- For variation on the top surface, I add gy021.jpg (Total Texture V3) and used a layer mask to subtle the edge of the texture image.


- To made it more aged, I add gy010.jpg (Total Texture v3) with overlay mode and place it to where the arrow was pointed.


- Add a dirt from tile04heavy003.jpg (Total Texture v5) with overlay mode.


- Finally I placed a bri017.jpg (Total Texture v2) brick. the same brick layer was copy above on the same position, but the above brick layer using hardlight mode with 59 value of opacity to give a strong color, while the below one still using a normal mode.


- Add a final touch for the building edge, paint a dirt with a small size spatter type of brush.



Texture for the chimney, result from gy010.jpg (Total Texture v3) plus br005 (Total Texture v3) with multiply mode..