(773) 588-0800

Restoration Supplier

Henry Frerk Sons is pleased to offer a full range of masonry restoration products, including:


  • The nation's broadest selection of historic lime mortars
  • Stone, brick, and terra cotta repair mortar, and we stock the 17 most common colors used in the Chicago area
  • Mineral coatings and stains for historic terra cotta, stone, and brick

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Restoration Products

Lime mortar is the material of choice for historic masonry buildings. Flexible and breathable, lime mortar accommodates freeze-thaw cycles and prevents damage to historic masonry units. It is breathable, vapor permeable and it wicks water out of masonry walls to protect brick and stone from water damage.


We offer a range of products and services to meet the needs of any project, from the smallest repair to complex restorations:

  • All of our historic mortars can be custom blended with specialty aggregates to match original mortar or restoration specifications.
  • We offer custom color matching to match the appearance of original mortar or to custom specifications.
  • Our “fast track” mortar matching enables you to choose from over 1,000 color formulations that we have on hand.
  • We provide mortar testing and analysis services and will match mortar to the original based on the results of laboratory testing.
  • For large jobs we can deliver mortar via silo system for greater efficiency and economy. We are the only supplier in the country to offer this service for historic mortars.
  • We ship nationwide.

Not sure where to start? Read Henry Frerk Son’s Lime Mortar Tips learn more about the different types of lime mortar and how to use them as well as our FAQs, which include the most common questions we get about lime mortar.



The Isaac Ritter House (c. 1875). Repointed in NHL 3.5 by A&M Masonry of Arlington, WI.
The Isaac Ritter House in Galena, IL (c. 1875). Repointed in NHL 3.5 by A&M Masonry of Arlington, WI.

Saint Astier® pure and natural hydraulic limes (NHL) have been in production for over 150 years. The characteristics of the raw materials are unique and consist of an undisturbed layer of calcareous rock infiltrated mainly by silica with only traces of other minerals. Millions of tons have been used successfully around the world in a wide range of climates.



St. Astier NHL 2.0 | Detailed Information Sheet | MSDS Sheet

55lb bag – 30 bags/skid. Skid discount available.

This is a pure and natural hydraulic lime, feebly hydraulic, used when elasticity, low strength or high vapor exchange are desirable. It is recommended for finishes and mortars for weak stones.

St. Astier NHL 3.5 | Detailed Information Sheet | MSDS Sheet

55lb bag – 30 bags/skid . Skid discount available.


This is a pure and natural hydraulic lime, moderately hydraulic, recommended when moderate strengths and better freeze-thaw resistance are required. It is recommended for base coats and stone work.

St. Astier NHL 5.0 | Detailed Information Sheet | MSDS Sheet

66lb bag – 30 bags/skid. Skid discount available.

This is a pure and natural hydraulic lime, eminently hydraulic, specified when strength and high freeze-thaw resistance are necessary. It is recommended for slabs and mortars for hard stones.

Niagara Pozzolan Hydraulic Lime (PHL)

This mortar is designed for historic restoration work and it duplicates the original lime mortar, plaster, and stuccos originally used on many historic buildings. It is also suitable for sustainable construction projects such as strawbale and hempcrete. PHL provides breathability, flexibility and durability which is necessary for both historic masonry restoration and sustainable construction.

 Niagra PHL contains absolutely no Portland Cement, which helps reduce potential damage in historic applications where it was not originally used. It also offers exceptional plasticity and workability, and as a lime based mortar this product provides excellent water vapor transference. This is especially important in non-Portland cement-based applications such as historic restoration or sustainable construction.

We offer Niagara® mature lime putty, which is a high-purity dolomitic lime putty product that is fully slaked and screened for immediate use.


Slaking quicklime for a long period of time enhances the workability and body of lime used in construction and restoration applications. This product is aged for a minimum of two months and has exceptional plasticity that is beneficial in dry mortars such as those used for tuckpointing. It is formulated to allow for volume proportioning equivalent to dry hydrate additions in compliance with ASTM C270.


Niagara® mature lime putty | Data Sheet

5 gal pail -24 pails/skid


Niagara® complies with ASTM C1489 (lime putty for structural purposes).

Jahn Repair Mortars by Cathedral Stone are single-component, cementitious, mineral based mortars, designed for the restoration of limestone, sandstone, granite, bluestone, marble, concrete, terra cotta, and brick.


A sandstone sill repair performed using Jahn M70 Sandstone
A sandstone sill repair performed using Jahn M70 Sandstone. Photo: Pawel Nawrocki, Carving in Stone

Unlike competitors’ products, Jahn has specifically formulated individual lines for each substrate. Their formulas are compatibility oriented ensure that the plaster substrate react to the environment in the same way as the Jahn addition. All Jahn repair mortars are vapor permeable and contain no latex or acrylic bonding agents or additives. This protects the substrate by allowing salts, water vapor, and liquid water to reach the surface, preventing failure due to salt expansion or freeze/thaw cycles. They are single component products that mix only with water, improving quality control and consistency of application. Additionally, Jahn repair mortars have strong bonding capabilities without relying on synthetic bonding agents, are factory controlled, can be colored upon request to match the existing masonry using standard or custom colors.

