Stone veneer chimney repair by local pros in Milk District

The layers behind manufactured stone

On a wood-framed chase, one maker's instructions list the assembly in order, sheathing, two layers of water-resistive barrier, galvanized metal lath, a scratch coat, a mortar setting bed, the stone and the mortar joint. Each layer has a job, and a failure in one shows up in the stone.

When a section of veneer comes loose, we look at every layer behind it before resetting anything. Rebuilding the missing layer along with the stone is what makes the repair last.

• Sheathing on the framing
• Two layers of water-resistive barrier
• Metal lath and scratch coat
• Setting bed, stone and joint

Metal lath and how it is fastened

Lath gives the scratch coat something to grip. The instructions we follow call for lath installed to ASTM C1063, typically with corrosion-resistant fasteners every 6 inches vertically and 16 inches horizontally into framing, and self-furred so mortar can wrap behind it.

When we open failed veneer, lath tells a story. Rusted, loose or poorly fastened lath explains stones that pull away in sheets. We replace damaged lath before building the backing back up, and we note the fastening in the findings.

Cutting and placing replacement stones

Replacement stones often need trimming with nippers, a hatchet or a saw. One maker suggests coating cut or broken edges with mortar for the best appearance, turning cut edges up when above eye level and down when below, and placing a cut edge next to a thicker stone to hide it.

Those small choices decide whether a repair disappears into the wall. Our crew cuts outdoors with dust control and sets each piece with the cut where it will not catch the eye.

Fieldstone and rubble stonework

Fieldstone chimneys use irregular stones with wide, uneven joints. Those wide joints are where mortar loss shows first and where water gets in.

Wide stone joints, the preservation brief notes, can call for raking several inches back. We rake out to sound mortar, fill the deep joints in layers and finish them to the existing profile. Small pinning stones that have fallen out of wide joints are reset as part of the work.

What a stone chimney estimate lists

A clear stone estimate separates the work so you can see and approve each part. Ours list the stones to reset or replace, the joints to repoint and how deep, the mortar type and how it will be matched, and any access equipment.

Cap, crown, flashing, drainage and flue items sit on their own lines beside the stone work. Each has its own price, and the total does not change later without your approval.

• Stones to reset or replace
• Joints to repoint and depth
• Mortar type and color match
• Access and site protection
• Related items on their own lines