Your local chimney repair team in Malibu Groves

Reading cracks in chimney masonry

Cracks in a chimney fall into two very different groups. Hairline cracks in mortar joints and thin gaps where mortar has let go of the brick are maintenance items, and BIA guidance lists both among the conditions that call for repointing.

The second group looks different. Cracks that run through several bricks, cracks that climb in a stepped or diagonal line and masonry that has moved out of plane are conditions BIA maintenance guidance treats as structural. It says issues like these generally warrant an investigation by a professional engineer to find the cause and the right repair.

Filling a structural crack with mortar changes how it looks and does nothing about why it opened. When the first group turns up, it is priced as joint repair. When the second group turns up, the estimate says so in plain words and recommends an engineer's evaluation before any structural work is priced.

The metal top of a framed chase

The top of a chase is sheet metal, and on a factory-built chimney it is part of the system. One maker's instructions, DuraVent's for its DuraChimney II chimney, set the chase top flashing on spacers above the framing, leave a ventilation opening around the pipe, seal a collar to the pipe just above the flashing and place the chimney cap above that.

A flat or sagging top holds water, and rust starts where water sits, then runs down the siding as streaks. A top sealed tight to the pipe or pushed down onto the framing can also close off the ventilation space those instructions call for.

Replacing it means matching the chimney system underneath, not only the size of the box. Our chase cover replacement service checks the points below before a new top is specified, and the estimate lists the top, the collar and any framing repair as separate items.

• The chase size and the pipe diameter
• The collar and its seal to the pipe
• Rot or rust in the framing under the old top
• Clear ventilation space around the pipe

A damper that will not open or close fully

A masonry fireplace is supposed to have a damper. Under the Florida Building Code it is a ferrous metal damper, installed in the fireplace or in the chimney that vents it, and operable from the room. A typical one is a metal plate in a frame just above the firebox, moved by a handle or a rod.

Rust sets in on the plate and frame, and then the damper sticks halfway, the handle turns without moving it or it closes with a gap. EPA wood-burning guidance lists a damper that is not open wide enough among the conditions under which creosote tends to build up. One that will not close leaves the flue open to the house.

Rust on a damper is also a clue that water is getting in from above, so the top gets a look too. Our chimney damper repair service decides between freeing the old damper and replacing it, and your Malibu Groves estimate lists the damper and any repair at the top as separate items.

How a chimney is tied to the house

A chimney built against an outside wall is meant to be fastened to it. Brick Industry Association guidance says single-wythe chimneys should be attached to the structure, generally with corrosion-resistant metal ties.

Those ties sit out of sight. When they rust through or were never installed, the only signs may be a gap opening between chimney and siding, a crack running up the line where the two meet or trim pulling away. The same guidance has the layers of a chimney more than one wythe thick joined with metal wire ties where the masonry itself does not lock them together, so ties can matter inside the chimney as well as at the wall.

Where anchors or ties have failed, BIA maintenance guidance describes proprietary retrofit anchors set through small holes drilled in the masonry, usually in a mortar joint, and attached to the structure behind, with the anchor maker consulted on each product. It says such anchors improve the stability of the masonry. Our crew in Malibu Groves checks the joint between chimney and house during the inspection and writes any re-anchoring into the estimate.