A Green Portland Cement Alternative, FAQ Friday with Randy Ruth

You might ask yourself… How is Natural Hydraulic Lime (NHL) a green building material? The simple answer would be that it releases about 80% less CO₂, pound for pound when compared to Ordinary Portland Cement (OPC) during the manufacturing process. But why is this so? Well that requires a bit of understanding on the manufacturing of the two very different products.

Both NHL and OPC are made from limestone, although not necessarily the same kinds of stone and are fired in a kiln. NHL is produced in Vertical shaft kilns, which is like a big chimney, with natural gas or clean coal at a low temperature. While OPC is burned in a rotary kiln fired at nearly 2,500 F. The amount fuel used to maintain such a high temperature is by far greater than the relatively low firing temperature of NHL.  Often hazardous waste is used as a fuel, which can emit toxins into the atmosphere. During either process CO₂ is driven off into the atmosphere. Even though NHL production drives off less CO₂, the benefits don’t stop there.

When the NHL is ready to be mixed as a mortar right out of the bag, it’s hungry. NHL wants the CO₂ that was pumped into the atmosphere back all for its self, in its natural process to turn back into a limestone. As different grades of NHL are produced their whiteness and density change. On a scale from lightest to heaviest and from whiteness to grayness, NHL 2 is Light and white while OPC in heavy and grey. Since mortar is mixed by volume in the field, less lime is used per pound to make up the same volume of mortar using OPC.

-LimeWorks.us (Linked-in : Blog : Facebook : Twitter)

Restoration of the Eldridge Street Synagogue in New York City with Ecologic® Mortar

In the heart of what is now Chinatown on the Lower East Side in Manhattan lives the Eldridge Street Synagogue. A very important Jewish Synagogue built in the late 1800s, it was the first synagogue to be built by the Eastern European Jews emigrating from Russia, Romania and Poland. The synagogue flourished for its first 50 years and was revered for its gorgeous vaulted ceilings and stained glass windows. But the membership began to dwindle following the great depression and was abandoned in the 1950s. Harsh city life ate away at the building, it became home to flocks of pigeons and other critters. Leaks developed and the stairs became unstable, the remaining members retreated to the basement where they remained for almost half a century.

The rescue effort of the Eldridge Street Synagogue began in the late 70s when volunteers and the Friends of the Eldridge Street Synagogue initiated efforts that led to an $18.5 million dollar repair campaign. This campaign included repointing work of the facade using Ecologic® Mortar from LimeWorks.us Additional repairs to the ceiling, wallpaper, paint and almost every aspect of the central room was restored returning it to its original glory. The final element was set during the fall of 2010, the stained-glass window commissioned by Kiki Smith and Deborah Gans is the only 21st century element inside the historic space.

More details of the Eldridge Street Synagogue restoration can be found in the latest issue of Traditional Building Magazine

-LimeWorks.us (Linked-in : Blog : Facebook : Twitter)

Facade after restoration, photo credit: Kate Milford

All Photos Copyright Sean K Maxwell

Lime Paint and Plastering System for Interior Application, FAQ Friday

Building on last week’s FAQ Friday, the use of lime paints doesn’t have to stop with use on the exterior of a building. Lime paints are great for use on interior walls by themselves or used as a pre-hydrated and dispersed pigmenting agent that can be mixed with Ecologic^® Mortar, NHL or a combination of the two when formulating your own colored plasters.

There are many benefits of using lime paint on internal walls but there sometimes needs to be some preparation involved to make sure that the lime paint or plaster will adhere to the substrate. Often times I hear that someone will want a colored plaster finish on their interior walls but they do not know if lime paint will adhere. The simplest way to check is to spritz some water on the wall. If there is no absorption of the water, the wall is either too smooth or not porous enough. We need some suction. One way to achieve this is to apply a base coat of Takcoat™.

Takcoat™.  was discussed in detail in a previous FAQ Friday. So to keep it short I will just say that it is a VOC free, transitional lime and sand prepared plaster material that can be applied to smooth painted or unpainted surfaces. Once Takcoat™. is cured then adequate suction and mechanical key is provided for Lime Paint and lime plaster to adhere to the wall surface. There are ranges of different lime finishes that can be applied to the wall ranging from a rough open pore surface texture to an incredibly smooth polished Venetian or Tadelakt finishing style. The finish is dependent on the client’s wishes and the skill level of the craftsperson.

In my opinion, craft skill level is fundamentally dependent on the tools a craftsperson has at their disposal. One important tool to have when formulating different plasters is pigmentation. The lime paints we sell at LimeWorks.us come in a variety of colors that can be used as integral pigments mixed into plaster formulations or on their own as a decorating top coat. Having a good pigmentation methodology gives a craftsperson more options during the planning stages of a project. A good pigmentation methodology also makes reproduction of the mockups on to the entire application easier once a decision has been made on a certain color since the consistency of our products makes this a smooth process.

Lime paint comes as a dry powder consisting of a high calcium lime paint base and dispersed pigments if the paint is a colored one. Dilution of the lime paint with water to make a quart, gallon or 5-gallon unit will further breakdown the pigment and further slake the hi-cal lime. When a known volume of paint has been made it can be used in Ecologic^® Mortar formulations or gauged into lime plaster for color. Here are a few examples…

Sample 1- lime paint lp-347 over Takcoat™

Sample 2- 1/2 bag NHL 2, 4.3 gallons LP-347, 1.09 gallons water over Takcoat™

Sample 3- one bag Ecologic® Mortar Fine with 1gallon LP-347 over Takcoat™

Sample 4- one bag Ecologic® Mortar with 1quart LP-347 over Takcoat™

When a specific color is desired but not represented by our stock lime paint color options then we can provide custom colored blends for all sorts of various applications. Seen in the photos below Thuillier Plastering of New Hampshire used a custom Ecologic^® Mortar Fine that incorporated additional NHL 2 and pigments to achieve a Tadelakt finish. The authentic formulation was then polished with rubbing stones and the olive oil soap we sell, following an ancient Moroccan tradition.

So whether you know what style of plaster finish you want to achieve or you would rather let your imagination run wild and experiment, just contact us and we will be able to help you develop your plaster system to ensure a successful project.

-LimeWorks.us (Linked-in : Blog : Facebook : Twitter)

FAQ Friday, with Randy Ruth

This is the first in a series of blog entries that will feature mason, Randy Ruth. Randy is the lab technician at LimeWorks and receives lots of questions on masonry and the use of our materials. We will feature some of these questions each Friday in our FAQ Friday blog entry. First question…

• Q: I have an old stone basement foundation (house was built in 1900) and need to “re-point” or fill in holes in the basement walls.  Would your Ecologic mortar work? I am not sure that lime based mortar was used originally; would this still be OK or how can I tell if lime was used?
• A: “cement” was not produced in the united states until 1870 in Coplay, PA, only up until around 1910 was Portland cement starting to find its place in society as a masonry binder. Prior to 1910, most mortars used were based on either lime putty, Natural hydraulic quicklime or natural cement. Regardless of what the exact mix design was used to build your basement foundation, Ecologic® Mortar would most likely be suitable for repointing your old stone basement foundation walls as it would be sympathetic to the adjacent mortar mix by maintaining good vapor permeability. An easy way to determine if you have a lime based mortar, especially in stone construction, is to break a piece from the wall in visually inspect for any white nodules or specks. The white nodules are an indicator of what is called a “hot lime” mix and commonly found in stonework . Any presence of those nodules or specks suggests a high lime content mortar, and should thus be repaired with a comparable material.