how wide are extension footings

the standard minimum size should be 600mm wide for a standard width cavity wall of 300mm. (100mm brickwork, 100mm cavity, then 100mm blockwork). there should be a minimum of 150mm of concrete at either sides of the walls to = 600mm in total but all jobs and ground conditions vary, so your best advice is to check with your local building control which can be contacted through your local council.

the standard footing width with a 100mm caverty wall will be 450mm, make sure to consult plans because this may vary due to ground condition and type of footing all info should be on a comprihensive set of plans,

600mm is the expected width and one mtr minimum depth

Typically 450mm wide. That will allow for, Brickwork - 100mm cavity - Blockwork And depth just depends on ground condition, 600mm would be good enough if you hit good clay..

the best way to find these details out are to give the local building control officer a call as they will be more than helpful for you

Normally 600mm wide.

Normally 450mm but its dependant on ground conditions. Rick

they are generally 600mm wide but check with you Building Control Officer

Your footings will need to be 1metre deep & 600mm wide.Unless you have any issues,Your building inspector will advise you on this.

600MM