We have created the Chicago Color Collection, which contains 18 repair mortars selected just for Chicago. These colors match many of the most common stone, concrete and terra cotta materials found in Chicago and neighboring cities, and all colors are in stock at Henry Frerk Sons. This collection includes limestone, brownstone, concrete, terracotta, and marble mortars. We also offer in-house custom color matching and blending.


Certification Requirements


Only Certified Installers may purchase Jahn Repair Mortar. We offer certification to enable contractors, architects, and other professionals to obtain the required product certification. Our classes are two-day sessions and are discounted to $450.00 per person. Check the current schedule for upcoming classes.


Product Range


M70 Brownstone | M70 Datasheet | Safety Datasheet | M70 Specs


M70 Sandstone | M70 Datasheet | Safety Datasheet | M70 Specs


M70 Limestone |  M70 Datasheet | Safety Datasheet | M70 Specs


M90 Concrete and Precast | M90 Datasheet | Safety Datasheet | M90 Specs


M100 Terracotta & Brick | M100 Datasheet | Safety Datasheet | M100 Specs


M160 Bluestone |  M160 DatasheetSafety DatasheetM160 Specs


M160 Granite | M160 DatasheetSafety Datasheet |M160 Specs


M120 Marble |  M120 Datasheet | Safety Datasheet |M120 Specs


Helpful Links


Basic patching procedures (PDF) English | Spanish


Click here for a full listing of product data sheets, MSDS, and specifications.

Cathedral Stone Liquid Stain Kit is a two-part system, with a clear liquid fixative and pigment additives. Potassium silicate is a highly breathable (92%) treatment that also helps consolidate friable masonry.


Blend the pigments into the fixative to create a custom colored stain that can be layered to achieve increasingly intense color. This product is highly effective for matching new masonry to old, creating the effect of staining, and adjusting the color of patches and other infill. Potassium silicate stain is a proven material that has been used successfully for over a hundred years, and it is very long lasting and durable. For best results, the stain must be continually agitated during the application process so that the pigments are properly dispersed.


Liquid Stain Kit


Includes –


Liquid Silicate ( 1 qt. jar / 2.6 gal. pail)


Stain Kit-Liquid Pigments


Stain Kit-Pigment Powder

Terra Cotta Glaze (formerly MasonRE Terra Coat) is a non-yellowing, water-based, acrylic coating that highlights the natural color of masonry by providing a clear, semi-gloss sheen.


The treatment does not alter the natural texture of the surface, nor significantly affect the vapor transmission qualities of the substrate similar to that of glazed architectural tiles. Terra Cotta Glaze provides a durable finish to terra cotta and masonry surfaces with high abrasion, stain and chemical resistance. Its water base makes clean-up easy while still providing tenacious adhesion.


Terra Cotta Glaze | MSDS | Data Sheet | Specification Guidelines

Available in 1 gal or 5 gal.

Technical Data

Volume Solids: 28%
Flash Point:>212° F

A custom matched terra cotta glaze with mica.
A custom matched terra cotta glaze with mica. The original terra cotta is on the left.


We also offer the MasonRE Mineral Coating and MasonRE Terra Coating, which can be custom blended with colorants and additives such as mica to replicate the finish of historic terra cotta.


Using a combination of potassium and sol silicate, 100% inorganic, mineral pigments and fillers, KEIM offers superior bond strength while maintaining the highest levels of vapor permeability and color stability.


With his invention of silicate coating systems in 1878, Adolf Wilhelm Keim founded the company which today is known worldwide as the leading specialist in mineral architectural protection systems providing sustainable solutions. KEIM is a specialist among generalists: in their specific field of “mineral silicate architectural protection systems,” they supply highly developed comprehensive solutions for exterior and interior surfaces.

Innovation is also part of KEIM’s history. In 2002, what is now the third generation of mineral silicate paints, revolutionized exterior historic coatings by using a

An example of potassium silicate staining to match new brick with existing. The bottom brick is a sample of the existing brick that we were asked to match. We applied stain to the new unit (top brick) and achieved a match to the existing brick (bottom).
We applied stain to the new unit (top brick) and achieved a match to the existing brick (bottom).

sol-silicate binder. This combination of silica sol and potassium silicate not only provides bonding by silicification to mineral surfaces, but builds strong adhesive forces to previously painted, organic paints. This nanoparticle technology penetrates latex paint films to bond deep within the existing paint system and is the ideal repaint system when existing coatings cannot be removed.


All of our coatings and stains for historic masonry are breathable and vapor permeable. We offer a range of products from stains to coatings. Popular applications for these coatings include the use of custom tinted potassium silicate to match new masonry units to existing and “aging” new masonry and mortar to blend it with historic masonry.


Product Range | Technical Data Sheets | MSDS | Specs


Exterior Stains & Coatings

Interior Stains & Paints

Concrete Systems

Natural Stone & Masonry Systems

Stucco & Plaster Systems

Mineral-Art Paints, Stains, and Glazes


Helpful Links


KEIM Brochure


More about KEIM Products

Harsh chemical and abrasive cleaning methods are a leading cause of damage to historic masonry. We have compiled this list of recommended restoration cleaners that are specifically formulated for historic brick, stone, and terracotta.


Click here to see our complete list of restoration cleaners and sealers.