Air bricks & under floor ventilation

[3&33&27]

I have bought bungalow which was built in 1954 -The air bricks are concreted over- the previous owner stated this was done when it was cavity wall insulated approx 20yrs ago -
the surveyors report said they needed opening up to provide sub floor ventilation - I have drilled the holes out but it appears there is no air brick or opening in the inside cavity wall ? was it normal in the 1954 not to have "through " under floor ventilation , I am considering just smashing through the internal cavity wall to provide an air flow - any views please ?

[welsh brickie]

you will need to drill through both walls to allow air to flow into the floor cavity.Its best to install as many airbricks as you can.

[xavi99]

Are you sure it has a suspended timber floor which requires ventilation?

As far as I remember there was a period when cavity walls were provided with air bricks to vent the cavities although air bricks were also provided at higher level aswell.

Alternatively is the inner skin airbrick offset? Air bricks should generally be opposite to provide a through flow of air. If there are air bricks all around the bungalow could it be that some are just 'decorative' and that the adjacent elevation would have inner air bricks? (Hope that makes sense).

Air brick requirements are 1,500 mm2 per m run of wall or 500 mm2 per m2 of floor area, whichever is the greater.

Good luck, hth,

99

[3&33&27]

you will need to drill through both walls to allow air to flow into the floor cavity.Its best to install as many airbricks as you can.

Thanks - looks like thats the only way - unfort the cavity is full of insulation & i will have to take a few bricks out to clear cavity & try and get some kind of sleeve in .

[3&33&27]

Are you sure it has a suspended timber floor which requires ventilation?

As far as I remember there was a period when cavity walls were provided with air bricks to vent the cavities although air bricks were also provided at higher level aswell.

Alternatively is the inner skin airbrick offset? Air bricks should generally be opposite to provide a through flow of air. If there are air bricks all around the bungalow could it be that some are just 'decorative' and that the adjacent elevation would have inner air bricks? (Hope that makes sense).

Air brick requirements are 1,500 mm2 per m run of wall or 500 mm2 per m2 of floor area, whichever is the greater.

Good luck, hth,
Thanks for that - yep def susp floor & internal airbrick not there ! Just gona have to smash through .

99

[welsh brickie]

[quote="3&33&27"][quote="welsh brickie"]you will need to drill through both walls to allow air to flow into the floor cavity.Its best to install as many airbricks as you can.[/quote]
Thanks - looks like thats the only way - unfort the cavity is full of insulation & i will have to take a few bricks out to clear cavity & try and get some kind of sleeve in .[/quote]


you can buy clay sleeves for the airbricks either 9x3 inch or 9x6 inch

[3&33&27]

Thanks -where can you buy the clay sleeves ? can only find plastic telescope type

[welsh brickie]

usually the big named builders merchants stock them jewsons,travis perkins etc

[3&33&27]

Thanks will try them & let u kno how i get on !