Masonry Magazine August 1995 Page. 18
An additional step that should be considered if you are going over existing concrete is to acid wash the concrete with a 20% muriatic acid solution and thoroughly rinse with water. This wash process will ensure that the porosity of the concrete has been exposed for good bonding.
Adhesives work on the premise that they adhere to the porosity of the materials that they are bonding, and it's very important to ensure that both your paving stones and concrete are clean and dry.
Be sure to use a paver adhesive that has been specifically formulated and engineered for the specialized task of facing or veneering paving stones to concrete substrates. Preferred choice paver bond is an adhesive synthetic rubber resin that has the consistency of a hard rubber tire, but when given a blow or subjected to the flex of a paving stone, it responds with the appropriate flexibility. This characteristic allows the adhesive paver bond to perform well in freeze/thaw situations.
When preparing for your adhesive installation you should examine each paving stone for any possible defect and measure each stone to ensure that it's the proper thickness. ASTM standards allow for slight variances in thickness which are forgiven in a sand bedding course, but on a solid substrate they must be as closely consistent as possible.
When applying the paver bond adhesive to the paving stone it is recommended that a total peripheral 1/4" bead be applied to the bottom of the stone within 1" of all edges.
This practice ensures that the paving stone is properly bonded to the substrate, and also creates a barrier which precludes water entry beneath the paving stone.
The installer will develop his own style in terms of layout and design, but if he keeps in mind that he should install with the vertical riser paving stone first and then go over the top edge with the tread paving stone, he will ensure a safe and solid step. This tread is actually the soldier course of the installation and works both for the tread and boarder.
When looking for methods of holding that riser paving stone in place, we find that small 4" pieces of banding folded in half and placed under the stone work well while the adhesive sets.
In addition to "face" work applications, paver bond adhesive is used extensively in the retaining wall industry. Segmental retaining wall systems have varying degrees of adhesive requirements which are directly dependent on their specific system design. The vast majority of wall systems have a cap or coping unit which tops the wall as well as creates a tread when the wall system is utilized as a step unit. In these applications, paver bond adhesive is used to permanently secure the copings in place to prevent unauthorized removal and to create a safe installation.
While some wall systems have a definitive 90 degree corner design which utilizes gravity and design to create interlock, there are others that do not. They put that design feature directly on the shoulders of the contractor.
The contractor is many cases has to cut individual retaining wall stones to create the corner design and then is able to use paver bond adhesive to secure his work and ensure permanence.
Adhesive work can be very rewarding once the contractor has a full understanding of proper methodology. Following the proper guidelines will ensure the basis for a good installation.
Mason Named
Worker of Year
TODD BJORK, above, was named the winner of Dickies Workwear's American Worker of the Year award. Bjork's entry was selected from among thousands of entries from all across the country. Entrants were asked to write fifty words or less about how their nominee best represents the phrase "An honest day's work." Bjork, 28, a stonemason from Cable, Wisconsin, was nominated by his wife who wrote, "My husband has labored as a mason for six years to put me through college. My man comes home weather-beaten and covered from head to toe in mortar dust. And to him I give all my love." Bjork received a full-sized Chevrolet pickup truck and a trip to the Grand Ole Opry in Nashville for an awards celebration.
SHARING THE
IS CARING
SALVATIONS
ARMY
PARTITION WALLS
Continued from Page 16
nance and beauty.
The systems briefly covered in this digest clearly demonstrate the versatility of masonry. Not only is it a favorite for exterior usage, but now it is clearly an interior choice for those who value quality coupled with economy and speed of construction. It is our intention that the graphs and diagrams that have been provided will simplify choosing engineered brick and concrete masonry systems for your upcoming projects.
CHARLES W. OSTRANDER, Executive Director of the Illinois Masonry Institute, is a founding member of The Masonry Society, a past Director of the Structural Engineers Association and a member of ASCE. He's also an engineering consultant for programs developed by the Masonry Advisory Council and the Illinois-Indiana Masonry Advisory Council. Ostrander has served as a guest lecturer at the University of Notre Dame Architectural School, the University of Illinois Architectural School at the Urbana and Chicago Campuses, the Illinois Institute of Technology Architectural School, Northwestern University Engineering College, and Valparaiso University Engineering College. He's a graduate of the University of Illinois with a BS degree in Civil Engineering and a registered Professional Engineer in Illinois.
18 MASONRY-JULY/AUGUST, 1995