Honest chimney repair for Johnson Village homeowners

Chimney repairs and a new roof in the right order

If a new roof is coming, the chimney work should come first. Crown repairs, rebuilt courses, repointing and new counterflashing all happen at or above the roofline, and doing them after the roofers finish means working over and around brand new roofing at the base of the chimney.

Flashing is where the two jobs meet. The Florida Building Code requires flashing around roof openings, and at a chimney that means base flashing worked in with the roofing and counterflashing set into the masonry. Deciding who installs which layer before either trade starts keeps the laps in the right order and leaves no gap between them.

Mention the reroof at the free inspection. For homes in Johnson Village, the estimate then puts the chimney work ahead of the roofing and says which flashing layer we install and which one belongs to the roofer.

Flashing metal that lasts

Flashing lives in the wettest spot on the roof. BIA guidance notes that corrosion-resistant sheet metal flashing is required by most building codes, and the Florida Building Code requires metal flashing at wall and roof intersections and around roof openings to be corrosion resistant, with a minimum thickness for each kind of metal.

BIA also says quality flashing materials should be specified because replacement may be expensive and troublesome. Replacing it means cutting out the joints that hold the counterflashing and working the roofing back around the chimney, so a thin or poor metal that fails early can cost far more than it saved.

Our crew uses corrosion-resistant metal at or above the code's minimum thickness. The metal is named on the estimate, so you know what is going into the one part of the chimney nobody wants to open twice.

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

Caring for a chimney after the repair

Fresh mortar, concrete and stucco need time to cure. The Florida Building Code sets waiting periods between stucco coats for that reason, and patching and sealing products usually carry their own. What care a repair needs depends on the material used.

Keep paint, sealers and coatings off new work until the product maker allows them. On newly laid brickwork a fairly even white film can appear as the masonry dries. Brick Industry Association guidance on efflorescence calls it new building bloom and says that in most cases it dissipates over time once the brickwork is allowed to dry. Bloom that keeps coming back is a different matter.

The first fire waits until the flue work is complete and cured. Before lighting it, ask whether the repaired flue is ready, because the answer depends on what was used and how long it needs. Keep ladders and foot traffic off new work at the top for a while as well.