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  Glacier Blue® Architectural Topics & News
     Monthly Educational Newsletter
December 2007
In This Issue
Contents:
 
Educational Topic of the Month: Damp Proofing Your Stone Surface
 
 
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salem NYDevonian Stone of New York, Inc. is a full-service stone mining and fabrication company that specializes in "high-end" cut-to-size Glacier Blue® Devonian Sandstone products. This stone has been used in residential, institutional and commercial projects around the country.  
Pioneer Building Materials Offers Practical Knowledge for Architects and Contractors
Pioneer Building Materials in New Hyde Park, NY is not only a source of supplies for the construction industry, but of information as well. They have a technical staff that is available to sort out the details that go into both small and large projects, and offer information on how to execute them. They will discuss your requirements and share their practical knowledge on product application. Aside from offering a full range of building materials such as mason materials, hardscape materials, veneering stone, ready-mix concrete, millwork and winter deicer supplier, their goal is to create a professional atmosphere in which architects, engineers, contractors and homeowners are provided with the material, support and advice necessary to successfully meet the demands of their project.
 
Pioneer Building Materials is a family owned business that has been at the same location for over 54 years.

For more information visit: http://www.stixnstones.com.
Educational Topic of the Month: Damp Proofing Your Stone Surface
 
damp proofing
Damp proofing your stone surface can mean the difference between the stone application lasting only months or many, many years. And what, exactly, is damp proofing? Damp proofing is a way to treat stone tiles so that moisture, or rising damp, cannot pass through the stone from the substrate underneath and cause efflorescence and other damage. It helps to prevent the passage of water in the absence of hydrostatic pressure, and although it is not necessarily waterproof, it is still breathable, allowing water vapor (but not water) to escape.

Rising damp is the movement of moisture upward through porous building materials, such as stone. Brick, stone and mortar are porous and allow damp from the ground to rise by capillary action, carrying with it ground salts including chlorides and nitrates. If the moisture evaporates through the stone, these salts will be left behind and form deposits on or within the evaporative surface. If evaporation is restricted to localized areas, then salt deposits form thick crystalline deposits with the appearance of small flowers, called efflorescence. When evaporation occurs within the stone, salts can be deposited within the pores. The expanding salt crystals in these locations may result in fractures forming in the stone and spalling of the surface.

Chris Hansen of Pioneer Building Materials in New Hyde Park, NY spoke with us about the importance of damp proofing a stone surface.  He explains, "We learned about damp proofing about ten or fifteen years ago when thousands of square feet of limestone we sold to a contractor became discolored and the customer had to rip it all out. The stone turned all different kinds of greenish brown colors and the contractor thought we sold him bad stone."

"Limestone is a grayish color and usually comes from Indiana. When we thought the problem was the stone, we called the quarry and they asked us if the contractor damp proofed the stone before he installed it. He proceeded to then put us in touch with the Indiana Limestone Institute (www.iliai.com) and they gave us tons of information about how to damp proof on a vertical surface, how to damp proof on a horizontal application, every which way to install stone. Jim Owens, the head of the institute, travels around the country and does seminars about how to damp proof."

"So with that project, it turns out there was nothing was wrong with the stone, it was the means by which it was installed. You have the concrete slab underneath the stone, and then underneath that there is the soil. If the soil is wet and the sun comes out, the sun draws the moisture into the atmosphere. Now it's drawing it through the concrete slab, through the stone and discoloring the stone itself. Installers should really take those precautions to damp proof the stone to prevent the solids from coming up through the stone and causing discoloration."

"The theory is the same for other stones too, whether it's sandstone, bluestone, granite, or limestone. Let's say we pour a slab of cement and we're going to put any kind of stone on top of it, you're going to cement that stone down to that slab. Now that slab is usually poured over dirt or aggregate, the slab is still curing, it's still hydrating, it's still green and it still has to cure. Once I put the stone on top of that concrete that's still curing, the water is hydrating or evaporating, migrating out of the slab and up through the stone, because the sun is heating it up and drawing it out. What happens once that moisture passes through the stone, the moisture is going to go back into the air as a vapor and leave impurities on the surface of the material or within the stone, thus creating efflorescence, which is white. Like on a brick house, you'll see white around the brick. That is from the mortar in the joint curing, the water is being evaporated because the sun is heating it up and drawing the water out of the mortar, thus leaving the solids behind, the salt and the calcium and any other organic material, which then you have to acid wash to get rid of the efflorescence."

