How do I make these PBR roof tiles not flat? I'm trying to model my house using Blender.  I'm stuck with trying to get a realistic tiled roof.  When I follow a tutorial online, I think I'm doing all the correct steps in the Shading area, but it still looks flat in the the Cycles render.
This is the texture I'm trying to use https://texturehaven.com/tex/?t=roof_09
(although I will need to find a better one for my final design!).
But it looks totally flat:

What might I be doing wrong?
Here is my .blend file:  http://files.staging.x-rm.com/nick/house5b.zip
There are 2 different things:

For your normal setup, you need to switch the Image Texture to Non-Color as Christopher says, and the Normal Map to the default Tangent Space (I don't know what's Object Space though):



For your Displacement node. Again switch to Non-Color. Also, you've plugged this node into the Displacement socket of the Output, and you've chosen Surface &gt; Displacement &gt; Displacement &amp; Bump in the material Settings, which means that you want the bump effect but you also want a real displacement effect. The displacement itself acts on real geometry, it can only affect an object that is subidivided enough, otherwise nothing happens. Your roof is just made of one face, so it can't be displaced for real. Therefore for the moment only the bump effect happens (which cumulates with the normal effect, which is ok if this is what you want but it may be redundant. And it will also be redundant with the real displacement):


As you can see here is what it gives if I subdivise enough a plane and give it your setup (I had to decrease the Displacement strength though), not sure the height map is good though, giving the result: