Spalling chimney brick repair that deals with the cause in Forest Hills

Choosing the mortar that goes around new bricks

Around replacement bricks, the Brick Industry Association calls for a mortar whose physical properties resemble the existing mortar, and it warns that the wrong mix can make the surrounding masonry spall and crack. It generally recommends Type N for modern work and Type O where a more cement-rich mortar would be too strong.

Color matters too. BIA suggests comparing new mortar samples with the existing mortar both wet and fully dry, since mortar changes color as it dries.

We match the mortar to the chimney rather than reaching for the strongest bag available, and describe the result you can expect.

Setting the replacement brick

BIA's maintenance guidance lays out the method. The surrounding bricks are dampened but allowed to absorb the surface water, the replacement brick and the opening are fully buttered with mortar, and the brick is centered and pressed into place.

Excess mortar is struck off, the joints around the new brick are pointed to make sure they are full, and they are tooled once the mortar is thumbprint hard to match the profile of the existing joints.

Full joints around the new unit matter as much as the brick itself, because gaps there would let water straight back into the repair.

Deciding how many bricks to replace

The repair area is set by the condition of each brick and the masonry around it. Isolated damaged units in sound surroundings can usually be replaced one at a time. Clusters of failed bricks, or failed bricks alongside worn joints, can call for a larger section.

We mark the units that have failed, note the ones worth watching and explain the difference. The goal is to keep every sound brick while removing every one that will not last.

The estimate shows the number of units or the area involved, so you can see how the price relates to the work.

When a partial rebuild makes more sense

Selected brick replacement suits a chimney with isolated failed units. When failed bricks are widespread, or the section above the roof has loosened as a whole, replacing units one at a time can cost more and last less than rebuilding the affected section.

The Brick Industry Association lists widespread spalled brick among the conditions that can indicate a structural problem. If your chimney is at that point, we say so and explain the rebuild option alongside the repair, so you can compare them honestly.