Chimney stack with clay pots on a house roof, ready for capping
HETAS-certified sweeps across Essex, Herts & North & East London

Chimney Capping

Rain coming down an old flue, birds nesting in the pot or a cold draught from a fireplace you never use. We sweep the chimney, then fit a vented cap or capping cowl that keeps the weather and the wildlife out while letting the flue breathe. Rated 5.0 from 105 Google reviews.

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Chimney capping

Keep the rain out without sealing the flue in

A chimney cap sits on top of the pot and stops rain, leaves and birds getting down the flue. On a chimney you still use, the cap has to let smoke and fumes out freely. On a chimney you have stopped using, it has to let enough air through to keep the inside of the flue dry. Get that balance wrong and you swap one problem for another, which is why capping a chimney is worth doing properly.

We are Adele and Sian, sisters and HETAS-certified sweeps, and capping is part of the work we do every week. We always sweep the flue before it is capped, so there is no soot, old nest material or debris left up there to block it or rot. Then we fit a cap that suits the pot, the flue and how you use the fireplace, and smoke test to prove the chimney is still doing its job.

Most capping jobs are done from the existing pot in a single visit, alongside a sweep. Dust sheets and an industrial vacuum stay down the whole time, and we show you photos of the pots before and after.

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Chimney capping we carry out

Every job is done at the pot, with the right cap for whatever is underneath it. If something is beyond our trade, we will tell you straight.

Vented caps for disused chimneys

If you have closed up a fireplace, the flue still needs air moving through it. We fit a ventilated cap that keeps rain out but lets the chimney breathe, so moisture does not build up inside the stack and the chimney breast.

Rain caps

An open pot lets rain fall straight down the flue and into the grate. A rain cap with a hood sheds the water away from the opening while leaving the flue clear for smoke on a fire you still light.

Capping cowls for working fires

For an open fire or stove that is still in use, we fit a cowl with a built-in cap that is made for the appliance, so smoke and gases escape and the fire still draws. See our cowls and bird guards page for the range.

Bird-proof mesh caps

Jackdaws love an open pot. A mesh cap or guard stops them nesting in the flue in the first place. If you think something is already up there, read our guide to the signs of a bird nest in your chimney.

Stacks with several pots

Older houses often have three or four pots on one stack. We work out which flue goes to which fireplace and cap each one to suit, so a disused bedroom flue and the working lounge flue each get the right treatment.

Checking an existing cap

Caps rust, blow loose, or the wrong type gets fitted. We check what is on your pots, test the flue and tell you if anything needs changing. A CCTV chimney inspection shows what is happening further down.

When to cap a chimney

Capping makes sense when the flue is letting in something it should not. These are the reasons people usually ring us.

  • You have stopped using an open fire and the pot is still open
  • Rain is coming down into the grate or onto the hearth
  • Damp patches on the chimney breast of a fireplace you no longer use
  • Birds nesting in the pot, or twigs and debris landing in the grate
  • Cold draughts and a sooty smell from a closed-off fireplace
  • Leaves and rubbish building up at the bottom of the flue
  • You are selling or letting a property and want old flues sorted
  • An old cap has rusted through, cracked or blown off

How chimney capping works

Sweep first, cap second. Here is what happens when we come out.

  1. We sweep and inspect

    We sweep the flue to clear soot, old nests and debris, then look over the pot and the top of the stack. Capping a dirty flue just traps the mess inside, so we never skip this step.

  2. We smoke test

    A smoke test shows whether the flue draws properly and whether smoke is escaping anywhere it should not. You can read how it works on our chimney smoke test page.

  3. We recommend the right cap

    We tell you what we would fit and why: a vented cap for a disused flue, a rain cap or capping cowl for a working fire, or a bird guard if nesting is the problem. You get a price before any work starts.

  4. We fit it and test again

    The cap is fixed securely to the pot, then we smoke test again to make sure the chimney still draws as it should. We tidy up and leave you a record of what was done.

Never seal a flue completely A chimney capped solid with no air moving through it traps moisture, and that damp ends up showing on the chimney breast walls inside the house. Just as important, a flue that serves a working fire, stove or gas appliance must never have a non-vented cap on it, because the fumes have nowhere to go and can come back into the room. If you are not sure what is on your chimney, get it checked before you light anything.

When it is a job for a roofer Taking the pots off and capping the whole stack with a slab, re-doing the flaunching, or rebuilding brickwork is work for a roofer or builder, usually with scaffolding. We can sweep, inspect and give you a clear picture of what we found, and point you in the right direction. For the pot and stack problems we can deal with, see our chimney repairs page.

Capping, cowl or bird guard?

They all sit on the pot, but they do different jobs. Here is the short version.

For disused flues

Chimney cap

Closes off the top of a pot you no longer use, with vents so air can still move through. It stops rain and birds, keeps the flue dry and cuts the draught. Not for a fire you still light.

For working fires

Cowl

Sits on the pot of a chimney that is in use. Depending on the type, it helps the fire draw, cuts down-draught or keeps rain out, and it always lets smoke escape. Many cowls have a cap and mesh built in.

For nesting birds

Bird guard

A mesh cage over the pot that keeps birds out but leaves the flue fully open. A good choice for a working chimney where birds are the main problem, and it can be combined with a rain cap.

Not sure which one you need? We will look at the pot and the flue and recommend one. Full details are on our cowls and bird guards page.

In our customers’ own words

Real reviews from homeowners we have swept for.

Open fire and multi-fuel stove

“Done the job and left the rooms spotless. You wouldn’t have known they’d been to clean our open fire and multi fuel stove.”

