Access door to garage height above ground

[Macca80]

I'm looking to add a composite door to provide alternative access to my garage. Is there a minimum height above ground level that's recommended? I would like to have a gap of 80mm, then the cill and door. There is a soak away round the garage already. Are there any potential issues with this?

 

[motorbiking]

Is this connecting to your house? There is supposed to be a "flammable liquids/gases" barrier of 10cm to stop say a petrol leak flowing in to the house.

 

[Macca80]

No it's an external door not connected to the house

 

[noseall]

I'm looking to add a composite door to provide alternative access to my garage. Is there a minimum height above ground level that's recommended?

Surely the personnel door needs to be at garage floor level? Equally, there is nowt wrong with dropping the threshold down a wee bit (altering sub DPC masonry to suit) if losing some of the bulky door threshold is what you are trying to achieve, as long as the door swinging path is not compromised. Height above ground will be largely irrelevant for a plastic door.