Honest chimney repair for Bal Bay homeowners

What you can check safely from the ground

You can learn a lot about a chimney without a ladder. Walk around the house, stand back far enough to see the whole stack and use binoculars for the top. BIA maintenance guidance recommends binoculars for observing upper areas up close, along with sketches and notes of what you see. It also suggests looking in different seasons, since some conditions only show in certain weather.

Stay off the roof. Nothing you could see from up there changes what happens next, and loose masonry and a pitched roof are a poor mix. Write down where you saw each thing and bring the notes to the free inspection, where our crew in Bal Bay checks each point you raise up close.

• Mortar that is missing or sits back from the brick face
• Rust streaks running down from the top
• A gap where the chimney meets the house wall
• Plants, stains or white deposits on the brick

Counterflashing set into the mortar joint

How the top edge of the counterflashing is held decides how long it stays tight. BIA guidance sets its edge 3/4 to 1 inch deep in a mortar joint, mortared in solid, so the metal is locked into the masonry itself.

One shortcut is a strip of metal fastened to the face of the brick with a bead of caulk along its top edge. A surface-mounted strip depends entirely on that bead. Once the caulk cracks or pulls away from the brick, water runs down behind the metal and into the very joint it was meant to protect.

Cutting the joint, setting the metal and mortaring it back in takes more time than a caulked strip. It is the detail we price on flashing jobs. The estimate says whether the counterflashing will be set into the joint and which joints are cut and remortared.

White deposits on the brick

A white, powdery film on chimney brick is likely efflorescence. BIA guidance explains that it needs three conditions at the same time, and it forms when water carrying dissolved salts reaches the surface and evaporates, leaving the salts behind.

Those salts show on the brick but usually come from what touches it, such as mortar, concrete or soil. That makes efflorescence a water sign more than a brick defect, and BIA notes it is usually not harmful to the brick itself.

Cleaning comes last. BIA guidance says to identify and correct the source of water and let the brickwork dry before cleaning recurring efflorescence, and light deposits can be removed by dry brushing or with a stiff fiber brush and water. On the estimate, the water repair comes first and any cleaning follows it.

• Soluble salts in or touching the brickwork
• Water in contact with them long enough to dissolve them
• A path through the masonry to a surface where water can evaporate

The shape of a mortar joint sheds water

The finished shape of a mortar joint affects how well it keeps water out. BIA guidance on water penetration says concave, V and grapevine joints best resist water in exterior brickwork, because tooling presses the mortar against the brick into a dense, weather-tight surface.

Other profiles are meant for interior work. Flush, raked, struck and similar joints are not recommended outside, since they either leave the outer mortar unconsolidated or form small ledges where water can pond. The same guidance calls full bed joints an inherent requirement for water-resistant brickwork and says to tool joints when the mortar is thumbprint hard.

Repointed or replaced brick is tooled to a profile that sheds water. BIA maintenance guidance asks for the last layer of repointing mortar to be tooled to match the original profile, so where the existing joints are raked or flush, the estimate explains the choice between matching them and switching to a profile that keeps water out.