The ceiling of the basement & the floor of the main level are a series of 6 planes (5m x 5m). Each of those 6 planes consists of 4 separate planes (2 normals firing up & 2 down) to make a complete floor/ceiling for our building.
I found a wood floor texture on Mayang that I liked that had gaps between the planks, so I took it into Photoshop and selected all the space between the planks and rendered them black, then I got some help in making an alpha map to make the gaps transparent and loaded all that into 3D Studio Max, and since the texture was a 512 x 512 and the plane was a 5m x 5m square, the UVs didn't really need to be messed with ... just assemble, attach & group together. The render seen here is the resulting view from the basement looking toward the front door/window that you can somewhat see.
If I feel nutty I may use the Shift + Click & Drag to to add geometry to the planes and give the planks more depth, but for now ... done & done, moving on.