Let’s Talk Sand

Our Ecologic™ Mortar uses a sharp well graded proprietary blend, so it’s not just ANY Sand!

The dictionary definition of Sand: weathered particles of rocks, usually high in silica, smaller than gravels and larger than silts, typically between about 0.06 mm to 5 mm. The particles are hard and will not crumble. Sand is used as an aggregate in mortars, plasters and renders as well as a component in concretes. The properties of sand used in a mix have a major effect on its workability, final strength and durability.

The types of sand normally used in building are:

  1. Sharp sand: consists of predominantly sharp angular grains. Clean well graded sharp sand for mortar, render and plaster is selected as the best for the strength and durability it imparts to the finished work. Workability is improved by mixing with fat lime as the binder and allowing this to stand as coarse stuff (not possible with OPC as a binder on its own).
  2. Coarse sand: A sand which is composed of predominantly large and medium sized grains. The higher the proportion of large grains, then the coarser the sand. Coarse sand is used for external renders and mortars to improve durability. Very coarse sands usually require a lime binder, blending with other sands or the addition of a plasticizer to assist workability. Sharp coarse sand is the most durable but the least workable, although suitable for roughcast.
  3. Soft sand: A sand which is composed of predominantly small and rounded grains. It often has a set content, the proportion of which is variable. It feels soft in the hand when squeezed. The smallest rounded particles assist workability but can give rise to cracking and failure in the finished work.
  4. Well-graded sand: A sand with an approximately even particle size distribution. As the smaller particles may fit in between the larger particles, this even distribution reduces the proportion of voids to solids and thus is less demanding on the binder than poorly-graded sand.
  5. Blended sand: A blend of sands of different grain sizes and sharpness to achieve a good particle size distribution. This provides a balance between durability and workability. Used mostly in connection with plaster for backing coats and pointing mortar when the quality of available sand needs to be improved. Sand may be blended by sieving it to adjust the particle size proportions, or by using sands from different sources.

Taken from Ecole d’Avignon/Re’seau Art Nouveau

Click here to read more about the ‘right’ sand for your mortar project.

Sand

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Restoring Mt. Vernon’s Upper Garden Wall

Mt Vernon's Flower Garden

by Debra Grube and Samantha Horvath

LimeWorks.us is providing a custom blend of our Ecologic™ Mortar for the restoration of Mt. Vernon’s Upper Garden Wall.

Mt. Vernon was built in 1735 by George Washington’s father, Augustine, and George acquired Mount Vernon in 1754.  It began as a one and one-half story farmhouse, and over the next 45 years the building was slowly enlarged to create the wonderful 21-room residence we see today.  Washington personally supervised each renovation, selecting architectural features that expressed his growing status as a Virginian gentleman planter and ultimately as the first President of the United States.

The gardens that surround the mansion, however, were just as important as the living quarters considering they sustained the food supply of the family and all the visitors that flocked to George Washington’s home every year.  Even when the Washingtons were not present at the mansion, Martha Washington made sure the gardens were well tended, to be sure of the supply and abundance of fruits and vegetables upon their return.  The upper garden was transformed into a pleasure garden, occupied by a myriad of beautiful flowers surrounding the remaining vegetable beds. Washington procured the pleasure garden, along with a green house, as an alluring keynote for his guests to admire the beauty and fragrances provided by his lush gardens.

In the attached video you will catch glimpses of the upper garden wall, which is currently being restored using LimeWorks.us’ Ecologic™ Mortar manufactured using St. Astier’s NHL 2 and a custom blend of aggregates and pigments to simulate the coloration of the historic garden wall. Although you will not see the actual mortar in use, these videos below share more about the Upper and Lower Gardens.

The Beautiful Upper Garden at Mt Vernon

The Lower Garden at Mt. Vernon

The information shared here has been taken from the Mt Vernon Website.  Further reading and in depth history and facts of George Washington’s Mt. Vernon, can be found at their site.

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Masonry Pore Structures

Lime putty for mortar has been in known use for over 6000 years. Modern Portland cement, lime and sand mortars have dominated for less than 100 years with many known failures. Here are what some modern scientific investigations have found about what worked so well about lime mortars and why so many modern mortars may not be appropriate for historic restoration. This information is offered so that you can make an informed choice on which binder to use for your projects.

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1 LIME PUTTY TO 3 PARTS OF SHARP SAND

This cross section cut away of a traditional lime putty mortar demonstrates via the blue dyed epoxy resin, which fills the open pore structure, that historic mortar based solely on lime and sand have a tremendously high and desirable liquid and vapor permeability.