Steve R.

Routine sweep

“Very professional, friendly, knowledgeable and made absolutely no mess.”

Nina W.

Log burner sweep

“The log burner is performing better than it ever did.”

John E.

Stove service

“Checked my CO2 alarm, tightened the door handle on my burner and cleaned it all.”

Sally M.

Chimney sweep

“I was shocked at how much came out of my chimney yet my house was left all clean and tidy.”

Jackie D.

Chimney and wood burner

“Arrived early. Cleaning chimney and wood burner. Quick, clean, efficient and friendly.”

Jon K.

What our customers say

Reviews from homeowners across Essex, Hertfordshire and North & East London.

Google5.0★★★★★105 Google reviews
  • ★★★★★Google
    They are great. Turned up on time. Done a great job ,very clean. Cleaned my burner up lovely, fixed my rope on my door. Can’t recommend then enough. Definitely will be using the every year from now on
    Luke G.November 2026 · Google review
  • ★★★★★Google
    Recently moved into a property with a log burner, having not experienced the need for getting one cleaned I booked sweep sisters through recommendation and they were spot on! For my house insurance I needed an accredited sweeper which they are. Adele and Sian were so friendly and took care of my home when cleaning and left the room spotless! Spoke through what they had done, would highly recommend, you will not be disappointed!!
    Nicola D.October 2026 · Google review
  • ★★★★★Google
    Sweep Sisters always provide an excellent and professional service. We have used them for the past 3 years and we would fully recommend them to sweep your chimney.
    Donna C.October 2026 · Google review
  • ★★★★★Google
    Having been let down by someone else, we looked at reviews and thought we would try the Sweep Sisters. Great decision. So professional and friendly, quick and super clean job. Very knowledgeable, no one else will be sweeping our chimney going forward.
    Chris A.October 2026 · Google review
  • ★★★★★Google
    Adele came round today (Saturday) to sweep a couple of our chimney stacks, and the service was fantastic from start to finish. She was extremely knowledgeable, professional, tidy and clean, keeping dust to an absolute minimum and making sure everything was properly covered. The CO alarm and smoke evacuation tests were included in the price, and she cleaned the stoves too. I honestly couldn’t recommend her highly enough. We’ll definitely be using Adele for our annual chimney sweeps going forward and wouldn’t consider using anyone else. Fantastic service all round. Highly recommended.
    Paul C.October 2026 · Google review
  • ★★★★★Google
    It was a pleasure to have The Sweep Sisters in my home today. They let me know in advance when to expect them and arrived on time at my door with friendly smiles. Their work on my log burner and chimney was thorough and efficient. No fuss and no mess. I would be happy to recommend them.
    Linda W.October 2026 · Google review
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Chimney capping prices

Every chimney is different, so capping is priced once we have seen the pot and the flue. Ask us for a quote and we will confirm the price before any work starts.

Standard chimney or stove sweep

From £95

Full sweep, visual inspection, smoke test, clean-up and a sweeping certificate for your records.

CCTV flue inspection

From £75

Added to a sweep. A camera run up the flue to check the liner and find damage you cannot see from the fireplace.

Chimney capping

Quoted

Depends on the type of cap, the pot and how many flues need doing. Most jobs are done at the same visit as the sweep.

Cowls and bird guards

Quoted

Priced after we have seen the pot and flue. See our cowls and bird guards page for the options.

Prices are for a single flue. No hidden call-out fees. See all our chimney services, or get in touch for a capping quote.

Where we cap chimneys

We cap chimneys across Essex, Hertfordshire and North & East London. Not sure about your postcode? Send us a message.

Essex

Hertfordshire

North & East London

Chimney capping questions

Should I cap a chimney I don’t use?

Usually, yes. An open pot on a disused chimney lets rain, birds and draughts straight in. A ventilated cap keeps those out while letting air move through the flue, which stops damp building up. We sweep it first so nothing is left inside.

Can you seal a chimney completely?

We don’t recommend sealing a flue solid. Without some airflow, moisture gets trapped and comes through as damp on the chimney breast. A disused chimney should have a vented cap at the top and some ventilation at the bottom, such as a vent where the fireplace was closed up.

Can I put a cap on a chimney I still use?

Only the right kind. A working fire, stove or gas appliance needs a cowl or rain cap that lets smoke and fumes out freely. A non-vented cap on a working flue is dangerous because the gases have nowhere to go. We check what the flue serves before we recommend anything.

How much does it cost to cap a chimney?

It depends on the type of cap, the pot and how many flues need doing, so we price it once we have looked. Capping is often done at the same visit as a sweep, which starts from £95. Ask us for a quote and we will confirm the price before any work starts.

Do you need scaffolding to cap a chimney?

Not usually for fitting a cap or cowl to an existing pot. Taking the pots off and capping the whole stack, or work on the flaunching and brickwork, is roofer work and often needs scaffolding. We will tell you if that is the case.

Will a chimney cap stop birds nesting?

Yes. A cap or mesh guard stops birds getting into the pot. If birds are already nesting, the nest has to be cleared and the flue swept first, and active nests are protected by law, so timing matters. We will advise you on what can be done and when.

From the blog

Chimney advice from Sweep Sisters

Guides, prices and seasonal tips, pulled live from our blog.

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Book a chimney capping visit

Tell us your town, how many pots you want capped and whether the fire is still in use, and we will confirm a date and price.

Prefer to talk? Call 0330 133 2121 or email contact@sweepsisters.co.uk.