double skin garage lintel extension

[andy0]

hi, hopefully someone knows what i should do.
im building a double garage with the idea that one day it might be converted to habitable space, so im doing a brick outside, block inside cavity wall. its a detatched double. im stuck on the front of the garage. it has 2 single garage doors, with a pier between, supporting a gable. what lintel do i use that will be 2.5m wide and span the cavity?

thanks for your help

 

[hotrod]

Hi Andy, how wide is the cavity? Also how are you insulating the cavity and are your LABC involved to ensure you comply with appropriate Building Regulations?