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1 NATURAL HYDRAULIC LIME (3.5) TO 3 SHARP SAND

Note the high porosity of this mortar formulation. The wall can breathe by allowing moisture to enter and exit the system, encourage the crystalline bridging phenomenon (also known as the autogenous or self-healing properties of lime mortar) by dissolving free lime in the mix and re-depositing it to close larger fissures. Excess moisture then quickly evaporates back into the atmosphere. The open pore structure allows the carbon dioxide, needed for carbonation during curing, to be delivered deeper into the mortar.

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1 NATURAL HYDRAULIC LIME (5) TO 3 SHARP SAND

Note that the pore structure is still open but finer and more dense than the Natural hydraulic lime 3.5. This mortar is suitable for copings, parging and pointing in extremely wet conditions including sea driven rain with high salt content.

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1 PORTLAND CEMENT TO 3 PARTS SHARP SAND

Note the dense fabric and the greatly reduced porosity, with only the presence of shrinkage cracks. The shrinkage cracks are a portal for moisture to get into the absorptive bedding mortar (usually of lime and sand.) Normally, the sun will draw moisture back out of a lime joint. However, Portland cement based mortars trap moisture within the wall system because their dense pore structure does not always allow it to escape through evaporation. The saturated wall of trapped moisture can lead to moisture being driven much further into the building when heat inside draws moisture through the wall, or trapped moisture evaporates out through the softer historic brick or stone accelerating its deterioration.

Petrographic thin section images courtesy of William Revie of The Construction Materials Consulting Group; Stirling, Scotland

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Lime as a Green Build Material

Here’s How St. Astier Natural Hydraulic Lime (NHL) Plays An Important Role In Construction As A Green Build Material.

St. Astier is a 100% natural product and does not contain any additives. It is one of the greenest materials used in construction. This is due to its purity, its calcium carbonate composition, its longevity and potential for allowing the materials to be reused or recycled, and the result of a low energy production process.

The amount of energy used at the production stage is a fraction of what is needed to produce cement. Consequently, the release of CO2 into the atmosphere is reduced considerably. Furthermore, contrary to cement, NHL reabsorbs most of the CO2 during the curing process, while cement reabsorbs none.

NHL has received the LABELVERT EXCELL, or “Green Label”, in France. This label guarantees the total absence of contaminants and any risk of pollution. It also authorizes the use of this product in chemically sensitive areas such as living spaces, wine cellars, etc. Other attributes listed below, prove over and over NHL outperforms modern day Portland cement.

  • The absence of detrimental chemicals like tri-calcium aluminate, potassium and sodium oxides (which are ever-present in cement), protect NHL mortars from chemical reactions such as sulfate or alkali attacks.
  • Very rapid evaporation of moisture from NHL mortars ensures that the drying cycle is faster than cement mortars and subsequently the healing requirements are lower.
    Material used in construction with NHL may be reused or recycled. In addition, the NHL mortar itself may be recycled in a number of ways, such as an aggregate for new lime mortars, fertilizer (NHL is calcium carbonate), or it can be used for water purification to adjust pH levels.
  • Breathability, elasticity, plasticity, gradual development of strength, low shrinkage, longevity, CO2 absorption, self-healing through the presence of free (or available) lime in crystalline bridging to close minor fissures, are all highly desirable. These traits, with sustainability and “greenness”, are only some of the qualities of St. Astier Natural Hydraulic Lime.
  • The change-of-use of older buildings through adaptation or preservation and restoration maximizes the need for the environmental recovery of materials. It is essential to ensure the long term survival of these structures with compatible materials. Some buildings have been in use for centuries; there is no logical reason that this cannot continue. Preservation, adaptation and restoration can have significant environmental advantages over new construction. Aside from the environmental impact, there is the aesthetic value in preservation. Natural Hydraulic Limes have a significant part to play in the process.
  • Material longevity is unsurpassed when applied and maintained correctly and its life will span over several generations. The manufacturer’s warranty subsequently extends for 50 years.

 

CO2 Emissions Chart
CO2 Emissions Chart

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Restoring St. Patrick’s Cathedral

An Undertaking of Passion and Love

LimeWorks.us is a big part of helping to restore a prominent landmark in New York City, St. Patrick’s Cathedral. The Cathedral was completed in 1878. Then in 1888 spires were added. The picture below is taken from near the top of one of one of the spires.

