I have appended an old house building to a scene that was made using blender engine, but now in a cycles scene. I have attempted to add a brick texture to the house but it won't show. I am new to cycles and ideally would like to use the roof texture imbedded in the file but am happy with just adding the brick texture for now. Any help would be appreciated. If it is possible to add the roof texture, I don't know how to add multiple images to separate parts of an object in cycles.
First you haven't assigned your material to your walls, so, in Edit mode, select the walls, then select your brick material in the material list, and click Assign.
Now you still can't see bricks because your current material is not good.
You've plugged your Brick Texture node in the Factor of a Mix Shader, it could work like that but:
It's not the colors that will be taken into account in the Factor of your Mix Shader socket but the values, the more your color will be white the more it will let the bottom node of your mixed nodes prevail, that's why in general we plug only black, white and grey values in this socket. In your case your values are too close, so maybe only use black and white to make it clear and simple.
Beside that, in your Mix Shader sockets, you've plugged 2 Principled BSDF node that have pretty close Base Colors, so it won't allow you to see any brick precisely, maybe choose more distinct reds.
At the end it could give something like that: