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Proper Ratio of Lime to Sand

Proper Ratio of Lime to Sand

We get asked the question often “What ratio of lime to sand should I use?”  Our answer is “We don’t know until we know what the void space of your sand is,”   There are thousands and thousands of sands across the USA, and within those myriad of sands, there are literally countless ways that manufactures sieve, wash and process the sand you purchase at your local masonry or building supply company.

One of our sayings here at Lancaster Lime Works is “Sand is not Sand is not Sand.”  Even the mason’s sand that is provided in huge piles at your local masonry supply company will vary from load to load.  It is of utmost importance to test the sand that will be used in our lime putty for the following: Void Space and Particle Size/Shape/Distribution.

Our lime putty is the best available.  However, if too much or too little lime is added to your sand, product failure will be the result. Therefore we spend just as much time explaining and teaching about sand as we do about installation of lime based mortars

The Basics are Simple:2015-03-20-07-18-47
The void space between the sand is similar to the space between beach balls in a display bin at Walmart.  In between these beach balls there is room for smaller soccer balls, then in between the soccer balls there is room for baseballs, then in between the base balls there is room for marbles, then in between the marbles there is still space for even smaller particles such as dust and yet there is still empty space between all these balls. This is called the “void space.”   Sand has the same.

The void space within the sand must be filled with the lime putty.  Too much lime will push the sand particles apart; not enough lime will leave “holes” in the mortar, and both scenarios will leave you with a weak mortar, stucco or plaster.

Lime Mortars gain the majority of their strength from the sand and rely on the sharp pieces of sand making contact with each other and compacting firmly together. The Lime develops a crystal structure that binds the already sharp, compacted and interlocking sand particles together.

Portland Cement based mortars are comparable to a two part epoxy glue, they gain the majority of their strength from the binder which is the Portland.  The Portland basically “glues” the sand together and negates the necessity for grading and evaluating sand that is needed for Lime Mortars. Lime mortar is a cushion between the building stones or bricks, Portland Cement mortar is a glue that holds the stones or bricks together.

The Correct Ratio:

The ratio of lime to sand is always variable.  Specifications calling for such ratios of 1:2, 1:3 or 1:1 lime to sand are misleading, confusing and could quite possibly be wrong.  The lime:sand ratio will absolutely vary from sand to sand and from load to load. The correct ratio of lime:sand is determined by discovering the void space within the sand chosen for the project.  The void space within the sand must be filled with the lime putty – too much lime will push the sand particles apart, not enough lime will leave “holes” in the mortar and both scenarios will leave you with a weak mortar or plaster.

The results of having the correct ratio are fun to watch and are observed when mixing batches of lime mortar.  If the ratio of lime to sand is 1:3 (one lime:three sand), that will mean dumping three evenly filled buckets of sand into the mixer and one bucket of putty for a total of four buckets added.  If not too much lime has been added, only three buckets of lime mortar will be removed from the mixer because the putty just fills the space between the sand.

We believe that all masons should have the skills to determine the void space within the sand they are using and be able to prove and explain to the architects and engineers that they are using the correct amount of lime for the sand chosen for the project.

The testing method of finding the void space between the particles of sand is relatively simple yet very very important to prevent mortar failure and obtain a strong lime mortar. (more about how to do this in the next blog)

Our goal and Lancaster Lime Works is to provide the training and resources to mason’s and architects to match and install all historic mortars.  Please contact us with questions.

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Renovations of Three Downtown Springfield buildings Reveal Glimpses of Past – News – The State Journal-Register – Springfield, IL

Items from the past are always fun to find when you’re restoring Old Historic Buildings.

It’s nice to see more interest in restoring our past for the future going on all across the US.def04199858b46db922dd91d702986d3_B1NpPM
The work also has turned up small reminders here and there of office work before the age of computers and high-speed Internet. Someone working in the Booth building, for instance, apparently had a fondness for Bubble Up soda. A metal spittoon and a Tuxedo Tobacco tin preceded smoking bans. No modern office was complete without Purity Typewriter Oil. The product said so right on the label.”It will not gum or get rancid.

