How to Paint the Exterior of a Brick House
Should you paint brick?
Sometimes people are inclined to paint a house exterior to cover the bare brick siding. This is usually because it has become weathered or stained over time, and the expense of a brick restoration is out of the question. Painting brick is not usually advisable, because this substrate is very porous and absorbent of moisture, therefore making painting difficult. If you are set on it, there are some important things to consider.
Firstly, understand that painting brick is not reversible. You can repaint it again to change the color but you will never be able to return to the former exposed look. You should always consider if an improved appearance can be achieved instead by a cleaning or power-washing, or even a sandblasting. Some Toronto painting companies are capable of such work, and likewise should be offered in other cities as well. Moreover, you might be surprised at how the pricing compares to the alternate option of exterior painting. Some people's main concern is that there is old paint splatter on their brick house, and think hiring painters to cover it up is the only solution.
If you go ahead with painting, you need to determine if your brick has a sealer on it. Some sealers are almost invisible to the eye, and can be tested by spraying water on it. If water beads on the surface, then you have a sealer present. If this is the case, or you find that your brick is totally raw, surface preparation must be done to achieve a sound and clean surface. Cleaning or power-washing is essential to remove dirt and grime, as well as removing any loose mortar and debris that may have collected in the joints or near soffits, etc. It is absolutely essential to allow unsealed brick to dry afterwards for 3-4 days minimum. This allows the brick to dry out, as it can hold moisture for quite a while. If there is any loose dust or masonry it should be scraped with wire brushes, as you don't want any loose material getting between the paint and the substrate. large gaps in the joints should be re-pointed, or filled properly, because deep holes will not get painted properly and allow moisture to penetrate the wall, leading to problems later on.
Do it right now - less headaches later...
If your brick was sealed, you have to consider whether it is paintable directly or needs an additional primer. You can simply try an adhesion test, which means painting some of the finish paint on and allowing it to cure for a few hours, and trying to rub it off. If it cannot be removed with your fingernail, then you will be fine, and you just need a high quality vinyl-based paint. For unsealed surfaces, you should use a masonry primer. You will find that a primer is going to reduce the amount of paint needed since it seals and prevents unnecessary absorption. More importantly, the primer allows for great adhesion to the brick, which can be an issue over time.
Its also very important to make sure all areas are sealed well with primer and paint, because if water can get behind the paint and into the brick, such as through cracks, the moisture can cause peeling and de-lamination of the paint. The best deterrent to this is a high quality masonry primer, because it is designed to fight the natural chemistry of masonry products when exposed to moisture, such as the phenomenon of efflorescence. My Toronto painting company has recently consulted a customer regarding such a problem with brick, where paint simply peeled off without effort. The area in question was located near the ground, where moisture was plentiful. The fact is that even if you follow all needed steps to painting brick, an underlying moisture problem can cause premature failure. Paint can only do so much; but preparing and priming properly are your best tools towards a long lasting paint job.
The Essential Prep Checklist
Making your brick wall look as good as possible before painting guarantees a great paint job, and will allow it to last. Don't forget these essential steps:
- repointing the brick where mortar has fallen out, worn away, or is just too deep. This can be labor intensive depending on the age and condition of a brick wall, but well worth it.
- fill any holes from old house fixtures where bolts and screws were attached. Use the same mortar as for pointing.
- clean mildew and dry thoroughly before painting. This is usually an issue near the ground or at areas where rain runoff accumulates.
- If your brick is fairly porous, make sure to apply a good amount of primer, 2 coats if necessary, so that you build up the coating, and this will provide a smoother finish.
Finally, you want to pick a finish paint that is going to look great while protecting your house. A premium latex exterior paint in a flat finish is great looking, or upgrade to an eggshell or satin for a little extra shine and durability.
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