This gives a minimum open area per meter run of wall of 600mm.
Beam and block floor ventilation.
For vents at ends of beams just position between the beam ends and avoid fiddly lintel detail.
Beam and block flooring demonstrates good noise reduction and fire resisting properties and is also suitable to host underfloor heating systems.
Roughly though one vent per 2 lin m is more than enough.
The design for the floor will detail the sqmm of ventillation per sqm of floor and lin m of wall.
In areas where there might be landfill gas or methane contamination the minimum area of opening is.
This also applies to any internal sleeper walls.
Air bricks set at or close to ground level may ood and allow rainwater to enter the under oor void.
Adequate cross ventilation to meet nhbc standards and building regulations.
Air bricks should be kept clear of obstructions that could reduce or block the required air ow.
A minimum ventilation void of 150mm should be provided below the underside of precast concrete and timber suspended floors.
On shrinkable soil where heave could take place a larger void is required to allow for movement according to the volume change potential.
Also the sleeper walls should be built as honeycomb to allow cross ventillation.
Ventilate the underfloor space by providing ventilation in two opposing external walls.