Efflorescence is a crystalline deposit, usually white, that may develop on the surface of the masonry construction shortly after installation. There are combinations of factors that contribute to the cause of efflorescence. First there must be soluble salts in the masonry, which in hydrated Portland cement is inevitable due to the chemical reaction between cement or lime and water. This chemical reaction produces calcium hydroxide when brought to the surface by water and combines with carbon dioxide in the air to form calcium carbonate, which then appears as a whitish deposit. Second, there must be moisture to pick up the soluble salts and carry them to the surface. If the area is exposed to the outside environment then it is safe to say there will be moisture present. Third, evaporation or hydrostatic pressure must cause the solution to move. As the moisture passes through the masonry, it collects the soluble salts and brings them to the surface. The moisture evaporates leaving behind salts or a whitish deposit. Usually efflorescence is more common in the winter when there is a slower rate of evaporation. The moisture stays within the masonry structure longer, collecting the soluble salts. When the moisture finally comes to the surface, it carries additional soluble salts resulting in greater whitish deposits.

The way damp proofing is applied depends on the type of application where it is needed. There are three types of damp proofing remedies. The first is a silane diffusion which utilizes a concentrated thixotropic silane or silicone cream to form a barrier against rising damp. As the cream slowly diffuses, it releases a silane vapour which reacts with the silica in the masonry to form a water repellent resin. The second is a siliconate transfusion which is a gravity fed system with no wastage via hidden voids. The gravity-fed transfusion units allow a slow, even distribution of the siliconate fluid into the wall and to form a damp proof barrier, but unlike pressure injection, there is no wastage via hidden fissures or voids. The third is siliconate injection, which is sometimes recommended, primarily for single brick walls. The fluid is injected into the wall with single lance under low pressure to form the barrier against rising damp.

For the purposes of installing stone tiles on a concrete slab, Hansen explains, "We were told through the Indiana Limestone Institute to damp proof the bottom edge or the bottom surface of the stone and also the edges that are within the mortar joint, the side edges. So every unexposed edge would be waterproofed or damp proofed. The impurities would not come out of the stone if it was damp proofed, nothing can pull that through because you protected it, even on the edges, the sides that have the mortar joint. Every edge is protected except the top exposed surface. The damp proofing that is applied is like a cementitious based paint, like a real thick slurry. It has a sandy texture to it and it keeps the moisture out, but it's still breathable."

Although damp proofing is essential in many cases to help ensure the longevity of your stone surface, it also helps to have proper ground drainage that is adequately leveled. An effective detail to use around a building is a ventilated and drained 'dry area' around the foot of the wall. These are commonly covered with stone slabs in order to prevent debris from accumulating in the dry area and to minimize maintenance. By paying proper attention to design details such as water stops, flashing, weep holes and copings, you can provide for proper drainage which, along with damp proofing, will help to ensure that your masonry is as weather resistant as possible, making it last for many years.
Architects - Share Your Expertise!
We recently asked architects what topics they would like to see covered in our newsletter and were pleasantly surprised with the overwhelmingly positive response we received! 
 
We are also now featuring interviews with architects who would like to share their experience and insight on a topic of their choice. If you have an idea you would like to contribute or a topic you would like us to research, please let us know by sending an email to info@devonianstone.com. If chosen, your firm will also be featured as our architectural firm of the month.
We hope you enjoyed our informative monthly e-newsletter. For questions, comments or more information, please e-mail or call us today.
 
Sincerely,
 
Liz Benton, Editor 
Glacier Blue® Architectural Topics & News
Devonian Stone of New York, Inc.
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