Brooklyn’s brick rowhouses are full of arches, over windows, doors and entrances. The joints in those arches are not like the joints in the flat wall around them. They help hold the arch together, so they are pointed with more care and never all at once.
A brick arch is made of wedge-shaped units called voussoirs, and it stays up because they press against each other through the mortar between them. When that mortar deteriorates, the arch transfers load less well and individual bricks can start to shift. A failed joint in a flat wall mostly lets water in. In an arch it also loosens the structure.
As a brick pointing contractor in Brooklyn we check the shape of every arch before touching its joints, and we open only a few at a time. Where the arch has already dropped or its bricks have moved, repointing in Brooklyn is the wrong fix, and we say so before any work is priced.
Four things that make an arch joint different from the rest of the wall.
An arch works by its bricks pressing against one another, and the mortar between them is part of that. On a Brooklyn rowhouse a deteriorated arch joint weakens the arch as well as letting water in.
In a rough brick arch the joints widen toward the outer edge and narrow toward the opening. Each Brooklyn arch joint is filled along its whole taper, not just to a uniform line at the face.
When arch mortar fails, individual voussoirs can slip out of line. The first signs on a Brooklyn front are often a keystone sitting lower than it should, or a crack following the curve.
If the arch has dropped or its bricks have shifted, new mortar cannot pull it back into shape. The work then becomes rebuilding, as set out on our brick repair and installation Brooklyn page.
Sighting along the curve, checking that the keystone and the bricks either side of it sit where they should, and looking for cracks that follow the arch. That decides whether a Brooklyn arch can be pointed or needs more.
Mortar comes out of a small number of arch joints, those are refilled, and only then does the next group open. The Brooklyn arch keeps most of its joints intact throughout.
Every Brooklyn arch joint is packed along its whole wedge, from the wide outer end to the narrow inner one, so the bricks bear evenly again once the mortar has hardened.
Most of a brick wall forgives a hurried repointing. The arches over the windows and doors do not. Rake out every joint in an arch in one pass and the bricks lose much of the contact that keeps them in place, which is exactly how voussoirs start to shift. Check the shape first, open a few joints at a time, fill each one along its full wedge. On a Brooklyn rowhouse, ask how the arches will be handled before anyone starts on the walls around them.
Rowhouses with arched windows and entrances run through Park Slope, Bed-Stuy, Crown Heights, Clinton Hill and Prospect Heights.
See brickwork contractor Brooklyn for our other brick work in the borough, or brick pointing NYC for how joints are cut out and filled.
Browse our gallery to explore the outstanding projects we’ve successfully completed, highlighting our expertise.
A voussoir is one of the wedge-shaped bricks or stones that make up an arch. They lock together as the arch carries weight, with the mortar between them part of that contact. On Brooklyn rowhouses, arches over windows and doors are built from voussoirs, often with a keystone at the top.
Because in a rough brick arch the bricks are not cut to a wedge, so the joints do the shaping. They widen toward the outer edge and narrow toward the opening. When a Brooklyn arch is repointed, each joint has to be filled along that whole taper.
No. Arch joints help hold the arch together, so removing mortar from all of them at once can let the bricks shift. On a Brooklyn rowhouse the arch is checked for shape first, then pointed a few joints at a time while the rest stay in place.
Usually because the joints have deteriorated and the voussoirs have started to shift. A dropped keystone means the arch has moved, which pointing cannot correct. On a Brooklyn front that calls for rebuilding the arch to its original shape rather than simply renewing its mortar.
Yes. Mortar deterioration in arch joints reduces the arch’s ability to transfer load, so renewing failed joints restores the contact the bricks rely on. It cannot correct an arch that has already moved, which is why a Brooklyn arch is checked for shape before it is pointed.
