Limelight on New York City

New York City surpassed Philadelphia in 1790 as the largest city in the United States. Throughout the 19th and 20th centuries immigration and modern developments changed many facets of the people, transportation and infrastructure. But what still remains in the city that never sleeps are gorgeous relics of the past, being preserved for generations to come. A team from LimeWorks.us recently visited the Big Apple to take look at a few places which have been repaired in-kind with historically appropriate materials.

The New York Life Building was completed in 1928 at a cost of $21 Million. It’s currently undergoing a repair campaign using Lithomex for stone repairs and patchwork.

The Irish Hunger Memorial stands as a tribute and reminder of the Great Irish Famine and the tragedy of world hunger. Stones were donated from each county of Ireland and even an entire cottage was transported and reassembled on site at Battery Park in Manhattan. Historically accurate lime mortar was used in the construction of this memorial which ensures that it will remain standing tall.

The Eldridge Street Synagogue is an incredibly gorgeous testament to the architecture and influence that once spanned across the Lower East Side from the Eastern European Jewish community. This was the first Synagogue constructed by the Eastern European Jews emigrating from Russian, Romania, and Poland. It was built in the late 1800s and flourished into the mid 20th Century. As the neighborhood changed and new immigrants arrived, membership dropped and the synagogue was left virtually abandoned through the rest of the 20th 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 historically accurate Natural Hydraulic Lime 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 ofTraditional Building Magazine

We also visited the Cathedral of Saint John the Divine and the Ephesus Seventh Day Adventist Church in Harlem. Both have used in-kind repair materials from LimeWorks.us. By using breathable masonry repair materials, all of these historic structures will surely stand as testaments to the rich history of the Big Apple for generations to come.

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

All Photos Copyright: Sean K Maxwell

Reconstitution of Historic Lime Mortar and Renders FAQ Friday

Today Randy has another great post about an interesting technique for historic preservation. This is something Andy deGruchy will be speaking about at the upcoming Greater Philadelphia Building & Facility Maintenance Show November 9th. Signup to participate in this free conference and visit the LimeWorks.us Group exhibit booth.

Q: I want to restore my old stone house and have heard there are ways to reuse the mortar already in my building during the repointing process. Can you explain how to do that and what are the positive and negative impacts?

A: Reusing old historic mortar is possible in more ways than one. The first methodology would be to leave sound mortar alone and keep using it for as long as possible, only doing “patch” pointing in areas that need to be fixed. In cases where a building owner desires to repoint the whole building you can follow the backyard guidelines below.

Of course if one were to follow these guidelines then there must be a conservation mindset in the back of their head. Knowing this, a mortar analysis would be highly recommended to help conclude an appropriate mortar mix design.

Reconstitution of historic lime mortar and renders

The purpose of this procedure is to separate the lime from the historic aggregates to reproduce a mortar joint or render while retaining as much of a buildings historic fabric as possible without the use of acids.

Beginning with the removal of any loose, cracked or friable render or mortar in the gentlest means possible put debris aside.

Using a concrete barrel mixer place all saved debris in the mixer with large heavy stones or steel balls, about the size of a bowling ball. Make sure that the chosen crushing medium is harder than the debris to minimize contamination of the crushed aggregate by foreign matter. The mixer should be filled only to the point where the crushing medium will effectively fall from the apex of the mixing rotation and crush the debris to what would be the consistency of a pre-blended dry bagged mortar. This process should take anywhere from 20 – 60 minutes depending the quantity of the material loaded in the mixer (less is faster) and the desired fineness of the aggregates. Be sure not to over mix. Over mixing will result in the deformation of the aggregate.

Once the debris has been crushed to the desired particle size, place in 5-gallon pails or wheelbarrow for the separation process.

Place the end of a hose running water beneath the crushed aggregate. While the container is filling with water be sure to slowly agitate the wet aggregate mix with a hoe or trowel. Be sure to allow the fine lime particles to spill over the sides of container to be discarded. Make sure that the larger aggregate stays settled to bottom of the container for reclamation. This process should take approximately 20-60 minutes depending on amount of crushed debris and its binder to aggregate ratio. The process is completed when the water runs fairly clear and the remaining fines in the mixture can be easily made into a ball that resembles saturated beach sand.

Upon completion of filtering the lime from the aggregate allow to dry in the open air and strong sun by spreading it out on as thinly as possible over a tarp.

Once the aggregates are dry, the large particles of broken stone, any other foreign matter and large unbroken debris can be dry screened out using the desired sieve size. Typically anything retained on a #4 sieve can be discarded.

