Far too often, as I inspect a home, I must endure the agony of watching a well meaning but ignorant mason destroy old historic masonry. Richmond, Virginia has thousands of beautiful solid masonry row houses with ornate brickwork. Many of these lovely buildings are in desperate need of re-pointing, but if I had my way no one would be able to lay a tool to them without a clear understanding of what to do and how to do it. Not only does an improper job look horrifying, but it actually accelerates future deterioration! That changes the event from a cosmetic pity to a catastrophe.
There are many things that can be done in a number of ways, but there is truly only one way to re-point old masonry. If you know a mason, be sure that he receives a copy of this article for the sake of every colonial mason that ever “raised the cotton”.
Rule # 1: Match the existing mortar color. That makes sense, but so few masons actually do it. It seems there are those that could care less and use gray mortar and those that care a bit and use Riverton C-81 (an off the shelf wheat colored mortar).
Have the sand delivered to the job ahead of time. Ship a coffee can of that sand along with several samples of the mortar to be matched to Riverton Corp1111 Riverton Rd. Front Royal, VA 22630 or call 800-558-8887to make arrangements. Riverton produces over 800 colors of masonry and their lab will bag and ship the exact mix needed to match your project.
Rule # 2: Remove enough old mortar to guarantee the new work will stay. A thin layer of new mortar will break loose in a season or two due to freeze and thaw action.
Rule # 3: Moisten your work area. Cement curing is intended to be a chemical process and not an evaporative or absorption process. If you apply wet mortar to a bone dry and thirsty surface, the water will be drawn from the mortar far too quickly which weakens the mortar and compromises the bond between mortar and brick. I used to literally soak tomorrow’s work area before I called it a day.
Rule # 4: Don’t make your mortar too soupy. Wet mortar applied to a damp surface makes for a smeared mess. Believe it or not, I used to actually mix my mortar to the consistency of stone mortar which when carefully applied to a damp surface worked and tooled perfectly. Mix your mortar to a consistency that only clumps when squeezed. This consistency actually is less likely to give up its moisture through absorption of dry adjacent materials.
Rule # 5: Don’t return the mortar joint to the front face of the brick! There are both cosmetic and technical reasons for not doing this and we will cover them both.
Over time the face edges of a brick wear and round. If you point to the surface of the face of the brick the mortar joint will appear to be twice its original thickness. Nothing looks worse than a fat mortar joint.
More importantly, if you bring the mortar out to the face of the brick, the new cement laden mortar will act as a dam trapping moisture in the lower portion of the brick which will accelerate spalling caused by seasonal freeze and thaw. This is also why it is so critical to match your materials softness. If the brick is soft and porous you must do your best to make the mortar equally soft and porous to promote drying and avoid future spalling.
So then, how should we form the new joint? Use a trowel and “tuck pointer” of “slicker” and push the mortar into the joint only to the beginning taper of the weathered edge of the brick. Now, strike or tool the joint with the “tuck pointer” or “slicker”. This process takes considerably more time which needs to be taken into account when pricing a large project. But, to do otherwise is bordering on criminal. The damage is irreparable and permanent.
Rule # 6: Brush the work with a genuine horse hair brush. You must brush the work because this also, like the tooling, brings cement to the surface to form a nice weather seal. Genuine hair is soft and won’t drag out material.
Rule # 7: Cure your work. I can’t emphasize this step enough. You’ve just applied damp mortar to a system that has been in place and practically bone dry for decades. As stated earlier, cement is supposed to cure chemically over a period of approximately and ideally 28 days. As soon as your work is set, keep it wet for days if at all possible.
Rule # 8: Avoid harsh chemical cleaners. If a mason is careful and uses the stone consistency mortar process he can avoid the need to clean the masonry all together. If cleaning is necessary use the mildest product available and designed for your specific application.
If a mason follows these steps he will preserve the beauty and life of old masonry for generations to come. Also, he will begin to receive telephone calls from historical societies across the country. I did and it didn’t take very long. My first proper point up project was in a sleepy little town in the foothills of the Appalachian Mountains called Bluemont, Virginia. Within weeks I received calls from historical societies regarding work in Georgetown (Washington, DC) and Baltimore, Maryland. I have no idea how either of those people found me.
Michael G. Bryan
MGB Inspection Service, Inc
MGB Publications, Inc.