Water Repellent, Breathable Protective Coating for Concrete and Masonry


Si-Rex03 Silicone Resin Emulsion Paint (SREP) is a state-of-the-art industrial exterior wall and façade coating specifically designed for use on concrete and masonry substrates.

The advanced silicone resin binder system delivers a sophisticated architectural matte finish with proven protection and performance benefits.

Si-Rex03 is a water-based, one part system that provides easy application, an outstanding look and finish plus convenience of a long pot life.


Si-Rex03 not only protects the substrate with excellent water repellency – it also allows the substrate to breathe thus minimizing the potential for peeling and flaking from entrapped moisture.


The silicone in Si-Rex03 reacts to form a 3-dimensional “quartz-like structure” of alternating silicone and oxygen atoms; a durable structure unaffected by UV light and weathering conditions. Water repellent groups line the pores of the paint and stop the ingress of liquid water but allow vapor to outgas. This unique structure is the key to the performance of Si-Rex03 and its ability to protect the concrete or masonry substrate.


Si-Rex03 is available in many colors including a wide color range of neutral and earthy tones that complement concrete and masonry substrates. Only high quality, inorganic oxide pigments that do not degrade with exposure to UV light and weathering are used to deliver fade resistant, dynamic colors that last.


All colorants are VOC (Volatile Organic Compounds) and APE (Alkyl Phenol Ethoxylate) free making them compliant with latest requirements and anticipated regulations.

Refer Product Data Sheet (TDS) for use and application guidelines.


Approved and/or specified as a preferred protective coating system by numerous state transportation and other state/county/city authorities plus chartered organizations for use on concrete infrastructure and facilities.

Prestressed Beam crop

Evaluated and approved for use to help limit detrimental effects caused by future expansion in Concrete Structures due to ASR (alkali-silica reaction) and/or DEF (delayed ettringite formation) activity. Results in helping stabilize structural integrity and thus extend service life.



Designed specifically for use with Si-Rex03, the use on bare substrates of penetrating primer Si-Prime adds to the performance, durability and substrate protection traits of the Silicone Resin Emulsion Paint (SREP) coating system.


Klaas Coatings (North America) LLC
PO Box 25122
Dallas, TX 75225-1122

T: 866-317-3633 (toll free)
F: 214-363-8422

E: info@klaascoatings-northamerica.com

Markets We Supply

Transportation Infrastructure
Parking Structures
Office Buildings
Commercial and Retail
Warehousing and Distribution
Precast Concrete Fabricators
Historic Structures
Sport Complexes
Condominiums and Multi-Family
Tourism Infrastructure
Schools and Colleges

Technical Support

Looking for Application Guidelines?
Needing specification reference?



All orders supplied ex-factory – products not available through retailers.

Some regional building product distributors may carry, or order in, product as needed.

Product packaging
(packed volume by weight):

Si-Rex03 - 5 Gallon Pail or 55 Gallon Drum
Si-Prime - 5 Gallon Pail

Si-Rex03 orders are custom batch tinted at factory. Batch tinting ensures exact same color pail-to-pail. Minimum Order Quantities (MOQ) apply; contact for details.