Widening nibs under concreted lintel?

[dilalio]

Terraced house with internal porch to front door. Facade of house has entry-way to internal porch as opening (no door) with concrete lintel supporting opening. There are nibs to left and right of opening which widens out, inside internal porch, with 4ft travel to front door. In summary, the front of the house is a complete solid wall with a lobby behind, gaining access to the front door!

My question is...
I have to widen the opening in the front facade, i.e. widen the gap between the nibs, to allow access for a wheelchair, self-propelled by the user.

This would involve more than just removing the pebble-dashing that currently covers the brickwork.

Any widening of this opening, involving cutting away brickwork, would leave the lintel above with less of an overlap, onto supporting brickwork.

However, the opening is quite tall and, rather than replacing the lintel with a wider one, I am considering spreading the load with a corbelling solution, using tiles or slate to bring the opening back in at the top to catch the lintel!

Does this sound like a viable plan?
Can anyone point me to a reference site which may provide some technical data?

Many thanks,
deano.

 

[Alastairreid]

corbeling using slates or tiles would not give enough support for a lintel!
you should install a longer lintel to do it properly.