Chicago masonry waterproofing guide
Choosing a masonry water repellent depends on the material, its porosity, previous coatings, exposure, and the source of the moisture. This guide compares common commercial products used on brick and block, with practical notes for Chicago's wind-driven rain and freeze-thaw conditions.
Important disclaimer
Product properties below come from manufacturer technical data and the comparison material cited at the end of this page. Results vary with substrate condition, preparation, coverage rate, weather, and application. A water repellent does not repair cracks, failed mortar joints, flashing, coping, roof defects, or below-grade water entry. This guide is educational and is not a performance warranty.
Masonry waterproofing
Use the short comparison first, then follow the evidence links for the product-specific test details and source attribution.
Star's standard
formerly Enviroseal PBT
formerly Double 7
Product details
Star Tuckpointing uses Protectosil CHEM-TRETE PB 100 exclusively for penetrating masonry water-repellent applications. The manufacturer's current technical data lists pure silane, 100% active content by weight, and no solvent. It describes the product as a clear, penetrating, breathable water repellent for exterior above-grade concrete masonry units, brick masonry, and most natural stone.
We use one standard product so our crews can focus on consistent preparation and application. Product selection is only one part of the work: the masonry must be inspected, necessary repairs completed, and a test area evaluated before treatment.
formerly Enviroseal PBT
BASF / Master Builders Solutions
MasterProtect H 185 is a water-based silane-siloxane blend formerly sold as Enviroseal PBT. It is described for lightweight, split-face, and standard CMU, with suitability depending on the substrate.
formerly Double 7
BASF / Master Builders Solutions
MasterProtect H 177 is a water-based silane-siloxane sealer formerly sold as Double 7. It is intended for dense vertical brick and masonry, so the substrate and exposure still matter.
Professional Products of Kansas, Inc.
Professional PWS-15 is a 15% RTV silicone, solvent-based water repellent for porous vertical masonry. Professional Products of Kansas, Inc. describes the product as breathable, UV-resistant, and able to bridge hairline cracks; those are manufacturer descriptions rather than numbered durability results.
PROSOCO
PROSOCO Blok-Guard & Graffiti Control WB 6 is a 6% silicone emulsion carried in water for specialty graffiti control on porous masonry. It is a surface treatment, not a direct substitute for a penetrating silane, and reapplication may be needed where cleaned.
Measured performance
These are product-specific indicators from the cited technical data sheets; they are not guaranteed service-life figures.
Penetrating repellents last by reacting below the masonry surface, where the treatment is less exposed to surface wear. Silane molecules are smaller and can penetrate more deeply, but industry guidance indicates that meaningful penetration depends on a high active-solids level. Siloxanes are commonly used on porous brick and stone; silane-siloxane blends combine penetration with surface water beading.
Industry literature gives broad context, not a promise for any product here. One bridge-and-masonry presentation describes silane service life of roughly 6-12 years and retreatment intervals of 6-10 years, while a bridge-core study found residual protection after 20 years. Those findings depend on substrate, exposure, preparation, application, and test method and must not be shown as a CHEM-TRETE PB 100 lifespan.
Context sources: NAHB/Euclid CP-19; ACA/CoatingsTech; Aktas et al. (2021); LHTAC; and Christodoulou et al. (2013).
FAQ
We use Protectosil CHEM-TRETE PB 100 exclusively for penetrating masonry water-repellent applications. Before recommending treatment, we check whether the moisture source is the masonry surface or a repair issue such as open joints, cracks, flashing, or coping.
The manufacturer describes it as clear and says it will not adversely affect the surface appearance of a suitable substrate. Because masonry varies, a test area should be completed before full application.
Yes. The manufacturer describes the treatment as breathable and reports that natural moisture-vapor transmission is not affected.
No. A penetrating water repellent can reduce water entering through a porous masonry surface, but it does not repair cracks, failed mortar joints, defective flashing, coping, roof details, or below-grade water entry.
Yes. The manufacturer states that repointing, patching, caulking, and concrete repair must be completed and cured before application. The masonry also needs appropriate cleaning and dry weather.
Next step
Not sure whether water is entering through porous brick, failed mortar joints, flashing, coping, or another detail? Request a masonry moisture evaluation. We will inspect the substrate and explain whether repairs, a penetrating water repellent, or both make sense.
References
Product properties and laboratory results are linked to the technical data and screening documents used for this comparison. Industry sources provide context only; they are not product-specific service-life promises.
