There is something very gratifying in restoring an historic building.

An array of emotions is created from the moment a project is conceived.

It starts with an appreciation of the structure, its design, composition and overall architectural statement. Sometimes it is difficult to visualize these great characteristics in a building because they are often masked by decades of atmospheric pollution, painted graffiti and structural distortions caused by years of neglect and weather infiltration.

But to the trained eye these “masks” merely represent the difference between a building’s obscurity and its taking on a new life of its own, a resurrection so to speak.

It is not uncommon for a building to go unnoticed for years. Then, seemingly out of nowhere, a scaffold is erected, covered with tarps or the latest innovative wrap depicting an ornate facade from who knows where. Weeks, then months go by, with only the whirring sounds of saws, grinders, cleaning equipment and voices speaking a language all unto themselves.

Proper Process

Donning a helmet and entering this world behind the tarps reveals a process few experience.

It generally begins, once the restoration team is in place, with the cleaning process. Depending on the material composition used in the original construction, a number of sample areas or ‘mockups’ are done to ensure that the least intrusive but effective method is chosen. As is the case with most facets of restoration work, especially historically significant ones, less is more. Less chemicals, less removal, less replacement Â… well, you get the picture.

The restoration team, usually consisting of the owner or owner’s representative, the architect, the contractor and in many cases a restoration consultant, will then view the cleaning ‘mockups’ and decide which cleaning method will be used. The intent is not a pristine result, but rather a surface cleaned of its most obvious pollutants. Once this has been determined, a full-scale cleaning operation can begin.

Generally, the next step in masonry restoration is cutting out the existing mortar joints that are defective. Joints between the brick or stone elements of the building can become defective due to, among other things, erosion, separation or displacement, or continued standard maintenance repointing. One of the problems with repointing is that the mortar used is much too hard. In fact, it can be harder than the brick or stone host material into which it is incorporated.

The result is often more damaging to the building than if no repointing had been done at all. As movement occurs – and all buildings move – the weaker element, in this case the brick or stone, must absorb the movement which often winds up cracking, splitting or actually spalling off the building.

A good example of this is buildings with mortar joints that appear to be extruded or raised from the face of the wall, and the brick or stone appear to be sunken or recessed with cracks or large areas of the face chipped off. To repair this problem, the old mortar is removed with diamond bladed grinders usually to a depth of three-fourths of an inch.

Extreme care must be used to prevent the brick or stone from being chipped or nicked. When cutting is complete, the joints are then flushed to remove any remaining dust or debris. Repointing can now proceed.

Rebuilding

Another phase of masonry restoration is the rebuilding process. As is often the case with buildings that have been neglected for long periods of time, water infiltration is a major contributor to severe damage or displacement. When water is allowed to penetrate the wall via open joints, tired flashings, etc. for long periods of time, it can deteriorate the mortar, leaving voids throughout the wall system. These voids then trap the water within the wall and freeze during cold weather.

The continuation of freezing and thawing cycles forces the masonry to move from its original location. Continued freezing and thawing creates larger voids, which can lead to movement so severe that dangerous conditions and even collapse are a possibility. In these cases rebuilding is necessary.

When rebuilding sections of historic structures, photographic documentation is performed prior to dismantling. All elements to be rebuilt are numbered both on the photo and stone or brick to ensure reinstallation in their original locations, using the photographs as a guide.

If the entire structure is being repointed (with the proper strength mortar), the mortar used at the rebuilt sections will be raked back and allowed to cure. Then, the entire wall area, including the rebuilt sections, will be repointed together. The entire area is redone because mortar can cure at different shades or “colors,” depending on its depth. A masonry unit installed in a full bed joint of mortar, as in the rebuilt section, could cure at a different rate than the surrounding area that was repointed at three-fourths of an inch deep. This could result in varying colors throughout the wall or even a checkerboard effect if many areas were rebuilt and not raked back and pointed together with the rest of the wall.

After a final cleaning to remove all excess mortar and residual dust, the project is complete. The tarps are removed and the scaffolding comes down. The true measure of success to a restoration contractor is the passersby overheard to say, “Yeah, so what did they do?” Music to my ears.