Prepping Cinder Blocks for a Fresh Coat of Spray Paint

Adding a fresh coat of spray paint is a simple way to update the look of drab cinder blocks. With the right prep work and painting technique, you can easily transform plain cinder blocks into an eye-catching feature. The key is using outdoor-friendly spray paint formulated specifically for masonry that will adhere properly to the concrete blocks' porous surface.

Since cinder blocks have a rough, absorbent texture unlike other surfaces, not all types of spray paint work well. The prep work is also unique to ensure the paint bonds tightly. By selecting heavy-duty spray paint for cinder blocks and thoroughly preparing them first, you'll achieve beautiful, long-lasting results.

Choosing Spray Paint Made for Cinder Blocks

The first step is choosing a high-quality spray paint variety designed with exterior cinder block projects in mind. The right formula and finish will allow the paint to grip the textured concrete surface and withstand outdoor conditions over time.

Opt for Durable Oil or Latex Paint

Oil-based spray paints create a glossy, protective finish that penetrates deeply for exceptional adhesion and durability. Latex paints offer more flexibility to resist cracking and provide good coverage as well. Both oil and latex work well if buying paint made for masonry.

Avoid standard spray paints meant for metal or wood. While less expensive, they lack the binding resins to stick to cinder blocks even using primer. Specially engineered masonry paint contains ingredients to harden fully and seal porous concrete.

Get Paint Designed for Concrete

Verify the spray paint is approved for use specifically on concrete cinder blocks rather than just general masonry surfaces. Paint labeled for concrete, cement, stucco, brick and the like will bond best. If unconfirmed, test paint adhesion on an inconspicuous block first.

Masonry spray paint in a flat, matte, or satin low sheen finish works nicely to downplay imperfections. Gloss finishes make defects obvious. Textured spray paint is another cinder block-friendly option adding dimension.

Factor in Color and Coverage Ability

Darker paint colors or drastic color changes may require extra coats for opacity on cinder blocks, as will block walls with existing paint or sealer. Buying high pigment, high hiding spray paint ensures sufficient coverage. If changing block color significantly or needing to hide graffiti, consider applying tinted primer first so less paint is needed.

Properly Prep Blocks Before Spraying

Prepping cinder blocks prior to spray painting is equally as vital as choosing the right paint. Thoroughly cleaning and lightly sanding the blocks allows for maximum paint adhesion. Failing to prep can cause the paint to chip, peel, or rub off easily. Prep work also removes built-up dirt and unsightly stains.

Clean Blocks Completely First

Start by spraying blocks with water and scrubbing thoroughly using a stiff masonry brush to loosen visible dirt and debris. Pay extra attention to oily areas or mildew growth. Let the blocks dry fully for at least 24 hours before continuing.

If needed, apply concrete degreaser solution or liquid mortar cleaner to cut through problem stains after initial cleaning. Rinse and let dry fully before proceeding. Proper cleaning is vital for paint bonding successfully.

Repair Any Cracks and Holes

Inspect blocks closely and use cement patching compound to fill small holes or cracks for a smooth finish. Repair crumbling joints between blocks as well using patching cement before painting. Allow patching materials to cure fully per manufacturer instructions.

Roughen Surface Texture With Light Sanding

Use 100-150 grit sandpaper attached to a hand sander to lightly scuff up the entire cinder block surface. This etches fine grooves for the spray paint to cling to. Avoid completely removing sharp edges or details. Just focus on roughing up the surface.

Wipe away all sanding dust using a tack cloth. If any debris remains under the paint, you risk premature peeling and chipping down the road.

Apply Primer or Bonding Solution

Applying specialty masonry primer before painting allows for superior adhesion and creates a uniform surface for the topcoat. Use tinted primer matched to paint color for extra coverage. Alternatively, use concrete etching solution following product guidelines.

Let the primer or etching fully dry overnight. Then a single coat of primer and one or two paint coats work fine for most small projects. Larger block walls benefit from two separate primer coats.

Spray Painting Cinder Blocks

Once prepped, start spray painting cinder blocks using proper technique for flawless results. Work methodically applying light coats, allowing adequate drying time between each one. Rushing the painting process risks paint runs, splatters and uneven coverage.

Work in a Well-Ventilated Area

When spray painting concrete blocks or any project, be sure the area has ample airflow to vent paint fumes. If spray painting indoors, open doors and windows and run fans to circulate fresh air. If no ventilation, use an organic vapor respirator when painting.

Vigorously Shake the Spray Paint Can

Shake the spray paint vigorously for at least one full minute before starting. This thoroughly mixes the paint pigments and binding ingredients for smooth flow and application.

Periodically shake the can every few minutes while painting to maintain consistency. Insufficient shaking leads to spraying uneven, splattery paint.

Hold Can 6 to 10 Inches from Surface

Position nozzle 6 to 10 inches away from blocks, adjusting as needed. Starting too close risks paint dripping. Begin moving can left to right smoothly keeping your motion steady to prevent uneven coat thickness. Overlap strokes blending each pass.

For wider sections, use spray paint specifically designed to spray at any angle, even upside down, for easy coverage without arm fatigue.

Apply Thin, Even Coats of Masonry Paint

Mist on the first coat very lightly not soaking the blocks fully. Thick coats won't bond well. Allow 10 to 30 minutes of drying time depending on humidity before applying the second coat. The concrete blocks should feel dry to touch without tackiness.

The second coat of spray paint should provide full opaque coverage following similar spray pattern motions. Apply two to three coats total, allowing each to dry thoroughly between coats for professional looking, long-lasting results.

Achieving Impeccable Paint Results

With the right spray paint products, diligent surface prep and proper spray technique, even novices can achieve flawless, pro-quality painted cinder blocks. Here are a few extra pointers for perfecting the job.

Use Painters Tape for Ultra Crisp Edges

Run low tack painters tape along any edges or boundaries near the blocks you don't want catching stray paint. Remove the tape immediately after the final coat before the paint dries. The tape leaves an ultra sharp defined edge.

Try Painting Accessories for Tricky Areas

For adding paint to hard-to-reach spots or corners, use spray paint handles for improved control and less hand fatigue. Small spray paint shields with cutouts also direct overspray away from nearby surfaces.

Consider attaching a paint brush to the spray nozzle to manually paint corners or details too narrow for spraying. This ensures full paint coverage on intricate block designs.

Let Paint Dry Thoroughly Between Coats

Waiting the specified recoat drying times between layers allows each coat to cure evenly with no drips or runs. Rushing the job risks trapping moisture between coats resulting in bubbling or peeling later on. Be patient for best quality results.

Once painted blocks have dried completely per can directions, apply two coats of clear sealer for extra protection and longevity. Use exterior grade acrylic or urethane sealer formulated for masonry and concrete. Adding sealer prevents premature paint fading.