Fiting uv map to image I want to create a wall for a castle .Lets say that the image i want to fit to that wall is 4x4 (meters). And my mesh is 1.8(lenght)x5.3(height) [also in meters].

I assumed that the uv area (i dont know what it is called , the one i circled) 
Is where the image is , which is 4x4 as mentioned.

So i smart unrapped it (stretch to uv bounds and correct aspect)

I also assumed that my uv unwrap is also 4v4 since my image fiting there was 4x4)
Pressed R: 90 ,  (for rotation) then S: .25 (to scale my object bounds to 1x1)
Then S: x 1.8 and S: y 5.3 to fit original size of mesh to image. 
After that i did the same thing to another wall size 2.25x2.9 (meters) with the same picture and the result was that they had diffrent size of bricks. 

Pls i would apprieciate any help / tip . im kinda new . (the project is to exported to unity and im telling that cause of the nodes) . THanks in advance

*What im trying to say is , how to fit the same image to driffrent wall sizes, and keep image-brick size the same.
what's up fellow beginner! Did you set the rotation and scale before unwrapping? In Object mode, select the Object and press Ctrl+A. Select Apply > Rotation &amp; Scale. This is a helpful tip if you find your uv maps come out with weird aspect ratios.