Chimney Cap Installation in Brentwood - Custom Fit, Lifetime Warranty

If you've replaced a prefab fireplace with a masonry system in the Pacific Palisades hillside or the Riviera section, the chimney cap situation gets more complicated than a straightforward swap. A standard single-flue stainless steel cap on an existing masonry flue runs between $350 and $650 installed, depending on flue dimensions and roof pitch. But a prefab-to-masonry conversion often changes the flue size, shape, or crown configuration. That means the original cap opening no longer matches. We see this constantly in Brentwood homes built in the 1960s and 70s that have since upgraded their fireboxes. The old prefab chase cover gets removed, a proper masonry crown gets built, and then you need a cap sized to the new clay tile liner. That conversion-related cap work typically lands between $550 and $900, because the crown has to be inspected and sometimes repaired before anything gets mounted.

The material choice matters here more than in most inland cities. Galvanized steel caps cost less upfront, but Brentwood sits close enough to the coast that salt-laden air corrodes galvanized metal within three to five years. We install 304-grade stainless steel as the baseline for Sunset Mesa and other westward-facing properties. For homes with multiple flues from a conversion project, a multi-flue cap covers the entire crown in one piece, which also protects the mortar crown joints from rain intrusion. Multi-flue caps in stainless run $700 to $1,200 installed. Every installation includes a mesh screen that doubles as a spark arrestor meeting Los Angeles County fire code, and it keeps raccoons, rats, and barn owls out of your flue. If your chimney hasn't been inspected since the conversion, we recommend scheduling a Level 2 camera inspection before cap installation to confirm the liner is intact.

Our technician starts on the roof with a visual assessment of the crown and flue termination. In prefab-to-masonry conversions, the crown is sometimes a weak point. The original prefab chase was topped with a sheet metal cover, and when the mason rebuilt the flue in brick or stone, the new crown may not extend far enough past the flue walls to shed water properly. We measure the overhang. If it's less than two inches, we apply a CrownCoat sealant before mounting the cap, because a cap alone won't prevent water from pooling against the flue tile and freezing during Brentwood's occasional winter cold snaps. In the Riviera section, where hillside homes face heavy wind exposure from the canyon, we check for any earthquake micro-cracking along the crown that could let moisture in beneath the cap's base.

Next, we measure the flue opening precisely. Converted flues in this area vary. Some masons install standard 8x13 clay liners, while others use round stainless steel liners that require a different cap mount. We carry both clamp-on and screw-mount caps on every service truck. The cap gets positioned, leveled, and fastened with stainless steel screws into the crown or directly onto the liner. Every cap we install includes a mesh screen with openings no larger than half an inch, which satisfies the spark arrestor requirement under California fire code. We finish by running a smoke test from below: we light a smoke pellet in the firebox and verify draft pulls cleanly through the cap without downdraft. On Pacific Palisades hillside properties where wind patterns shift seasonally with Santa Ana events, this test catches problems that a visual-only install would miss. If the crown or flue liner shows damage during any of these steps, we'll walk you through what chimney repair work is needed before the cap goes on.