Heavy brown fabric — similar in touch to burlap — helped keep elevators quiet. Levison & Blythe Manufacturing Co. of St. Louis produced the typewriter cleaning oil. Mail tubes ran between floors for interoffice correspondence. Patches of white mosaic tile can still be found. Removal of a wall revealed skylights that apparently had been obscured for decades.

“We’re just kind of collecting it all,” Lawrence said. “We’ll probably put them on display somewhere in the building, maybe in the lobby. It helps show the history of the buildings.”

Lawrence, who heads Siciliano Inc. of Springfield, estimated that it would take another two years to complete restoration of all three buildings.

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The Ferguson and Booth buildings were both built in the early 1900s, according to a history compiled by Lawrence. Both are eight stories high. The three-story Bateman-Kennedy Building in between dates to the 1800s. Early work is concentrating on the westernmost Booth Building, where plans include 21 upper-level apartments and lower-level commercial space.

Lawrence, who declined to estimate the cost of the project, said his goal is to open apartments in the Booth Building in early 2016, followed by completion of the Bateman-Kennedy and Ferguson buildings.

The long-term plan is for a single entrance through the Bateman-Kennedy Building to the upper levels of all three buildings. Three to four apartments also are planned in the Bateman-Kennedy Building. Cafe Brio restaurant will remain on the ground floor of the Ferguson Building, which will be remodeled for office and conference space. Lawrence said he envisions a fitness center and an upper-story restaurant among the possibilities.

via Renovations of three downtown Springfield buildings reveal glimpses of past – News – The State Journal-Register – Springfield, IL

 

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Classic Red Stone 1900’s Historic Building Fighting for Restoration!

Kozy Building Passing 11th Hour For Restoration | FOX 21 News, KQDS-DT

Let’s see What Happens here in September 2015? This is occuring all over the US.

 

DULUTH, Minn. – 28 June 2015

It’s been nearly five years since the troubled Kozy building went up in flames in Duluth. And today, it remains arguably the biggest eyesore in downtown Duluth.

But a businessman behind the restoration plans tells FOX 21’s Dan Hanger he’s got one more solid shot at millions in housing tax credits to turn the property around before the weather takes its final beating on the building or the city of Duluth heads in for demolition.

“There’s a little bit of displacement in the arch and we’re seeing that in a few areas. That wasn’t there last year, so that tells us the clock is running,” said Mike Conlan, former Duluth director of planning and development, and current business partner with Eric Ringsred who owns the building.

“The seriousness is if we’re not successful this year, we’re probably going to throw in the towel and say, ok, we’ve been trying this for three years,” Conlan said.

But Conlan believes his recent application for $7 million in state Housing Tax Credits seems promising this time around after being denied last year.

“The engineering study is done. The architectural work is done. Appraisals have been done. Market studies — all of that. It’s a complete package,” Conlan said.

In the meantime, while Mayor Don Ness wants to see the historic building finally restored, he also says the demolition process by the city is very real and only the fault of the property owner.

“There should have been investment made years ago. First of all, the building should have been insured so when it went up in flames, they would have had the dollars to reinvest and fix the building, but it wasn’t insured,” Ness explained.

While Conlan doesn’t own the building, he remains hopeful the state will pull through with the $7 million in tax credits before the clock strikes midnight.

“It’s all in before the state. And again, they tell us it’s a competitive proposal, they like it, but of course it’s statewide competition,” Conlan said.

“They need to step up in a major way if this building is going to be saved,” Ness said.

via Kozy Building Passing 11th Hour For Restoration | FOX 21 News, KQDS-DT | Welcome to FOX 21 Online

 

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A Few Advantages of Lime Based Mortar

A Few Advantages of Lime Based Mortar

The core concern in masonry preservation is a commitment to using lime based mortar for all historic structures. Lime based mortar has many advantages over Portland cement. Here is a short list of just a few advantages:

 

Lime based mortar is more flexible and less brittle.
If there is building movement, lime mortar will eventually re-seal the cracks in the mortar. Having a softer mortar means soft bricks and stones won’t be forced to break. The mortar is the “sacrificial component” of any masonry wall. With Portland, the mortar is so hard that it chisels off the faces of the bricks with even the slightest building movement and all buildings move.