From the Spires of St Patrick's Cathedral
From the Spires of St Patrick’s Cathedral

The Cathedral is undergoing an extensive restoration project.

Restoration Announcement and to learn more St. Patrick’s Cathedral click here:

Workers are in the process of fully restoring the St. Patrick’s Cathedral. This work includes cleaning and repointing all exterior stonework and repairing the stained glass windows. LimeWorks.us is supplying all of the lime mortar for the full repointing campaign using our Ecologic Mortar (SCG) F; that is made of St Astier NHL and sand. This work is necessary to ensure that this beautiful New York City landmark endures for many future generations!

Thanks to the gracious invite by Deerpath Construction, the contractor doing the work, who extended to those of our staff in attendance at APT NYC, we received a special tour up on the
scaffolding. It was an awesome view and wonderful to see our Ecologic™ Mortar based made with St. Astier NHL being used to restore this famous and very important building of the NY skyline.

For additional information, or to purchase:

Ecologic™ Mortar

St. Astier NHL

 

Click here to see a short video on St. Patrick’s Transformation

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Limelight on the Restoration of the Rotunda at the University of Virginia

The University of Virginia is the only US university with a World Heritage designation, it’s conservation is of the utmost importance and is currently undergoing the largest restoration campaign in decades. Matt Wolf and his team from Centennial Preservation are currently working on the repointing and window repairs for the Rotunda at Thomas Jefferson’s Academical Village.

Mortar studies showed the original mortar was made with hydraulic lime which led to the specification of a customized LimeWorks.us Ecologic™ Mortar for the repointing campaign. Ecologic™ Mortar is an environmentally friendly, breathable, Natural Hydraulic Lime based mortar available in 8 stock and countless custom colors.

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Chemistry of Lime Mortar – Neighborhood Preservation in Philadelphia

19th Street Baptist Church
19th Street Baptist Church

The Chemical Heritage Foundation released an episode of their award winning podcast Distillations.  In this episode, Randy Ruth, formerly of LimeWorks.us, discusses the chemistry behind lime mortar, historic masonry buildings and the ongoing efforts to preserve one of the finest works of notable Philadelphia architect, Frank Furness. The 19th Street Baptist Church located in South Philadelphia has been in a state of disrepair for decades.  This episode sheds light on the chemistry behind its construction and the ongoing preparation to save it.

Inside the 19th Street Baptist Church
Inside the 19th Street Baptist Church

 

 

Photos © Sean K Maxwell
Other stories related to the 19th Street Baptist Church:

Yes We Can Save The 19th Street Baptist Church

Progress at 19th Street Baptist

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Linked-in : Blog : Store : How2

 

Audio Transcript Excerpts:

Randy Ruth, at the time, was the lab tech at LimeWorks.us. He bridged the gap between architects, conservators and masonry practitioners on what types of building materials to use in reconstruction and restoration of masonry projects throughout the country.

“Randy and his colleagues at LimeWorks.us based in Quakertown, Pennsylvania were brought in to try and save the 19th Street Baptist Church

We took a look at at the types of mortars that were there and by knowing that the building was built in 1874 we could gauge what those original binders were without even necessarily doing an analysis. Architects, engineers and of course masons would use the local available materials which were at the 19th Street Baptist Church primarily lime based binders.

Lime is a very general term for inorganic materials that contain calcium and it’s been use in concrete and building materials since the Roman Empire. It’s derived from limestone and other rocks that are primarily made of calcium carbonate.

Basically lime is that calcium carbonate stone and it’s put into a kiln with fuel. These kilns would then be fired up to 900 degrees Celsius or slightly above and then the resulting product is a limestone that loses about a third of its weight because it’s driving off carbon dioxide so that calcium carbonate is now becoming calcium oxide.

This is all part of what’s called the Lime Cycle. Calcium carbonate is heated to produce calcium oxide and then it’s combined with water to form calcium hydroxide. Different amounts of water is added to form different consistencies.

That process is called slaking, if just a small amount of water is added it’s going to turn into a powder. If a little bit more water is added it’s still calcium hydroxide but it’s in the form of a putty.

Once the lime is in this putty form it’s spread over bricks and stones and hardens into a solid bond.

That limestone then stays malleable and flexible in a wall system in comparison to more modern materials.

Modern materials like cement. Portland cement is the most common type of cement used around the world. It’s made of primarily alite or tricalcium silicate, a more rigid and less permeable material than lime.

