Could be glitchy this one. This popped for me after upgrading my timber and concrete factories once. I hadn't even built the brick factory at this point.
Get a work crew into each factory to create resources. Once both factory's are full (50 of each type) the achievement should pop.
If your factories are built next to tenants' houses, deliver then double glazing, this will prevent complaints. Also creating another forman and supplying him with some workers to create another work crew will speed things up if you are wanting to build whilst getting your resources together.