 

Lime based mortar is breathable.
This means that moisture that gets in the wall (from damp conditions inside or outside) will escape rapidly. Portland cement seals moisture into a wall, causing mold problems inside, deterioration of wood, and deterioration of the bricks or stones themselves.Lime based mortar still sheds water from rain just as well as Portland cement.

 

Lime mortar lasts longer.
Lime will last longer than Portland cement. Lime mortar that is made from 98% pure calcium will last 100 years minimum. Portland cement mortar lasts about 50 years, and sometimes cracking and deterioration is visible within 10 years. Portland cement degrades from the inside out because of impurities like aluminum silicates. These impurities cause it to get hard fast, but also cause it to deteriorate fast.

 

Because lime based mortar is softer, it can be removed easily, without damaging the bricks or stones. Portland mortar is so hard that it is very difficult to replace without breaking or de-facing the bricks or stones, even if it is badly deteriorated.

 

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General Project Conditions for Using Lime Mortar

General Project Conditions for Using Lime Mortar

1. Bedding and lime pointing mortar should be placed only if air and masonry temperatures are between 40°F (4°C) and 80°F (27°C), and the air is relatively calm. Conditions must remain so for at least 48 hours after completion of work. If conditions are not within these parameters, Contractor shall take all necessary measures to ensure that the manufacturer recommended protection and curing requirements are met, including as necessary, dampening of burlap, polyethylene sheeting, wind barriers, and other protection as needed.

 

2. The wall must be thoroughly whetted down at least 24 hours before work is begun. The wall must again be whetted down at the beginning of the day then be monitored thru-out the day. If the wall drys out it will suck the moisture from the lime and the lime mortar will not reach it’s compressive strength.

 

3. Contractor must be aware that working conditions change thru the day. In the morning hours the temps will be cooler and the surface will not have direct sun. In the afternoon the mason must provide proper shade from direct sunlight or the lime will dry out to quickly. All masons on the project must constantly monitor the pre-wetting conditions and apply more water as needed to keep the wall at a proper moisture content.

 

4. Contractor shall not start work until joint faces and solid bedding have been prepared as approved.

 

5. Contractor shall not allow direct weather related water against mortar until it has reached its full cure.

These general guidelines for working with lime mortar are not complete and should only be used as a starting point. Using Lime Mortar requires extensive training. Contact Lancaster Lime Works for more information on how to use Lime Mortar and to purchase it.

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Brick and Mortar Basics

Brick and Mortar Basics

The following provides an overview of the characteristics of brick and mortar, and how they sustain unnecessary damage through improper maintenance. This is provided to assist in understanding the masonry sections of this report. A more thorough comparison of Portland mortar and hydraulic lime mortar will be found in some of our other blog posts.

 

Bricks that were used in the construction of the original older buildings were fired at lower temperatures than modern brick. They do have a hard exterior, but are still much more porous (absorbent to moisture) than modern bricks. If the harder face of the brick is removed by sandblasting, the much more porous and fragile interior of the brick is exposed to the weather. Sandblasting was widely accepted in the past as a way to clean dirty, painted, or stuccoed brick. It is now widely known to significantly weaken brick’s resistance to damage from weather.

 

The original brick and mortar building walls were laid with hydraulic lime mortar, which has been in use for around 7,500 years. It is made by burning limestone, and it gets hard by going through a chemical reaction with water. It is very different from the Portland cement mortars used over the last 100 years. Portland cement is much harder, less flexible, and is completely non-porous. Portland cement mortars are now known to threaten the longevity of brick and stone walls, and can greatly accelerate damage to soft brick.

Moisture from the weather, both humidity in the air and precipitation, penetrates bricks and stones in a wall because they are naturally porous. This moisture in the bricks can cause rapid damage to the bricks if it cannot escape quickly, especially in freezing weather. Hydraulic lime mortar allows moisture to escape very quickly out of a wall. Portland cement traps moisture in the wall. Moisture that is trapped in a brick wall causes the brick faces to break off, leaving a rough, ugly, fragile exterior. It also causes moisture problems on the interior, such as plaster decay, stains, and wood rot.

