Chimney Rebuild for Atherton Homes

What Atherton's building department lists about chimneys

The Town of Atherton Building Department's ADU/JADU checklist lists fireplaces or chimneys that list, bulge or settle from defective material or deterioration as a substandard-building condition (source: Town of Atherton Building Department - Checklist for ADUs and JADUs).

The same checklist also lists fireplaces or chimneys of insufficient size or strength to carry imposed loads safely as a substandard-building condition (source: Town of Atherton Building Department - Checklist for ADUs and JADUs).

Both items appear on the Town's checklist for accessory dwelling units and junior accessory dwelling units. If you are planning an ADU or JADU and the chimney on that structure leans, bulges or has settled, the Town has named that condition in writing. The Building Department decides how its checklist applies to your project. Our part is to assess the masonry and, where the structure has failed, rebuild it.

Leaning, bulging or settling masonry

"List" is the building term for lean. A chimney that leans, bulges outward or has dropped relative to the house has moved. Once the masonry has moved, the problem is structural, not cosmetic. Repointing joints or sealing a cracked crown can make the surface look better, but neither puts a shifted chimney back in line or restores bond in brick that has pulled apart. A masonry chimney rebuild takes the chimney down past the damaged courses to sound masonry and relays it plumb with new mortar.

When strength or carrying capacity is the concern

The second checklist item covers a chimney that isn't big enough or strong enough to safely carry the loads placed on it. Deteriorated brick, mortar that has turned to sand, and sections that have been patched over and over all reduce what a chimney can carry. During the estimate we look at how much of the masonry is still sound. That tells you whether rebuilding the upper section is enough or whether the work needs to go lower.

Chimney rebuild in brief

A chimney rebuild replaces masonry that has failed instead of patching it. Depending on how far the damage goes, that can mean taking the chimney down from the crown to the roofline, or lower to where the brick and mortar are still sound. It is then relaid with new mortar, a new crown and the flashing reset. It is the fix for a leaning chimney, masonry that has bulged or shifted, and brickwork too deteriorated to hold mortar repairs. For scope and process, read how chimney rebuild works.

When a rebuild fits, and when a smaller job does

Not every cracked or weathered chimney needs to come down. If the chimney is still straight and solid and the damage is limited to mortar joints, a cracked crown or a few spalled bricks, masonry repair or tuckpointing usually makes more sense. A rebuild is the right call when the chimney has moved or the masonry can no longer hold repairs. Our guide to chimney repair vs rebuild walks through how to tell the difference.

If you aren't sure what condition the chimney is in, for example before ADU plans are final or after you notice a new crack, start with chimney inspection in Atherton. That way you know what you are dealing with before deciding on a scope of work.

For more detail on the chimney rebuild service itself, or for the other chimney, fireplace and dryer vent work we handle in Atherton, those pages cover the rest.