Building utilities on a wall corner

I am building a rather large prison all at once, and have run into a problem. I built cell blocks en masse, and then built the utilities. This is causing this to happen:

The builders cannot reach the pipe to build it because of walls, and end up deleting the job.

While I could remove a wall to let the Workers in to every pipe, that might take 30 minutes+ and would be expensive. Is there any way to force a Worker to build on these corners?

This was identified as a bug (#0005061) and is fixed by updating to Update 7.

I struggled with this for a long time, and in the end, no, there's no other way to force them, because they cannot physically get to where they need to get. For now, destroy the wall pieces that you need, then rebuild them.

Consider next time, figuring out where your toilets/plumbing items will be, and lay the pipes before building any of the walls. (The planning tool is extremely useful for this) and it will avoid the situation entirely.