The Cast Iron Air Brick Company

cast iron air bricks

For more information see...... Cast Iron Fact Sheets

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cast iron air bricks

cast iron air bricks

A selection of 9"x6" cast iron air bricks

Period Air Bricks

period cast iron air brick

period cast iron air brick

Period cast iron air bricks come in many different designs but often in just two standard sizes the 9"x 6" and the ones shown above, the 9" x 3".  The 9" x 3" is a typical under floor ventilation cast iron air brick and is more or less the size of a standard brick so blends in nicely with the street scene. Often they would be sited at the front and rear of a house at ground level at varying rates. Small terraces would normally have one or two at the front and the same at the back, larger properties utilising additional grilles under the hallway and additional air bricks fitted at the rate of one per metre.  

It should be noted that cast iron air bricks from Victorian and Edwardian periods were manufactured to varying standards and designs . Although their external dimensions were standardised the free air flow through the air brick varied widely with some providing very little air flow making them almost useless.

The "4 star" cast iron air brick design above is an example of a poor design - even brand new or cleaned out, this air brick at best could only achieve a free air flow of 1500mm2 as by design it has significantly more metal than holes. This is about 1/3 as efficient as the period example below and the two modern replacements which all achieve around 5000mm2.


Below we take a look at a standard designed Victorian cast iron air brick and compare its dimensions and specifications to a modern replacement.

period cast iron air brick

The type above, known as "12 Tees" by way of its "T" pattern of six along the top and 6 along the bottom has excellent free air flow and would have been used singularly or doubled or tripled to provide for larger vents as 9" x 6" or 9" x 9". It was predominantly used as sub floor ventilation in brick houses to vent below wooden floors to reduce damp and prevent rot (especially dry rot).

Seen below against two modern reproductions, it is clear to see although the patterns are different , the design remains principally the same the design.

The top air brick is a Windsor (item WIN3) vertical slotted and the bottom, a grid pattern (Item GRID3), both supplied by....

 "The Cast Iron Air Brick Company"

comparing cast iron air bricks

Photographed from the underside.........

cast iron air bricks

 Period Cast Iron Air Bricks and Modern Replacements

A Comparison
  item 32
Size 9" x 3" 8 1/2" x 3"
Weight 0.8KG 1.0KG
Depth of Wings 1 1/2" 2"
Thickness 1/8" 3/16"
Material cast iron cast iron
Free Air Flow 5,000mm 5,500mm
 Floor Vents
& Floor Grilles

Below - See the huge range of cast iron floor grilles and vents on the cast iron air brick company website,

Floor Grates are suitable for orangery's, churches and conservatories. 

Below - Hit and Miss cast iron air bricks allow controllable ventilation

Looking at these more closely, they were designed for use as controllable ventilation especially for use with solid fuel fires . When the fire was off they could be closed to cut down the draught and once the fire was lit they could be opened again to allow air flow and improve the "draw" of the fire.

The Victorian cast iron hit and miss air brick was designed with fairly close tolerances to allow the grille to shut of the air as much as possible but this has often led to many failing prematurely as they are prone to seizing. With this in mind, the modern replacements are visually similar and ideal replacements for house restorers but do not shut off the air completely as they have very loose actions which significantly prolong the life of the unit.

These hit and miss air bricks are suitable for installation as adjustable ventilation providing fresh air to inglenook fires, solid fuel fires and void spaces such as blocked off chimneys. They should never be used for fresh air provision for any gas appliances or where paraffin heaters are used.

hit and miss 9x3

Installing Cast Iron Air Bricks

for more details on installing cast iron air bricks go to    

Cast Iron Air bricks can be used as air inlets and exhaust outlets in the following situations :-

  • Suspended Floor Air Vents,

  • Tumble Dryer Outlets

  • Kitchen Extractors Outlets

  • Hob Extractor Outlets

  • Bathroom, WC and Laundry Extractor Outlets

  • Roof Space Vents

  • Room Ventilation for Gas, Solid Fuel and LPG Fires

  • Compartment/Room Ventilation for Gas and Oil fired boilers

  • Fresh Air Vents

  • Inglenook Inlet Vents


Cast Iron Air Bricks shown are supplied from
"The Cast Iron Air Brick Company"


Format for using our photographs/comments
Please add the following link to your website and email us to let us know you are using our material. thank you. 

"Information/Photographs supplied by "The Cast Iron Air Brick Company"

Down Farm, Brayford, Devon EX32 7QQ tel 01598 711999


Disclaimer- All the information supplied regarding the suitability of our cast iron air bricks for various ventilation scenarios shown on or given by any of our representatives is given in good faith and is for guidance only. A qualified architect, local building regulations officer and/or Corgi registered plumber if applicable should be consulted prior to installation if in doubt. In the case of installation on a listed building, permissions from the local authority should be sought from the conservation officer before any work is carried out, even to replace damaged items. The Cast Iron Air Brick Company  Cast Iron Air Bricks - Cast Iron Air Vents - Cast iron Vent Grilles  - Cast iron Grilles


We specialise in cast iron grilles and antique cast iron ware, metal and cast iron air brick replacement. We also have grill cast iron, cast iron air bricks and grates plus metal air vents, architectural vents and all cast iron air vents and cast iron air vents. Whilst our cast iron vent grills and cast iron air bricks are not Victorian or antique they are heavy duty reproductions which will replace or repair cast iron vents and grills. Brass vents are available in stock as hit and miss vents or hit and miss grilles. We also have floor vent grilles and vents in cast iron and brass.

Cast Iron Air Bricks

Cast Iron Air Bricks

Cast Iron Air Bricks

Cast Iron Air Bricks

Cast Iron Air Bricks

Cast Iron Air Bricks

Devon Yurts - Devon Self Catering - Cast Iron Air Bricks - Installing Cast Iron Air Bricks - Max Flow Cast Iron Air Bricks - Compare Cast Iron Air Bricks - Brass Vents