Chimney cap installation: what to know

What the job involves, what changes the price, and what to ask a pro.

What chimney cap installation is

Chimney cap installation fits a cap over the flue opening to keep rain, animals and debris out while letting smoke and gases exit. The right size and material match the flue, and the cap is secured so wind does not move it. People call when the chimney is letting in water, when animals have nested in the flue, or when a cap has been lost in a storm.

Signs you need it

  • Water stains on the chimney chase, the ceiling below, or the wall near the flue after rain
  • Birds, squirrels or raccoons heard or seen in the chimney or near the top of the flue
  • Soot or rust staining on the chimney crown or the flue top, which can show water getting in
  • A missing, cracked or loose cap, or a cap that has been blown off in wind
  • A flue that has no cap at all, with debris or leaves collecting at the top

What the pro does

  • Inspect the chimney crown and the flue top from the roof with a camera or from a safe position, checking the flue size and any damage
  • Measure the flue opening and choose a cap size and material that suit the flue, the appliance and the local weather
  • Remove any loose debris or nests from the flue top, and repair the crown or flue top where cracks let in water
  • Fit the cap to the flue, securing it with the fasteners or brackets the cap uses so that wind does not move it
  • Check the cap for clearance, screen openings and secure fit, and confirm it does not block the flue draft

What changes the price

Every job is different, so we do not publish prices. These are the things that move the quote up or down.

  • Flue size and shape, since round, square and multi-flue chimneys each need a different cap
  • Cap material, such as stainless steel, copper or galvanized steel, and the screen type
  • Height and roof pitch, and the access needed to reach the flue top safely
  • Condition of the crown or flue top, including repair of cracks or spalling
  • Removal of nests, animal exclusion work or debris from the flue
  • Whether the cap is a standard fit or a custom piece
  • Permit or inspection requirements, if the work changes the chimney

What a written quote should spell out

  • Cap size, shape and material, matched to the flue dimensions measured
  • Screen type and mesh size, and how the screen keeps animals out
  • Fastening method and brackets used to secure the cap to the flue
  • Crown or flue top repair listed as its own line, with photos of the damage
  • Removal of nests or debris, and any animal exclusion work listed separately
  • Cleanup of debris from the roof and the area around the chimney

Questions to ask before you hire

  • How did you size the cap for my flue, and what measurements did you take?
  • What material is the cap, and how does it handle the local weather and any creosote from wood burning?
  • How is the cap fastened so that wind does not lift it off?
  • Will the cap keep animals out, and what screen do you use?
  • Do you check the crown for cracks, and what do you do if you find them?
  • Will the cap affect the draft of my fireplace or stove?
  • Who is on the roof, and how is the crew kept safe at the chimney?

Red flags

  • A cap installed without measuring the flue, or a cap that is too small or too large for the opening
  • A cap that restricts the flue opening enough to affect draft or to trap smoke
  • No check of the crown or flue top before the cap goes on
  • A cap held only by sealant with no mechanical fastening
  • Work on the roof without fall protection on a steep pitch

What you can do yourself

You can safely look at the chimney from the ground with binoculars and check the ceiling and walls below for water stains. Do not climb onto the roof to reach the chimney, since a roof is work at height and chimneys are heavy. Call a pro for a cap, a crown repair, animal removal from the flue, or any chimney with soot or water staining.

Licenses and permits

Chimney cap installation is commonly done by licensed chimney, roofing or general contractors, and rules vary by place. Check with your state and local licensing agency, and the local building office if the work changes the chimney or flue.

Chimney cap installation questions

Will a chimney cap change how my fireplace draws?

It can, if the cap is too small or the screen clogs. A cap sized to the flue and kept clean should not block the draft. Ask the installer how the cap was sized for your flue.

What material should the cap be?

It depends on the appliance and the local weather. Stainless steel and copper are common choices. Ask the installer how the material handles the fuel you burn and the moisture where you live.

Can animals get in through the screen?

Not if the screen is the right mesh size and is fastened all around the cap. A pro should check the screen and close any gap at the crown or flue top.

Should I replace a cap that is only rusty?

Possibly. Light surface rust may be cleaned, but a cap with holes, a loose screen or a cracked base should be replaced. A pro should check the cap and the crown together.

About this guide

This national guide is written and checked by infinibell. Rules and conditions differ by place, so local pros are credited on guides for the cities they serve, not on national ones.

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