I think he is talking about the wrong triangles shown on the ground, this is the fixed link to the image:


This may have different causes, all belonging to the model:
- z-fighting between close poligons;
- wrong faces orientation and backface culling turned on;
- wrong vertex normals.

I think you are using a furniture to represent the ground. Try instead to use a room, apply the texture and scale it to match the room size.
If you want to use a furniture, try with a standard cube, scale it properly and apply the texture on the upper face.