Chimney Caps and Chase Covers That Keep the Weather Out

Without a cap, every flue is an open shaft from the sky into your living room. Rain runs down it and rusts the damper. Squirrels, birds and raccoons see a dry, sheltered den. Wind pushes down it and blows smoke back into the room. A good cap with a mesh screen fixes all three for a few hundred dollars, which is why it is one of the first things we check at every free inspection.

Newer houses often have a different top. Ocean County has the newest housing in New Jersey, with a median build year of 1982, and many homes there and across the state have factory-built fireplaces in a framed, sided chase. The top of that chase is a sheet-metal pan called a chase cover. When it rusts or dishes in the middle, water pools, works through the seams and runs down inside the chase.

Signs you need this

• No cap at all on top of the flue
• Rust streaks running down the brick or siding
• Birds, squirrels or scratching in the chimney
• Water dripping onto the damper or into the firebox
• A chase cover that sags in the middle and holds water

How we do it

1. Measure every flueAt the free inspection we measure each flue and the crown or chase top, and check whether the old cap is rusted, undersized or missing its screen.
2. Pick the right topA single-flue cap, one cap covering several flues, or a new chase cover with a raised center and drip edges so water runs off.
3. Remove the old oneRusted caps and covers come off. If an animal is living inside, removal comes first and the cap closes the way back in.
4. Fasten for the windThe new cap or cover is secured to the flue or crown and checked for clearance so it does not choke the draft.

Which cap do I need, and what does it cost?

A stainless cap for a single flue typically runs $250 to $500. Chimneys with two or three flues often get one cap covering the whole crown, and custom or multi-flue caps run $425 to $850. Replacing the metal top on a framed prefab chase costs $300 to $700.

We use stainless rather than galvanized steel. Galvanized caps are cheaper on the shelf but rust through in a few years in a wet climate, and then you are buying the cap twice.

Why do Shore chimneys lose caps and chase covers faster?

Salt air speeds up corrosion of any steel near the coast, and Shore houses take more wind. Toms River averages about 52 inches of precipitation a year in NOAA's normals, more than Newark or Trenton. A thin galvanized chase cover on a beach-block house can rust through, and a cap held by a few loose screws can blow off in a coastal storm.

After Superstorm Sandy, FEMA estimated about 72,000 homes and businesses in New Jersey were damaged, more than 40,000 in Ocean County. Homes repaired or rebuilt after the storm are now well into their second decade, and so are their chase covers.

Can a cap fix a smoky fireplace?

Sometimes. If wind is pushing down the flue, a cap that shields the top can help, and so can extending the flue. If the problem is the fireplace opening or a blocked flue, a cap will not solve it. We diagnose draft problems free at the inspection.