3D Environment: Idea gone wrong. Wood Wall

I had an idea of making a finished wood plank wall so i could just place it into the scene and i would not have to repeat the planks and make the game scene less expensive.
However this did not work, once i had made the high poly there was no way for me to match to the original low poly because it had changed to much and i could not create a low poly out of it because it was to thin.
Another problem was in my design both the sides of the house are not the same size as the house has been left and start to bend and rot so having one wall would mean all the sides would be the same size which is not what i want.