3Ds Max - My house

I have recently been working on my house in 3Ds Max: here's what it looks like so far:

I looks like its going ok but I am having trouble with some of the textures.

 This is what the texture should look like, even after it is rendered...

...But all get is this. Every time it is rendered, I get ant-sized bricks on the texture. No matter what changes are apllied, the result is always the same and I'm not sure what the problem is.

If this can't be fixed, I shall restart from an previous save.