Historic Masonry Restoration
Most of the masonry damage we see on old buildings was not caused by age. It was caused by someone trying to fix the building with the wrong materials. That is the single most important thing to understand about old brick and stone, and it is the thing the rest of the industry gets wrong most often.
Heritage Restoration repairs and restores historic masonry the way it was meant to be done, with materials that work with the building instead of against it. We handle brick and stone repair, repointing, chimney work, stone foundation repair, parging, and crack repair, and we coordinate specialized masonry trades on larger projects while making sure the work follows preservation principles from start to finish.
Why the Mortar Matters More Than Anything
There is one principle that governs all historic masonry work. The mortar has to be softer than the brick or stone it holds together. The joint is supposed to be the part that wears out, because mortar is easy to replace and brick is not.
Old buildings were built with lime mortar, which is soft, breathable, and a little flexible. It lets moisture move out through the joints, it flexes with the building as it expands and contracts through the seasons, and when it wears down, you simply repoint it. That is the system working exactly as designed.
Portland cement, the gray modern mortar most contractors reach for, is harder and denser than old brick. When you point at an old wall with it, you reverse the whole system. Moisture can no longer escape through the joints, so it forces its way out through the face of the brick instead. Then New England's freeze-thaw cycle takes over. The trapped water freezes, expands, and breaks the face of the brick right off. The mortar survives, and the irreplaceable historic brick is destroyed. We see it constantly, and by the time it shows up, the damage is usually permanent.
This is not a matter of opinion. The National Park Service lays it out plainly in Preservation Brief 2, the federal standard for repointing historic masonry. Replacement mortar has to match the original, and it has to be softer and more breathable than the masonry around it. Using lime mortar on an old building is simply doing it right.
What We Do
Our masonry work covers the range of what an old building needs:
Repointing historic brick and stone with properly matched lime mortar
Brick and stone repair, including replacing spalled or damaged units with matching material
Chimney repair and restoration, from joints and crowns to flashing
Stone and fieldstone foundation repointing
Parging and crack repair using breathable, compatible materials
Mortar matching and analysis when a project calls for it
On every one of these, the goal is the same. Use materials that match what the building was built with, fix the underlying water problem rather than just the symptom, and leave the masonry able to breathe the way it was designed to.
Doing Repointing Right
Repointing is straightforward in concept and easy to do badly. The old mortar gets raked out to a proper depth, and fresh mortar gets packed in to match the original in composition, color, texture, and joint profile. The part most people get wrong is the removal. Power grinders in unskilled hands chew up the edges of the brick and widen the joints, and that damage does not come back. The work takes patience and the right hands, and it is worth doing carefully because a proper repointing job should last fifty years or more.
Common Questions About Historic Masonry
Why can't you use Portland cement on old brick?
Because it is harder than the brick, it causes the brick to fail. Old brick is soft and porous and was built to work with soft lime mortar that lets moisture escape through the joints. Portland cement seals the joints up tight, so when water gets into the wall, it can no longer get out through the mortar. Instead, it escapes through the face of the brick, and when that trapped moisture freezes in winter, it breaks the brick face off. The mortar outlasts the brick, which is exactly backward from how masonry is supposed to work. The joint should be the sacrificial part, because mortar is easy to replace and historic brick is not.
What is the difference between repointing and tuckpointing?
People use the words interchangeably, but they are not quite the same thing. Repointing is the real work. It means raking out the old, deteriorated mortar from the joints and replacing it with new mortar that matches the original. It protects the wall and keeps water out. Tuckpointing is technically a decorative finishing technique that uses two colors of mortar to create the look of very fine, crisp joint lines. In everyday conversation, most people say tuckpointing when they mean repointing. What matters for your building is that the repointing is done correctly, with the right mortar and proper technique.
How often does brick need to be repointed?
A good repointing job done with the right mortar should last a long time, often fifty years or more, sometimes much longer. How long depends on exposure, the quality of the original work, and the climate, and New England's freeze-thaw cycle is hard on masonry. The signs that it is time are easy to spot once you know them. Mortar that is crumbling, powdery, or can be raked out with a key. Joints that have eroded back noticeably. Damp interior walls, white staining, or brick that is starting to flake. Repointing is normal maintenance, not a sign that something has gone badly wrong.
How can I tell if I have lime mortar or Portland cement?
Age is the first clue. A building from before about 1880 almost certainly has lime mortar, anything built after the 1930s is likely Portland cement, and the years in between are a transition. There are also a couple of simple tests. Lime mortar is soft enough to scratch and crumble with a key, while Portland resists it and stays hard. A drop of white vinegar will fizz noticeably on lime and barely react on Portland. Lime mortar also tends to be lighter and creamier in color, sometimes with little white flecks in it. For anything important, a proper mortar analysis identifies the exact makeup so a match can be mixed, and we coordinate that when a project calls for it.
Why is my old brick crumbling or flaking?
That flaking and crumbling of the brick face is called spalling, and it almost always comes down to water and freezing. Porous brick soaks up moisture, the water freezes and expands in winter, and the face of the brick breaks away. Hard Portland cement repointing makes it worse by forcing moisture through the brick, and so do non-breathable sealers and paint that trap water inside. Once a brick face has spalled it usually has to be replaced, since, unlike mortar, you cannot just repoint it. The important thing is to find and fix the source of the water first. Replace the brick without solving the moisture problem, and you will be doing it again before long.
Should I seal or paint my historic brick?
Usually not. Old brick and lime mortar are built to breathe, and painting or sealing them traps moisture inside the wall, which leads to the same efflorescence and spalling you were probably trying to prevent. Paint also locks you into repainting every few years, and once historic brick is painted, it is very difficult to ever get back. If a building was never painted, the best thing you can do is leave the masonry exposed and keep it properly repointed. If a coating is truly wanted for some reason, the only appropriate option is a breathable one like limewash. And brick should never be sandblasted or power-washed, since that strips the hard outer surface and opens the door to faster decay.
