Creating doorway from house into a garage.

[CortinaV8]

Just after a bit of advice really.

I'm considering putting an opening into my garage from the hallway.

I understand there needs to be a difference in floor heights between the two rooms, I think this should be ok, however a raised threshold isnt an issue.

I know I will need a fire rated door, I think the regulation is 30mins?

The bit i am unsure on really is the lintels, I assume due to the span and the standard nature of the job that no structural calculations would be needed for a bog standard doorway and the lintels could be bought off the shelf? Likewise cavity closers would be needed? the house does have cavity walls but the gap between is fairly small, maybe 5cm or so.

Just after a bit of useful advice before I approach building control really.

 

[Craig600]

How much weight do you have above the potential door?
You shouldnt really guess at what size lintel to use this is the job for a structural engineer if it is load bearing.
Last time i checked the regs stated an hour burning time but they change all the time.

You will need 50mm cavity closers

 

[CortinaV8]

The first floor and roof is above, the roof bears onto the wallplate at the top of the wall, other than that nothing, the floor joists all run in the opposite direction.