Total Repointing, FAQ Friday

Q: What is the correct method for total repointing?

A: Correct total repointing requires removing the joint to a depth of approximately 2-1/2 times its width and then using a compatible mortar in relation to the final p.s.i. and both the liquid and vapor transmission rate as that of the remaining joint and brick. High lime content pointing mortar is compatible with
the soft and absorptive nature of historic brick which rely on their “fired skin” to protect themselves and the building from rain intrusion. If high concentrations of Portland cement were in the repointing mortar instead of lime, when moisture in the brick were to expand and contract during freeze/thaw cycles, often the unyielding mortar forces the softer face of the brick to exfoliate thus leaving a vulnerable unburned “salmon” center of the brick exposed to the elements.

Soda Blasting a Cushwa Brick Fireplace

deGruchy Masonry used Armex baking soda today to remove soot and smoke from a Cushwa brick interior fireplace. This house addition, which is an extension to a historic stone schoolhouse, (ca 1840), was a complete loss in a fire that happened this year. The owner who has lived there 45 years is rebuilding! She’s “old school” and won’t let the loss get in her way. She plans to rise up from the ashes and save the old schoolhouse and her home.

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.

Limelight on Stonemason and Sculptor Steve Snyder of Bucks County

“Using appropriate mortar is something I’ve been interested in as long as I’ve been in masonry and it’s something you never stop learning about and trying to get right.Using Natural Hydraulic Lime has been a big part of making mortar that’s better for the buildings we’re working on…”

-Steve Snyder

Take a Look: Our first “Spark Segment” featuring stonemason and sculptor Steve Snyder, one of Andy’s favorite Masons, from Point Pleasant Pennsylvania. Steve has a lifetime of experience working as a mason in Eastern PA and continues to be fascinated with the historical use and application of lime mortars. Steve began his career as a mason and says he would find stones that spoke to him. He would keep those stones and form them into shapes of animals and other objects. This fascination developed and he became a self-taught stone sculptor. Steve now juggles both careers as a mason and sculptor. His home is a testament to his skill and passion, a garden of sculptures surrounds his property where he hosts yearly parties.

If you have an interesting story you would like to tell us which highlights a unique building artisan, a talented architect, engineer or just an inspiring place please contact us and maybe we can shine the limelight on a segment of the story for all to enjoy.