The process of painting cinder block walls in a basement this is for unpainted blocks or if you want to repaint your cinder block walls.
When you have a basement, you will either have a concrete foundation or cinder block foundation. By painting the walls or foundation, you increase the appeal of the space, but also it improves the moisture control from the wall. Concrete is a porous material that can absorb water from the ground and transfer through the foundation. By using a waterproofing paint, you control some of this transfer from happening. Let me share how to paint cinder block walls in a basement or concrete to help you waterproof your basement.
I am sharing with a cinder block foundation because this is the type of walls we have in our basement, but again this does work for a concrete wall too. Also, our walls were painted before, but they were starting to flake, and we wanted to make sure they were waterproofed before finishing the space.
Disclosure: This post contains some affiliate links or referral links for your convenience. It is a way for this site to earn advertising commissions by advertising or linking to certain products and/or services, click here to read my full disclosure policy.
STEP 1 – How to prepare a cinder block wall for painting
With every project, there is always prep work, and this is an essential step to give you the finish you want. But before starting, put on my mask and glasses, safety first!
Start by scraping off all dirt, loose grit in cracks, and if your repainting, the old flaking paint with a painter’s tool and a wire brush. Use a shop-vac to vacuum up the scraped off material.
After, you need to patch any holes or cracks where water could seep in with hydraulic cement. Follow the instructions for the hydraulic cement, or if you want some extra help, be sure to visit my tutorial on how to waterproof cracks in a foundation.
Once the cement has dried, its time to clean the walls. Use a shop-vac again to vacuum up any loose materials.
Make sure to remove Efflorescence (a white, powdery, crystal-like deposit) by using Drylok Etch or muriatic acid to clean the area. Be sure to use it according to the manufacturer’s directions.
Then using a mild detergent, clean the walls to remove any extra dirt or residue.
Allow the wall to dry for at least 24 hours before moving onto the next step.
STEP 2 – Paint cinder block with paint
Now you’re ready for paint! You could be wondering what kind of paint you use on a cinder block because the type of paint you use will make a difference in waterproofing your walls. I have used two different types and I would recommend using Drylok.
SIDE NOTE: Drylok is tint-able, so you can color it!
Apply the paint according to the manufacturer’s instructions, but here are some basic guidelines.
Stir the paint thoroughly before and during painting.
TIP: Use a drop cloth to protect the floor from paint.
Apply the first coat of paint by cutting in around the edges of the wall with a paintbrush plus between each joint of the cinder block. You want to paint the joints with a paintbrush because it is challenging to paint with a roller, and every pore of the cinder block needs to be painted.
SIDE NOTE: You could paint the whole wall with a paintbrush if you are worried about filling in each pore.
Next, use a high-quality 1/2″ to 3/4″ nap roller to paint the rest of the wall with paint. Again you want to fill every pore and void on the wall’s surface with paint, so make sure this is happening as you roll on the paint.
Let the paint dry according to its instructions. Then you can apply a second coat the same way as the first coat. Take some extra time to make sure you are covering any pores you missed with the first coat.
Allow the second coat to dry then confirm that the pores are each painted. If you happened to miss some, use a paintbrush to cover these areas, then let it dry.
And that’s how you can paint cinder block interior walls.
Interested in more