Brick step covering gas pipe

[optionclick]

I have a gas pipe running along an external wall and it passes in front of a raised doorway.
Currently there's a temporary step in the form of a palette but I want to build a more permanent brick version.

There is a loose fitting PVC sleeve over the portion of the pipe where it passes the doorway.

My question is how to build the step in order to retain any space/access to the pipe - I'm guessing I can't /shouldn't embed it in the mortar, or will the PVC sleeve provide enough of a gap?

Pic below for clarity

Thanks in advance

 

[^woody^]

Split some wider waste pipe or downpipe and sleeve it. The ends should be left open.