Architectural Support Services, Lime Mortar Matching, Mortar Testing, Stone Repair Mortars, On-Site Contractor Training, Workshops in Historic Masonry Skills.
The U.S. Heritage Group provides everything necessary to develop a total historic mortar solution: architectural support services, scientific mortar testing, custom mortar matching, pre-blended lime mortars, stone repair mortars, specialized contractor on-site training, and quality control services. Many historic buildings are damaged by repair mortars that do not contain lime. USHG assists in educating architects, mason contractors, building owners as well as government agencies in the benefits of using traditional materials to preserve and restore America's masonry built heritage. Historically accurate mortar should always incorporate the original ingredients which, before 1931, almost always included lime putty.
Our Specialties: Mortar Testing, Historic Mortar Analysis, Mortar Matching, Masonry Skills Training Workshops, Lime Mortar, Lime Putty, Lime Paint, Harling, Stucco, Masonry Restoration, Working Advisor Service, Architecture/Design Support and Consultation.
At right heritage masonry skills are authoritatively demonstrated at a US Heritage workshop.
We recommend that U.S. Heritage Group be commissioned to inspect the building and advise on specifications for repairs in conjunction with the original material specifications, proposed project specifications and our mortar analysis. Our consulting team consists of architects, conservators, heritage masons and project managers. Team members have worked on some of the most prestigious historic masonry structures in the world including the U.S. Capitol, Washington D.C. Union Station, Indianapolis: Parliament Hill, Ottawa, Canada; Stonehenge and Windsor Castle, England and the Statue of Liberty. These professionals have published over 50 articles and books on the different aspects of historic masonry. Our consulting services include: evaluation of original mortars; identifying and offering solutions for moisture problems; locating sources for stone and brick replacement; stone and brick patching alternatives; and stucco, limewash and lime paint options. Our international experience, coupled with our knowledge of traditional building technology, allows us to provide solutions to your problems while maintaining the integrity of your historic structure.
Mortar Testing. As you know, many challenges exist in matching historic mortars. Actually these variables can be isolated down to three critical areas: 1) material ingredients (which would include identification of original components), 2) installation (which would include proper mixing and site preparation), and 3) curing conditions and tooling. Locating a testing lab that offers mortar analysis is typically not a problem. The biggest challenge exists in formulating a successful replication mortar mix based on the data gathered from an analysis. Proper installation with the understanding of appropriate curing conditions only comes after a successful replacement mix has been identified. Our mortar analysis will serve as a guide for specification of replacement materials, with appropriate interpretation and adjustment to take into consideration current site conditions, present condition of masonry, and the function of the new mortar and degree of weather exposure. The mortar testing we will perform involves using petrographic analysis followed by laboratory procedures. The procedures include microscopic examination of disintegrated material and hydrochloric acid dissolution of binder and aggregate. The largest constituent of mortar is sand. While our mortar analysis attempts to identify the original binder (amount of lime and cement) it also places a strong emphasizes on establishing a satisfactory sand match. U.S. Heritage Group has established a national sand library in Chicago that catalogs aggregates according to color, shape and gradation characteristics. Sand profiles are placed on a grain distribution chart that provides a basis for determining an appropriate color and gradation match. This library is geographically filed which assists us in matching mortars in different cities. Once the analysis is completed and the data is stored, the results are used to re-construct the original material. The aggregate void ratios are calculated in preparing the new mortar formulation, which guarantees a balance between lime and sand. A traditional Mortar Mill Mixer designed and built from 1879 specifications is used for lime putty mixes. This ensures that all sand particles are evenly coated with lime. Laboratory cured samples of the replacement mortar are sent to the site for visual approval by the architect and planning team. In addition, a ready-mixed mortar sample is also sent to the site. This ready-mixed sample represents the proposed mortar formulation and is designed to be mixed with water for the test mock-up panel. It is necessary that a qualified craft person who understands the curing and application details of traditional lime mortars install the sample. The sample should be allowed to cure in the wall for a minimum of seven but preferably fourteen days before final color match is approved. Once the mortar match is confirmed the custom mortar is produced and packaged in 3.5-gallon containers then shipped directly to the site ready to use. Mortar Production U.S. Heritage Group can assist in eliminating jobsite mistakes in mortar preparation and mixing by offering ready-mixed mortars. We can bring together all the important information from the site evaluations, original specifications and the mortar analysis to produce a custom mortar unique to the project. Once the mortar is successfully matched, the information can be used at any time in the future to reproduce the original formulation at no additional cost of testing throughout the life of the building. Note: This mortar match and related test data becomes a permanent record at the U.S. Heritage Group laboratories.
Training. U.S. Heritage Group works closely with government agencies in other countries offering valuable information regarding preservation trends and traditional material research, along with insight into old world craftsmanship. A strong emphasis is placed upon helping our trades people understand and appreciate traditional materials, their properties and performance characteristics. U.S. Heritage Group offers two-day workshops that provide valuable information and proven field techniques to historic preservation specialists, masons, building owners, architects, consultants and engineers who are involved in selecting, designing, installing, restoring or maintaining historic masonry buildings. These two-day courses provide participants with hands-on experience in the preparation and application of historic lime mortars. If necessary, U.S. Heritage Group is also able to provide quality control assistance as "working" advisors and train the masons at the site. Working Advisor Services U.S. Heritage Group can be hired directly by the owner, or the owner's representative or the general contractor, as working advisors to train the mason contractor on the site in the proper repointing, finishing and curing techniques of traditional historic lime mortars. Our heritage masons can teach the very techniques that were most likely used when your historic property was originally constructed. Training the lead foreman while installing the mock up samples of the proposed mortar match is the best way to help establish workmanship standards. The mock up samples are then used for quality control purposes to evaluate the workmanship of the mason contractor as the project progresses. We also provide project manager advisory services, to support your project management team in the unique requirements of historic masonry restoration. These services can provide a flexible means to meet our client's need for direct technical assistance.
Architecture/Design Support. US Heritage Group is dedicated to maintaining the special aesthetic characteristics of historic masonry buildings. Traditionally, lime based stucco, plaster, or harling was applied to the exterior (and interior) of a masonry building. These materials were considered a sacrificial element, meant to bear the brunt of wind, rain and snow. A lime paint or Iimewash was then used as a decorative finish, but also served the purpose of protecting the masonry. The unique characteristic of these materials was their ability to allow the wall to "breath". US Heritage Group is pleased to offer a complete line of these traditional materials, tailored to fit your project. The colors of these materials are much softer and more transparent than modern coatings, with a wide variety of subtle shades and tones available. We are able to provide materials from our stock color chart, or can custom match to your requirements. As with our mortars, simply supply us with an example of the color you would like, and we will send a match for your approval. We also can provide technical support in the application of these traditional finishes.
U. S. Heritage Group, Inc.
3516 N. Kostner Ave
Chicago, IL 60641
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