Currently preparing an area in our garden to lay a paved patio area and pergola (the latter being provided by a professional).
My wife and I need to build a supporting wall around the sides and at the top side (see the photos below). Essentially, the supporting wall needs to be parallel with the brick wall (Which is actually our garage)
What my wife and I cannot figure out – and we're not entirely certain that this is a 'common issue' – is how to get a straight line with a wall that is 'higher up' than our supporting wall.
Being that we cant simply butt up our builders square, because the wall underneath the brick wall isn't straight by any means (and we doubt we can get it straight/want to!) – how do we plan to build a parallel, straight wall?
Other photos for reference:
https://drive.google.com/open?id=1n0uZGcJKewga6NwDj0t0hq0YT7brKBjd
https://drive.google.com/open?id=1a4cKgta-jaHFm3Nj2UcmzEQPjZK8fy-A
Best Answer
I'd set a couple of 2x4 stakes in the patio area as an offset line, parallel to the brick but out of the way of the new wall. This will allow you to set your final lines appropriately.
Establish your first parallel line with a level
Create a perpendicular line using the 3:4:5 technique
From there you can take measurements to parallel for your actual wall positions. The drylines can stay in place during wall construction for reference.