How to clean garage walls before painting If you’re starting to prep your garage for a paint job.
You should know that the best way to prepare your walls before painting depends on the current condition of your walls and whether you plan on repainting them or covering them with paneling or drywall.
If the walls are dirty, however, you might need to give them an extra-thorough cleaning before using paint, no matter what kind of finishing product you plan on using over them.
Follow these steps to clean your garage walls properly before painting them so that your DIY project looks great when it’s done.
How to clean garage walls before painting
Step 1: Equipment
you will need a wire brush, a nail brush, and a shovel. You will also need an industrial wet/dry vacuum (get 2 of them if you have a large area).
Most companies rent these by the day or week. You’ll also need strong air ventilators like leaf blowers, electric fans, and air movers to dry up any wet spots on your wall.
An exhaust fan works great for removing dust from sanding.
Lastly, you’ll need spray paint: it’s important that it has excellent coverage and dries in 8 hours or less.
I prefer Sherwin Williams Super Paint for home improvement projects since it is guaranteed 15 years of wear indoors and outdoors with no prep work required.
Step 2: Spray on Grease Remover
Use a spray bottle filled with a grease remover solution and give your garage walls a good scrubbing.
Most types of oil or garage paint ideas are easier to remove with a chemical solvent such as methylene chloride, acetone, or xylene than they are with soap and water alone.
You can purchase these solvents at hardware stores for about $5 per liter; keep in mind that one liter should be enough to clean roughly 80 square feet (just over 8 square meters) of wall space.
Depending on how dirty your walls are, you may have to soak them down several times before they’re ready for painting.
Make sure you cover everything in your garage and open up some windows; even just 30 minutes of ventilation can make cleaning much more pleasant.
Step 3: Scrub with Water
Although you don’t need to scrub hard, you do need to scrub thoroughly.
If your garage walls are dirty, then it’s probably due to grime that has accumulated over time and needs a good cleaning.
Start by wetting down each wall with water. Use a push broom or a mop to cover larger areas.
Then, use either an all-purpose cleaner or an alkaline degreaser depending on what type of dirt is ingrained in your walls.
As you clean with either of these products, keep in mind that overly aggressive scrubbing can damage the paint.
Step 4: Remove Residue and Streaks
Use a paint scraper, which you can purchase at most hardware stores, and scrape off any stubborn residue from your wall.
Next, use a utility knife to trim away any peel-and-stick remnants. Be sure not to nick or gouge your freshly painted walls with your knife’s sharp edge if you do, you’ll have more work ahead of you.
Removing every last trace of old stickers will ensure that they don’t damage your new paint job when they start peeling.
Step 5: Use Paint Prep
Paint prep is a paint additive, designed to clean and smooth rough walls before painting. The truth is, it’s only effective if you use it correctly and most DIYers don’t.
If you’re planning on your garage wall paint, follow these steps:
1) Use a wire brush to remove any loose debris from your walls;
2) Apply a thin layer of paint prep;
3) Let dry for 24 hours;
4) Remove with water and soap;
5) Repeat as necessary until the wall is clean.
It may seem like overkill, but when done right, it will help prevent peeling in the future.
Step 6: Cover Wall with Plastic
Covering your walls before painting is a must. Not only will plastic protect them from over-spray, but it will also keep paint out of your hair, off your skin, and pretty much anywhere else you don’t want it.
Have wallpaper on your garage walls? Use duct tape instead of plastic. A few layers of duct tape should do just fine!
Step 7. Paint Over
Once your walls are clean, it’s time to paint. If you have any oil-based paint already on your walls (if you previously painted over the wallboard, for example), it’s a good idea to wash that down first with mineral spirits or TSP (totally safe products used by professional painters and available at most hardware stores).
Make sure all surfaces are well covered; let them dry. Then sand smooth before painting.