treatment and cover the freshly impregnated areas.


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.

The more dilute they are, the more they tend to cream. However, this phase separation may be reversed by brief stirring or agitation. This will restore it to a homogeneous emulsion, without loss of efficacy.

SILRES® BS 3003 contains minor amounts of a preservative that protects the emulsion against microbial contamination and fungal attack. The quality of the water used may make it necessary to add a biocide after dilution in principle, nearly any water-based preservative may be used.

Sales and support

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

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