The cap is the least expensive part of a chimney and one of the most important. It is a metal hood with mesh sides fitted over the flue opening. It keeps rain out of the flue, keeps birds, squirrels and raccoons from moving in, and stops sparks from landing on the roof. On a prefab chimney, the chase cover does a related job: it is the sheet-metal lid over the whole framed chase, with a collar where the pipe passes through.

  • Single-flue and multi-flue caps sized to the chimney
  • Stainless steel and copper caps with spark-arrestor mesh
  • Custom chase covers with cross-breaks so water runs off
  • Storm collars and flashing at the pipe sealed
  • Top-sealing dampers as an alternative on masonry flues

Why chase covers fail here

Builders commonly fit galvanized steel chase covers. Galvanizing wears off, the flat metal sags, water pools on it and rust follows. A rust streak running down the chimney siding is the visible sign. Hail speeds this up by denting the metal so it holds water and by cracking the coating. A replacement in stainless steel, formed with a slight peak and a drip edge so water sheds, is the lasting repair.

Choosing a cap

Stainless steel is the standard recommendation: it does not rust and it usually carries a long warranty. Galvanized caps are cheaper and have a shorter life. Copper lasts and costs the most. The mesh should be small enough to stop animals and embers without clogging quickly. A cap must be sized and fastened for the specific flue; a loose cap leaves with the first strong wind, and a cap that sits too low can restrict the draft.

After a hailstorm

If your roof is being inspected for hail damage, ask that the chimney cap, chase cover and flashing be included in the assessment and in any insurance claim. These parts are often overlooked, and damage to them causes leaks that appear months later.

Common chimney caps & chase covers situations in Fort Worth

  • No cap at all, and rain or birds in the flue
  • Rust streaks down the side of the chimney chase
  • A dented or split cap after hail
  • Animals or nesting material in the chimney
  • Water in the firebox after a storm

Chimney Caps & Chase Covers FAQs

Does every chimney need a cap?

It should have one. An uncapped flue takes in rain with every storm, which rusts dampers and fireboxes and damages liners, and it is an open invitation to birds and animals. A cap is a small cost against the repairs it prevents.

Will a cap keep chimney swifts out?

Yes. A properly fitted cap with mesh prevents swifts from entering. It has to be installed outside the nesting season, since an active nest may not be disturbed; schedule it for late fall or winter after the birds have left.

This content is reviewed by the Fort Worth TX Chimney Sweep editorial team and informed by licensed-contractor sourcing, manufacturer documentation, and established industry standards for Chimney Services. Read our editorial standards.