Help with drilling near a lintel

[paulmarkj]

10 years ago, a supporting wall was knocked down leaving a 1.7m hole. I don't know what kind of lintel was used. I want to hang sliding doors in that hole, but I am not sure how to proceed.

If I hang the doors from the inside, I have to drill up into the lintel, possible drilling into an RSJ.

If I use sliding door gear on the side of the wall, I drill horizontally, but not sure what I drill into. I'll try to draw a diagram:

RSJ
--------
|
| <---- drill this way
|
--------

^
| drill this way
|

or could another type of lintel have been used.

The wall is solid brick (1920s build).

 

[noseall]

At 1.7m span, it may be a PCC (concrete) lintel or it could even be wood.

The bigger question is - why sliding doors? They are a right pain to fit and have few redeeming features.