Dear Home Ec 101,
My living room desperately needs to be painted and I’ve rounded up a few friends willing to help sell their time for beer and pizza. I really want to do this right, is it true that I have to wash the walls before I paint?
Look at it this way, washing the walls can save you money and time in this project. Seriously. Anytime you cook, open the window, spray hair spray, etc particles that can adhere to your walls, do. Over time this creates a thin, mostly invisible but greasy layer of dirt and dust on your walls. This layer of funk isn’t evenly distributed, making it difficult to evenly apply your new coat of paint.
Any degreaser will do, but if you want the job to go quickly with little elbow grease, check out TSP or Trisodium Phosphate. This chemical, when mixed with water has a high enough pH to saponify grease. This simply means that it turns the grease on your walls into soap. TSP used to be included in both laundry and dishwasher detergent until it was found that algae really loved all the extra phosphorous in the water supply. Since then it has been phased out of detergents, but it’s still appropriate for small applications.
TSP is not your, gee-the-walls-look-a-bit-dirty-but-I’m-not-going-to-paint wall wash. Trisodium Phosphate etches or chemically scratches the paint surface while it strips away the grease. If you’re getting ready to apply a fresh coat of paint, this is pure win as it gives the new paint better adherence.
I strongly urge you to read and follow the directions and safety precautions. While the highly alkaline nature of TSP makes it fabulous for stripping grease off of walls, it also can cause chemical burns if it gets on your skin. Keep it in perspective, chlorine bleach also causes chemical burns when used inappropriately.
You should be able to find TSP at home-improvement stores.
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