Now that the aggregate is dried and sieved, new mortar formulations can commence. Depending on the amount of work to be done with the reclaimed aggregate and the amount that was actually reclaimed, determination of how much other similar aggregate is to be gauged in to the new repointing or rendering mix.

To learn more about this technique please visit us at the Greater Philadelphia Building & Facilities Maintenance Show November 9-10 in Oaks PA.

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

Stucco Over Historic Stone Buildings, FAQ Friday

Q: Why are beautiful stone farmhouses and other historic stone buildings covered with stucco? Is it for insulation? If the stucco over stone is an original and historically accurate detail, is it then OK to remove it to expose the stone and leave it that way? Will this enhance or deflate the value of the building in its authenticity?

A: Traditionally the only exposed stone is one with a gauged mortar joint. “Free stonework” are irregular pieces of stone shaped to fit with large, squared corner stones with alternating lengths used as borders. Ashlar work is varying sizes of cut blocks of stone that are laid in uniform coursing. You will sometimes see semi-coursed stonework on the front of a building and haphazard stone joinery on the sides and the back of the building. If the stone was shaped with tools used by masons it most likely was meant to be seen. You will often see remnants of the original external plaster or whitewash in the pours of the stone of the building which has already had the stucco removed to tip you off that the building was originally covered or coated and not exposed.

Fieldstones are stones picked up off the field when settling a property and preparing the ground for farming. They are laid up in “rubble work.” Some masons pronounce it “roobil” work. I think they are just repeating the accent of the old-timers. Rubble is junk. Fieldstone is just junk stone It is not dressed up in any way.

But the question remains, “Why did they cover the stone with exterior plaster?” Well, when you don’t gauge the joints and keep them tight the surface exposure to the elements is increased and accelerated the erosion of the pointing mortar. This may quickly deteriorated the bedding mortar and the integrity of the wall. It will at least aid in the transmission of water into the building. So, the same soft, punky mortar that was used for bedding was also used for exterior plaster, (stucco), and finished off with a shelter coat of whitewash. Whitewash is pure calcium carbonate lime and water. It was used as a waterproofer and protecting coat for both beauty and function. Whitewash could be thought of as a coating like an eggshell. It is soft, breathable and will protect the otherwise frail stucco render. Today the appearance of rubblework exposed is thought of as a thing of beauty. Historically fine stonework was squared and formal with straight, true and gauged joinery as the sign of high-end work. Really, it still is throughout the world, but “beauty is in the eye of the beholder.” If historic stone buildings where not plastered, (receiving an external stucco render), but instead received the inverted “v” joint to deflect the downward and angled drive of the rain, they usually were whitewashed right over top of the stone and joint in rubble work. When you don’t see the whitewash over the stone anymore it is because the acidity of a constant rainwater bath has loosened it and it has come off and was not renewed. More often than not it remains under the porch of houses and forebay areas of barns where it has been protected. Look closely in the pours of the stonework on the sides of the building and under the eaves or behind pent roof to see it remnants of the stucco or whitewash has remained. Another tell-tale sign that the building was originally stuccoed over the stone is that the widow trim remains proud to the stonework. If the trim comes out past the stonework at a thickness of 1-1’1/2″ past the stone, then that is indicative that the stone was covered with stucco the meet the outer edge of the wood trim.

The only insulation gained by exterior plaster is that of slowing a driving wind. Overall masonry is a poor insulator. 1940 and newer stucco may have had perlite incorporated into the mix to add an insulatve element.

To correctly restore something would mean to put it back to its original design. For correct architectural restoration of a stucco over stone building means that the plaster should remain and be finished as it was originally. However, many people with unsound exterior plaster, which has lost its bond to the substrate or has cracks throughout it or has paint that is flaking, consider the removal of the offending stucco and coatings without replacing it but rather exposing, cleaning and repointing the stone. It is an option that will help mitigate the water infiltration problem. It is an option for overcoming the eyesore of flaking paint. It even increases the value of the building in many cases more than what the cost was to expose and repoint the stone. But my advise is to “just say no” when you have a formal exterior such as a building with a mansard roof. An exposed stone building which has been repointed and does not have the stucco or whitewash renewed should be reserved for a simple country farmhouse, outbuilding or barn in my opinion. It may effect the value of the property in a negative way by removing historic details. A local historic appropriateness review board may not allow these modifications and a historical society may frown upon changing the unique and appropriate details originally found at the historic structure.