Spalling chimney brick repair that deals with the cause in New Tampa

Mortar that is harder than the brick

Mortar is meant to be the weaker, more permeable part of a brick wall. The National Park Service explains that repointing mortar should be softer and more vapor permeable than the bricks, and that mortar stronger than the units can cause damage such as cracking and spalling.

When hard mortar surrounds softer brick, moisture and movement stresses end up in the brick instead of the joint. Replacing bricks in that situation without addressing the mortar can repeat the damage.

We compare the existing mortar and the bricks before choosing the repair mortar, and explain the choice on the estimate.

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.

Safety around a chimney that is shedding brick

A chimney that is dropping pieces can drop larger ones. Keep people and pets away from the area directly below it, particularly doorways, walkways and patios, until the loose material is dealt with.

Do not climb onto the roof to pull at loose bricks or knock off hanging pieces. Brick that looks loose from the ground may be more or less secure than it appears.

Tell us about entrances and outdoor areas below the chimney when you call, so the work can be planned with protection in place.

If a piece falls onto the roof, leave it where it is and mention it when you call.

Exterior chimney brick and firebox brick are different jobs

The bricks inside a firebox are firebrick, set to handle direct heat, and they are repaired with materials made for that purpose. The bricks on the outside of the chimney are building brick exposed to the weather.

This service covers the exterior masonry. If the firebox also has cracked or loose brick, we note it and explain the firebox repair separately, because the materials and methods are not the same.