How to Paint Masonry and Concrete Surfaces
A new paint job will bring new life to an exterior masonry wall, brickwork, a basement or garage floor and the overall appearance greatly improved if the work is carried out correctly and the appropriate paint for the job is used.
Clean the surfaces
For a good paint finish, preparation is absolutely vital. If possible, power-wash the surface to remove old flaking paint etc. Also, if mould or algae are in evidence then add some bleach or mildewcide to the water. If you are working indoors or the use of a power-washer is impractical, then us a scraper and wire brush to remove old paint.
After old flaking paint has been removed, ensure surfaces are clean and dry. Grease or oil on the surface will bleed through the new paint, interfering with the longevity of the paint and cause it to discolour. Apply TSP, to clean the surfaces before applying paint. Scrub well into the masonry or concrete surface to ensure that paint will adhere.
Repair any defects
After surfaces are clean, use a ready mix concrete patch to make repairs. The concrete manufacturer will normally make recommendations on drying time and tell you when the surface can safely be painted.
Choose your paint depending on where the paint is going to be applied. It could be the interior of a garage or an exterior wall for example. Some paints are even specifically created for floors, and additives can be used to provide more texture and grip. The experts at The Paint Shed are happy to provide advice and suggestions to ensure that you choose the most appropriate paint for the job.
At the same time as ordering your paint you should also consider if you require mineral spirits or paint thinner to clean your brushes or spillage.
Sealing and priming
Most masonry surfaces require to be sealed and primed prior to painting. The sealers stop moisture from seeping through the concrete or masonry. This is most likely to occur in basements. You can check if your basement has been already sealed by taping four sides of a square of plastic kitchen wrap onto the surface of the floor and leave for 24 hours or so. If the floor has not been sealed, water will have condensed under the plastic wrap due to evaporation up through the concrete. It's best to use a quality masonry sealer with a separate primer that complements it. The process of sealing and priming will build a strong, water-resistant foundation for the final painting.
Only start applying the paint after your sealer and primer coats have completely dried out. It’s preferable to use a brush for the detail work around windows and trim etc. A brush is also better for cutting-in between the walls and floor. The remainder of the painting can be done using a roller. Check with the manufacturer's recommendations as to what size nap is appropriate. Most likely it will be ¾-inch or 1-inch nap. Buy a minimum of three roller covers – for the sealer, the primer and the paint.
It’s better to apply several thin coats, rather than one thick coat, as paint creates a harder surface when thin coats are laid on top of each other. Paint dries (or cures) to different thicknesses, depending on its sheen and chemistry. The length of this process depends on the thickness of the ‘mil’. Painted floors or walls in basements will likely have a longer curing time. Always ensure you allow enough curing time prior to use.
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