Painting brick is more of a challenge than other surfaces in the home like plaster and plywood due to the fact that the surface of a brick is uneven and porous, therefore it hard to achieve a smooth finish.
Ensuring an even finish on brickwork involves both preparing the to-be painted surface properly, and ensuring that you use the correct paints and brushes for the job.
Here is a step-by-step guide from a general contractor on how to get a professional-looking finish to painted brickwork as a DIYer.
Ensuring that bricks are “paint ready”
It is not a good idea to paint brickwork that has significant damage to either the bricks themselves or to the mortar. Holes and cracks in brickwork allow water to be absorbed which then slowly leaches out and causes paint to flake off the surface of bricks. This is one of the two reasons (along with a lack of priming bricks) that we see so many botched paint jobs on brickwork.
Cracks that are more than an inch long, and holes more than a quarter of an inch in diameter need to be sealed with caulk before painting. Similarly, any visible damage to the mortar (holes and loose mortar for example) needs to be tuckpointed before painting.
New bricks and freshly tuckpointed mortar should wait at least a month (ideally over 3 months) before painting. The outer layer of fresh brick can be a bit powdery, and as this powder comes off it will take the paint off with it.
Thoroughly clean and dry bricks before applying paint
Brick’s rough surface means that they quickly collect dirt and dust. This debris creates a physical barrier between paint and brickwork, stopping paint from binding to the surface of bricks and causing the paint to peel off prematurely.
You, therefore, want to clean and dry the surface of bricks before you paint them.
Indoor bricks with efflorescence (a chalky white substance) can be cleaned with a sponge and warm soapy water. Do not use a metal wire brush to clean bricks as the wires can become dislodged in the brick and then rust.
Outdoor brickwork can be a bit trickier to clean, as exposure to rain can make them susceptible to moss and mildew. The best way to clean this is to spot clean any areas affected by moss or mildew with a solution of half a cup of trisodium phosphate with a gallon of warm water, and then to clean the whole wall with a pressure washer.
Leave bricks to dry for at least three days. The pores in bricks will absorb any water that is applied to them, and you need to let this water leach out of the bricks before you apply paint or primer. If you have used a pressure washer to clean your bricks then you should wait at least a week before applying your initial primer.
Apply a layer of primer
A layer of primer dulls the surface of brickwork, allowing you to achieve an even finish when painting.
It’s worth spending a little bit more money to get specialized masonry primer. This is usually a touch thinner than standard primer – a necessary feature to penetrate all the pores of the brick and is alkaline resistant because mortar typically has basic alkalinity. Since we recommend using latex paints for painting brickwork, you should use a water-based primer.
With external brick, we would recommend applying two layers of primer a couple of days apart each. This additional layer is necessary if the masonry has been affected by mold or mildew as extra scrubbing that you have done when cleaning this off the brick will lead to you having a rougher surface to paint.
Selecting the right paints and brushes for the job
If you do not have too much experience with decorating walls, we’d recommend using acrylic latex paint for brickwork. The acrylic resin in acrylic latex paint gives it an elasticity that helps it bind to and fill in hairline cracks and pores.
Masonry professionals and house painters prefer to use elastodynamic paint for painting brick (and most exterior walls, for that matter) due to its increased durability in outdoor conditions. However, the thickness of this paint makes it harder to work with than acrylic latex paint. In particular, elastodynamic paint has a tendency to “lump up” when painting, and these lumps of paint can crack when drying.
We would recommend painting brick with a brush or a roller, rather than with an air-sprayer. Paint needs to be properly worked into bricks, and air-sprayers, particularly those on the cheaper end of the market, simply do not apply paint with enough pressure to do this.
Brushes and rollers need to have long, durable bristles in order to reach into the pores and crevices of the brick. With brushes opt for ones with synthetic bristles of at least 2 inches in length. Rollers should have a nap of at least half an inch.
Brick generally requires two layers of paint, however, it should not need a sealer as you have primed the brickwork beforehand.
Maintaining your finish
Painted brickwork tends to deteriorate faster than other surfaces. You can expect to have to touch up a wall every 5-7 years, maybe even more regularly if you live in a humid climate.
It’s also worth remembering that to paint the brick a new color, you will need to first remove the existing paint and then repaint it again. This can be difficult to do without damaging the brickwork below, so make sure that you are fully committed to color before you start painting.
This article was contributed by Volodymyr Barabakh, the owner and Project Director of the homebuilding company Fortress Home.