Chimney Cowls

A chimney cowl is a usually hood-shaped covering used to increase the draft of a chimney and prevent backflow. The chimney cowl, usually made of galvanized iron, is fitted to the chimney pot to prevent birds or wind blowing the smoke back down into the room beneath. No doubt named for the resemblance of many designs to the cowl garment worn by monks, they have been in use for centuries.

Jackdaws nest in chimneys jackdaws are a little bigger than a black bird with a gray neck. People say they have crows nesting in there chimneys but crows do not nest in chimneys, if you have this problem number 1 pest control in west sussex can help you by removing the jackdaw nest and fitting a chimney bird guard for you. Number 1 pest control will sort your squirrels nest problems to as well as jackdaw nest in your chimney.

When using an open fire to heat a room the smoke rises through a flue to a chimney pot on the roof. Under normal conditions the warm air from the fire will rise up the chimney taking the smoke with it and dispersing it at rooftop level where it is less of a nuisance. When you have a disused chimney you can fit a chimney c cap to stop rain and jackdaws getting in your chimney.

All the chimney cowls sold are chimney sweep friendly so the chiney sweep will be able to sweep the chimney to the top into the chimney cowl and some cases still see the chimney sweeps brush at the top for luck. In strong winds the force of the wind may overwhelm the updraft and push the airflow in reverse down the flue. Smoke will then fill the room it is intended to heat posing a health and fire risk, causing discomfort and dirtying furnishings.

When raw coal rather than smokeless fuel is burnt, which was the case for centuries before clean air legislation took effect, then the amount of smoke is considerable and measures to prevent backflow occurring are a necessity.

Another secondary function for a chimney cowl is to prevent birds (jackdaw)and squirrels from nesting in the chimney. Euro cowl and top guard are the common chimney cowls used colt cowls are good to.They often also act as a rain guard to keep rain from going down the chimney. A metal wire mesh is sometimes added as a spark arrestor. Wooden cowls were used on oasts to prevent the ingress of rain into kilns, and create a flow of air through the kiln.

A H-style cap (cowl) is a chimney top constructed from chimney pipes shaped like the letter H. It is an age-old method to regulate draft in situations where prevailing winds or turbulence cause downdraft and backpuffing. Although the H-cap has a distinctive advantage over most other downdraft caps, it fell out of favor because of its bulky looks. It is found mainly in marine use but has been gaining popularity again for its energy saving functionality. The H-cap stabilizes the draft rather than increases it. Other downdraft caps are based on the Venturi effect, solving downdraft problems by increasing the updraft constantly resulting in much higher fuel consumption.


Designed to: Cure smokey fireplaces. Prevents downdraughts by creating a positive airflow whatever the wind direction. Suitable for all fuel types. Also prevents birds, vermin, and rain entry.

Finish: Natural aluminium and powder coat painted terracotta or cotswold stone. *Base flange and fittings all in 316 stainless steel.

Maintenance: High dome allows effective sweeping. Size: A universal fitting fits 125mm (5"), to 250mm (10") chimney pots.

Approvals: BS715 1989 British Gas Certificate No. AE1/92/3.

Optional extras: Stainless steel birdguard which must be fitted when burning gas or oil. An adapter plate is required when external diameter of flue is less than 200mm (8").

Euro Topguard

Designed to: prevent birds, vermin and leaves entering chimney flues whilst maintaining flue efficiency. Provides good ventilation and added protection against wind and rain entry. This model can be used in conjunction with pot hangers (see picture). Finish: Basic model is zinc primed and powder coat painted Terracotta or Cotswold Stone. The stainless steel version is also supplied in Terracotta or Cotswold Stone colours or unpainted and should be specified when highly corrosive fuels are burnt. Maintenance: The high dome allows for effective sweeping without the need to remove the cowl from the chimney pot. Sizes: Fits pots from 125mm (5”) to 250mm (10”) Approvals: BS5871 (terminals up to 250mm (10”).

Chimney Liner

10 STAINLESS STEEL CHIMNEY LINER FACTS 1. The best stainless steel chimney liners have metal alloys ranging from 316TI to AL29-4C.

2. 316TI is a stainless steel alloy with a small amount of titanium added to it which helps protects against corrosion.

3. Liners from chimney accessories are made to be flexible to get around any dog leg or smoke shelfs.

4. A seamless vent, is the safest way to correctly vent from your unit up and out of your home!

5. Not all stainless liners are the same. What some don't realize is that stainless steel comes in many different grades of alloy.

6. A stainless steel liner, made with one of the above alloys, should be guaranteed for the life of your home, make sure it is!

7. When a metal chimney liner is installed, it is required by Underwriters Laboratory (UL) to be insulated on the outside of the liner.

