Stain under windows. After winter, the bricks under windows have white powder (efflorescence) as shown on the photo. When I bought the house last year and some contracts told me it was because the window seals had a lot cracks and the water enter the wall through the cracks. So, I redo all window caulking last year, but the problems are still not solved. Now some contracts told me I have to repoint the brick joints under the windows to solve this problems. I would like to get your opinions. Thanks.