You’re walking down the sidewalk and wondering why are they sectioned off in four food squares or six foot squares and that’s because Portland cement is very brittle and we have to tell it where to crack and where to go versus the lime buildings like the 19th Street Baptist Church. There are no control joints and things were able to move freely and accommodate small bits of movement because lime unlike Portland Cement has the ability to heal itself, something called autogenous healing.

This autogenous healing is part of why the 19th Street Baptist Church is still standing today but the original lime mortar is all but dissolved now and that’s why the building is crumbling.

Lime mortars as they age and as they wear, they’re meant to be replaced so there’s always a maintenance issue associated with them. I hope that there is a lot of architectural salvage that can occur to pay homage to the traditional materials that were originally by Frank Furness and his architectural team.

In essence they should be able to replenish the lime mortar in the structure, but after so many years of neglect it’s getting late in the game.”

Photos © Sean K Maxwell

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Repair Campaign at the Rotunda, University of Virginia Restores with Lime

uva-lawn-tim-jarrett

We’re so proud to be part of an incredible restoration campaign currently taking place at the University of Virginia. The Rotunda is the focal point of Thomas Jefferson’s Academical Village at UVA and we have the pleasure of supplying our Ecologic™ Mortar for the repointing campaign. Below is an excerpt from the university’s website explaining the repairs that are currently taking place, also take a minute watch the brief video.

Preserving the Heart of the Grounds

The capitals atop the Rotunda’s columns were shrouded in protective netting after it was discovered that they were crumbling from age and a variety of other issues.

Thomas Jefferson intended the Rotunda, which he called a “temple of knowledge,” to be the centerpiece of the Academical Village; it housed the heart of the University operations—the library and classrooms. The Rotunda and associated grounds are now in critical need of extensive repairs. The renovation, which began in May 2012, will span several years.

What specific repairs and renovations are being done?

The Rotunda renovation includes extensive infrastructure upgrades and exterior repairs. The initial phases are addressing conditions that threaten the building’s integrity and include significant roof repairs, column capital restoration, masonry repairs, and window restoration. Panels in the Dome Room will be replaced with a better acoustical control system; lightning protection will be greatly improved; and a new elevator installed.

Later phases of the project will entail improvements to the Rotunda’s interior infrastructure and restoration of the surrounding landscape. The building’s aging infrastructure, including plumbing, electrical, audio/visual, heating/air conditioning, and fire protection, will be upgraded. Portions of the building may be adapted to allow for classroom use. The current total estimated cost is $50.6 million.

Photo by Tim Jarrett

Read more about the restoration efforts here.

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Preserving America’s Historic Barns – A Conversation With Historian Jeff Marshall

Screenshot 2015-08-04 09.58.49 (2)Watch our Limelight on America’s historic barns. Historian Jeff Marshall discusses his appreciation and understanding of barns, barn builders and their lasting legacy.

BARN AGAIN!!  Preserving and Repurposing the Past

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Limelight on Historic Brownstone Restoration – Alfred’s Victorian

Alfred’s Victorian Restoration Story –  with Andy deGruchy

Alfred's Victorian Staff
Alfred’s Victorian Staff

 

This beautiful late 19th century Hummelstown brownstone was recently restored by deGruchy Masonry Restoration, the Technical Install/Training Team of LimeWorks.us. Using historically appropriate, breathable Natural Hydraulic Lime based materials for repointing the brickwork and repairing the brownstone, this iconic building is now put into an excellent state of conservation. It remains a testament to excellent stewardship of our built heritage thanks to the owner, and lifelong resident of Middletown, PA, Robin Pellegrini.

Taking an architectural conservator’s approach, the team of masons repaired the broken and missing pieces of historic sandstone and lime mortar with environmentally friendly Ecologic® Mortar and Lithomex Brick and Stone repair material. The team retained as much of the historic fabric as possible by repairing what could be salvaged with these specialty materials. These materials allow the building envelope to process water out naturally through the lime and sandstone because of their effective liquid/vapor transfer properties over any patch material based on Portland cement.

Please take a look at our other videos for the full extent of this remarkable restoration:

True Sustainable Development in Historic Restoration  – Alfred’s Victorian –  Randy Ruth

Restoring Historic Alfred’s Victorian Brownstone  –  Randy Ruth

Natural Hydraulic Lime Mortars for Historic Preservation and Their Impact on the Environment –  Randy Ruth

 

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