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At BES, we stock a practical range of ventilation cowls designed for domestic and commercial use. Whether you're covering an air brik or finishing a roof duct, our cowls are built from durable materials and available in popular sizes for a secure and professional installation.
Shop the full range online today and get your ventilation cowls delivered next working day with BES.
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Ventilation cowls are protective covers fitted to the outside of ventilation ducts, chimneys, or air bricks and have the purpose of allowing airflow while preventing draughts, rain, debris, and pests from entering the system. By improving airflow and reducing the risk of downdraught, a correctly fitted cowl helps maintain a safe, efficient, and long-lasting ventilation system.
BES, we stock a practical selection of ventilation cowls ready for next-day delivery, making it easy to finish your installation with confidence.
Air brick cowls are designed to be mounted over air bricks, protecting ventilation openings from wind, water, and dirt while still allowing free airflow. They also prevent birds, insects, and other small animals from entering ductwork and causing blockages.
Our range includes air brick cowls in terracotta or brown finishes, in sizes:
6" x 6" (KVH8 Air Brick Cowl 6" X 6" Terracotta & KVH8 Air Brick Cowl 6" X 6" Brown)
9" x 3" (KVH12 Air Brick Cowl 9" X 3" Brown & KVH12 Air Brick Cowl 9" X 3" Terracotta)
9" x 6" (KVH17 Air Brick Cowl 9" X 6" Terracotta & KVH17 Air Brick Cowl 9" X 6" Brown)
9" x 9" (KVH99 Air Brick Cowl 9" X 9" Brown)
The cowls in our selection are manufactured for strength and weather resistance, making them a reliable choice for both internal and external wall installations.
The Universal Roof Cowl in our range is designed for use with round ducting and fits diameters from 100mm to 160mm. Ideal for roof-mounted ventilation systems, this cowl provides effective draught prevention while protecting against rain ingress. Its universal sizing makes it highly versatile across a range of ductwork installations.
When selecting a cowl, consider:
Application: Air brick cowls are used with wall vents, while roof cowls finish ductwork at roof level.
Size: Always match the cowl to the size of the air brick or duct (our universal model makes this easier for roof applications).
Material and finish: Terracotta and brown finishes blend with most external brickwork. For roof installations, aluminium or plastic cowls are favoured for durability and weather resistance.
Problem-solving: Where draughts and rain are a recurring issue, choose a cowl specifically designed to block these while maintaining airflow.
Ventilation cowls are designed for straightforward installation:
Air brick cowls are fixed over the air brick opening using screws, with minimal tools required.
Roof cowls simply slot into the ducting and are secured in place, ensuring a weatherproof fit.
For safety, always check that the cowl is correctly matched to the system it is protecting, and that it is secured tightly against the building fabric.
With over 50 years supplying the trade, BES combines expertise with service you can trust. All our cowls are sourced for quality and durability, backed by competitive pricing and thousands of customer reviews confirming reliability. Ordering is simple through our Quick Shop feature, and with next working day delivery and 30-day hassle-free returns, you’ll always get the parts you need without delay or risk.
From protecting wall vents with a durable air brick cowl to completing a duct system with a universal roof cowl, BES has the products to keep your ventilation systems safe and effective. Browse the range online today and benefit from fast delivery, expert support, and trusted trade-quality supplies.
What is a ventilation cowl?
A ventilation cowl is a hood or cover fitted to the outside of a vent, air brick, or duct, allowing airflow while blocking draughts, rain, debris, and pests.
What are the benefits of fitting a ventilation cowl?
Cowls help prevent cold draughts, improve airflow, reduce moisture ingress, and stop birds or insects from entering the ventilation system.
What types of ventilation cowls are available?
Common types include air brick cowls for wall vents and roof cowls for duct terminations. Other designs (anti-downdraught, rotary, bird guards) are used for specialist chimney or flue applications.
What sizes are BES ventilation cowls available in?
Air brick cowls are available in 6"x6", 9"x3", 9"x6", and 9"x9". Our universal roof cowl fits ducts from 100mm to 160mm.
What materials are ventilation cowls made from?
Air brick cowls are typically plastic in terracotta or brown finishes to blend with brickwork. Roof cowls are often aluminium or weather-resistant plastic for strength and durability.
How do I install a ventilation cowl?
Air brick cowls screw over existing bricks, while roof cowls push into ducting and are secured in place. Always ensure a snug fit to prevent draughts or water ingress.
Where can I buy ventilation cowls online?
BES stocks air bricks and roof cowls in a range of sizes, all available online with fast delivery and 30-day returns.