A cinder block wall requires a specific grade of paint in order for a fresh paint job to be effective and long lasting. The cinder block wall should also be primed before painting to ensure an even and stronger finish. Most cinder block walls need an exterior paint, but the paint used on a cinder block wall indoors will be different.
To ensure a properly painted surface, the cinder blocks must be prepared correctly so that the paint adheres to the surface evenly. If the surface has been painted before, try and remove as much peeling paint as possible before priming. Take this time to use a pre-mixed mortar patch to repair any significant cracks or portions of missing cinder block. Allow enough time for the mortar to dry before moving on to the next step.
Pressure wash the wall first and allow it to dry. Getting ride of any dirt or dust on the blocks will help the primer and the paint adhere better to the concrete blocks. The cinder blocks are very porous, and the use of an acrylic primer will fill the pores of the wall and give you a smoother finish. Apply the primer generously with a thick nap paint roller. Allow time to dry as per manufacturer's guidelines and then add a second coat.
Exterior Cinder Blocks
After applying two coats of primer, it's time to choose the type of paint you want to use on an exterior cinder block wall. This paint needs to be durable and capable of standing up to elements such as heat, moisture and precipitation. Use either an elastomeric or acrylic paint as the final coat. Apply at least two coats of paint to ensure adequate coverage, waiting in between coats for the paint to dry as advised by the manufacturer. Choose a roller with a thick nap and preferably lambs wool material for best coverage. Cheaper rollers tend to become compressed and difficult to work with on cinder blocks.
Interior block walls are usually of a smoother texture and much easier to paint. The smooth-sided block requires about half the amount of paint as a rough exterior cinder block. The primer should still be acrylic, but the final coat can vary from latex to acrylic or elastometric. Sheen can vary as well from a flat finish to a high gloss, depending on the decor and design of the room. The paint can be spray applied instead of rolled.