Hi,
so I made a quick test with the textures you linked,
for me it's working good, but at some point I taught something was wrong,
and in fact I exported a room with bad normals :
- check that your normals are not flipped in blender (use "flip" button or "calculate outside" to be sure)
- enable the "smooth" shading in blender to visualize the real normals (don't use the flat mode).
- and then be sure you are applying the "edge split" modifier to have clean smoothing groups.
It can also be that your UV mapping is reversed in x or y for the floor.
Tell me if it works, and I'll investigate more on this topic.