8. The National Fire Protection Association standard 211 (NFPA 211) also requires all liners to be insulated around the outside. Insulating the liner prevents heat transfer , from a chimney, to the outer walls of the chimney. Additionally, insulating the liner contains the flue temperature within the liner thus producing a hotter flue temperature which naturally increases the draft of the venting system.

9. Some liners, will increase the efficiency of your heating unit, usually at least 10% to 15%, which also SAVES YOU MONEY!

10. Finally, when properly installed, it is not only the safest way, but the most cost effective way to KEEP YOU AND YOUR FAMILY SAFE!

Flue Pipes

Flue pipe materials need to be suitable for both the temperature at which the appliance operates and the type of oil being used. Stainless steel is an ideal and suitable material for oil-fired appliance flues. Aluminium lined flue systems intended for gas fired appliances should not be used.

1.5.8 Flue Areas and Cross Sectional Areas The cross sectional area of an open flue must not be less than that of the boiler flue socket and should normally maintain that area throughout. Some manufacturers' instructions may require variations from this and should always be checked.

Output of Appliance Chimney Diameter

Up to 20kW 100mm

From 20kW to 32kW 125mm

From 32kW to 45kW 150mm

If the flue is of square section, it must have a cross sectional area equivalent to that of the circular chimneys noted above. It must be borne in mind however, that the size requirements noted above must not be reduced.

An important design factor is that the cross sectional area of the flue should be sufficient to take the quantity of combustion gases being emitted by the appliance. The requirement for this is that the cross sectional area of the appliance flue socket outlet must be maintained all the way up the chimney. N.B. Flues of circular cross section, must not have their diameter reduced.

The above advice is taken from BS 5410 Part 1. For specific Regional advice please refer to Section 6 for the Regional Requirements.

1.5.9 Design and Installation Requirements Flues and chimneys must rise vertically and follow a route which avoids the use of any changes of direction if possible. If bends are unavoidable, there should be no more than four offsets (maximum of 2 changes of direction in primary connecting flue and a maximum of 2 changes of direction in the main chimney flue which is also known as the secondary flue), and the flue should rise vertically for at least 600mm before any bends are used.

Horizontal flue runs must be avoided and no bends should have an angle of more than 45° from the vertical (N.B. flue bends are usually designated by their internal angle and should not be less than 135º. 110º and 90º bends must not be used). The run of chimney between bends must not be more than 20% of the total chimney length.

It is important to route the flue so that the temperature of the gases is maintained at the highest possible level. Routes on the outside of a building are less advantageous than internal routes in that respect, and should be avoided if possible. Whatever the configuration, provision should be made for the purpose of inspection and cleaning of flues and chimneys, especially at changes of direction.

Where a flue is to be routed within a void, provision should be made to providing a means of access for the flue to be visually inspected and the integrity confirmed following the completion of the installation and at subsequent service visits. Where access points are provided, they should measure no less than 300mm x 300mm and arranged to allow inspection throughout the length of the flue. No joints within the void should be greater than 1.5m from the edge of the nearest access point. NOTE: Access points should not compromise the requirements of the buildings fire safety, thermal insulation and sound resistance.

The Chimney Sweeps head office is based in Crawley Down, West Sussex (near Gatwick Airport). However, we have small regional offices in west sussex, east sussex, surrey, kent offering you a local service. The chimney sweeps have attended HETAS training courses, enabling us to offer a personal, efficient, knowledgeable and comprehensive chimney service, in your home town.


OUR FULLY COMPUTERISED OFFICE and our trained secretaries are extremely knowledgeable and able TO OFFER ADVICE AND A COMPREHENSIVE AND EFFICIENT AND IMMEDIATE APPOINTMENT BOOKING SERVICE between the office hours of 8am and 7pm Monday to Friday and 9am to 4pm on a Saturday.

The chimney sweeps specialise in all types of property, including caravans, flats, bungalows, sheds, houses, domestic, industrial and business properties including Pizza ovens and launderette flues.

We can guarantee the same TOP-CLASS CERTIFIED SERVICE, whether you require one simple sweep or have a multiple chimney sweeping contract to be completed.

THE CHIMNEY SWEEPS have been sweeping chimneys throughout west sussex, east sussex, surrey, kent.

The chimney sweeps are HETAS and GAS SAFE registered and has attended many courses to improve our knowledge.

These include the GAS SAFE, HETAS, SFAS, and ROSPA Fume Assessing courses, Solid Fuel Appliance Servicing courses and Parkray, Trianco, Aga/Rayburn training sessions. National Association of chimney sweeps (NACS) training courses. We are also Construction Line registered.

Chimney Accessories have all your chimney needs from chimney cowls to stop birds getting in and to help with the chimney draw to liners for woodburners or for open fires.