When cleaning walls with TSP before painting, what is the correct cleaning direction?

Cleaning walls with trisodium phosphate (TSP) before painting is essential for ensuring good paint adhesion and a smooth finish. The correct cleaning direction, from ceiling to floor, is important for several reasons.

When you clean from the ceiling downwards, any grime, dust, or debris that falls during the process will land on the lower portions of the wall, which are subsequently cleaned afterward. This technique prevents the recontamination of already cleaned areas, particularly those closer to the floor. Additionally, cleaning downwards can help avoid streaks that may occur if dirt and debris are pushed upward.

Using this method ensures an even clean and prepares the wall adequately for painting, resulting in a more professional-looking finished product.