Brick and Mortar walls that are constructed of older, softer brick should be repointed with hydraulic lime mortar, never Portland cement. Walls that have been repointed with Portland-based mortar should be repointed with hydraulic lime mortar. Brick faces that have been severely deteriorated can either be repaired or replaced. Replacement of the bricks can be done by finding new bricks that match, or by removing and turning around the original bricks. Damaged bricks can be repaired by using Lithomex, a flexible, porous, lime-based material that is applied in lifts to the face of the damaged brick bringing it back to its original shape, size and color. It bonds with the damaged face of the brick, and becomes a permanent repair.

Old brick and mortar with damaged bricks can also be removed from the wall using special tools. Sometimes the damaged and spalling bricks can be removed, turned around and reinstalled. Others will be so badly deteriorated that they will need to be replaced entirely.

The method of removal for existing Portland-based mortar is extremely important. Using a grinder will create a lot of dust, and the spinning diamond blade very easily causes irreparable damage to the face of the old brick. We suggest using a power tool called Arbortech, along with a high quality vacuum system. It has two vibrating blades that act like scissors, cutting into the Portland-based mortar and greatly minimizing potential damage.

Contact Lancaster Lime Works

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What Makes a Great Lime for True Lime Mortars

What Makes a Great Lime for True Lime Mortars?

Higher calcium content leads to quicker carbonation and a more durable mortar. Magnesium and other impurities either don’t react or react slowly with CO2. But is high-calcium lime enough to make a good lime-only mortar? No. Food-grade calcium hydrate is pure, but does not have high surface area for CO2 reactivity. A calcium hydroxide slurry for deacidification is more likely to have high-surface area, but may not be high-calcium. Limes manufactured for Portland cement need to be “dead burned” (sintered) so the lime and Portland (hydraulic) reactions don’t compete.

 

A “soft-burned” lime (maintained at 900°C) has a porous “coral-like” surface that is derived from firing the lime optimally to drive off CO2 (see below). Lime for Portland-based masonry mixes continues to be fired beyond this stage until the pores close up again. This material adds plasticity to stiff and brittle Portland, but would not provide porosity or reactivity for lime-only mortar.

 

When a soft, self-healing, porous, and breathable surface is desired, then a high-calcium, “softburned” lime is ideal. Only a purpose-made architectural lime putty will have high surface area (greater than 30 m2/g) and porosity that comes from “soft burning” and the chemical purity of a consistently high calcium content. Together these characteristics ensure all of the lime is acting as a binder (cementing the aggregate particles). Architectural lime putty makes great mortar without Portland cement or pozzolans. And only lime mortars are consistently compatible with historic lime-only mortars that rarely exceed 200 p.s.i. and allow full water and vapor movement to the exterior of a wall. Remember, the role of mortar is to cushion the masonry units and accommodate movement while eliminating point-loading. Lime mortars meet this requirement fully.

The lime cycle is a closed loop. Calcium Carbonate [CaCO3, i.e. limestone, oyster shell] is fired to drive off the CO2, making Calcium Oxide [CaO, quicklime]. When water is introduced during the volatile process called slaking, calcium hydroxide is formed [Ca(OH)2]. Lime putty is calcium hydroxide. As water leaves the lime, carbon dioxide from the air begins to take its place, once again reacting with the lime to create Calcium Carbonate again. There is an increase in mass associated with carbonation that counteracts shrinkage from water loss.What if we slake calcium oxide ourselves? Good quality control in manufacturing Sample A produced an optimum lime putty. The same oxide slaked by hand without precise control of water feed rate and temperature created the inferior putties, C and D. Reactivity is created through careful control in firing and slaking. Small particles and high surface area create longer decantation times (the time necessary for a particle to settle out). Viscosity is related to surface area and plasticity. Greater plasticity and water-holding capacity mean better working properties and contribute to low shrinkage from water loss.

True lime mortars set (carbonate or “cure”) by reacting with atmospheric CO2, creating a sort of man-made limestone. Hydraulic mortars (Portland cement, bagged mortar mixes, and hydraulic limes and cements) set by reacting with water. The firing of all mortar constituents drives off CO2, but the reabsorption of this CO2 by lime mortars makes it a more environmentally-responsible building choice. Lime mortars are also less fuel intensive to produce than Portland-based mortars.

Blog post attributed to www.preservationscience.com