As per post about acrow props, i need to put a doorway from kitchen into garage. It is a single block wall, load bearing. I have a 1200 box lintel. I know i should really put a fire door frame in. Does anyone know the external sizes so i can make the hole big enough.

I know it would be easier to just buy one first, but i work away and have very little time at home, so just in case i struggle to get to the builders merchants when they are open it would be good to have the size as a contingency.

My standard internal door frames are 880mm wide. Im guessing a fire door frame has thicker timber so likely to be 900 wide.

Im also wondering what depths of opening they suit. Block must be 100mm. Plus 12mm board and dab on inside. Then there is 50mm jab light and plasterboard on the garage side, so probs 190mm total.

Eventually the access will be to create a 6' deep utility room so i will be putting a new stud wall up with fireproof plasterboard etc.


Thanks in advance,
Darren.