Many architects opt to use brick for the facades of the houses they build because of its very durable nature and the classic look it gives home exteriors. However, over time, brick can accumulate all kinds of dirt, grime, and debris such as stains from water, rain, and snow, algae, mold and mildew, wasp nests, bird droppings, and salt spots. All of these detritus can be removed effectively with pressure cleaning. Brick facades may also need cleaning immediately after construction to remove the excess mortar and complete the finishing or maybe, once a year to keep them maintained and looking great.
Understanding Types of Bricks and Mortar
Before you begin, you need to check with the builder about the kinds of mortar and brick used and work out your pressure cleaning tools and strategies accordingly. Check if the brick is sand faced. The sandy layer is typically of a different color than the brick under it. When power washing you need to make sure that you don’t accidentally remove the sandy finish so that you’re left with patchy brick exteriors with red and orange sections. Some bricks are of the sponge variety and soak up all the water you spray on them. Considering that you need to spray detergent and give it time to work, pressure cleaning can become tricky if the brick soaks up the soapy water as well.
Also, check with the builder about the kind of mortar used. Most builders use Type N for binding bricks that has a compressive strength of 850 PSI. For working with block, they might opt to use Type S that has a compressive strength of 1800 PSI. This mortar is more resilient and may not come off easily with pressure cleaning.
Equipment Needed
You’ll need some basic equipment to help with the power washing job.
- Pick out a low-pressure power washer with 500 to 1,000 PSI when working on brick walls or you could erode and damage them.
- Soft bristle brushes, an acid brush, and dry wire brush
- Pump sprayer to apply the cleaning solutions for mold and other residue
- Nozzles for pressure cleaning including a black tip for applying detergent
- Appropriate solutions for dealing with mold and mildew, and mortar stains
- Safety goggles to protect your eyes, and gloves to protect your hands and for a better grip
Cleaning Mold and Mildew
If you’re dealing with mold, mildew, and algae, you’ll need to clean it off before you begin the pressure cleaning. Check with your supplier for the right kind of chlorine or any other chemical that removes such vegetation effectively. Here’s how to proceed.
- Use a chlorine and water solution to clean brick exteriors. Using equal proportions, make a solution in a bucket and fill it into the pump type garden sprayer.
- Hose down the bricks to wet them, thoroughly. If you’re working on a large area, you might want to work on small sections at a time.
- If there are plants around the wall, make sure you wet them and cover with protective tarp to protect them from damage. Also, wet any loose soil so that the chemicals you use are diluted.
- Begin spraying the bleach solution on the top of the wall and work your way to the bottom.
- Give it time to work for a few minutes, but make sure the solution does not dry.
- Rinse a small area to check if the bleach has been effective.
- If the stains are too serious, you’ll have to use pure bleach and an acid brush on a broom handle to scrub the stains off.
- Rinse with clean water.
Cleaning Mortar Stains
To clean mortar stains, you can use muriatic acid or acid based masonry detergent. Check with your supplier for the appropriate chemical depending on the kind of masonry you’re dealing with. If you see rust that accumulates from irrigation well water, ask about the chemicals you can use. Depending on the client’s requirements, look for eco-friendly products that won’t damage the surrounding areas. Here’s how to proceed:
- If you’re using muriatic acid or any other chemical, use them according to the directions provided by the manufacturer. Typically, muriatic acid should be mixed with water in the proportion of one part acid and three parts water. Take care to wear gloves and mix it gently to avoid splashing.
- Hose down the brick wall thoroughly.
- Apply the solution and scrub with an acid brush. Allow it to stand for about 10 to 15 minutes, but make sure the wall does not dry out.
- Rinse it through using plenty of water.
- If you cannot use acid on the mortar, pre-soak the area with whatever solutions the manufacturer recommends and scrape off with a metal ice scraper.
Prepping the Brick Wall Surface
Check the mortar between the bricks. If there is any mortar missing or damaged, you’ll have to repair it or you risk the water seeping into the interior of the wall. Allow the mortar a week’s time to set before beginning with the pressure cleaning.
Pressure Washing Process
Using a step-by-step approach, you can clean the brick exteriors efficiently and thoroughly.
- Hose down the bricks with a regular garden hose. Once they have soaked up enough water, they can allow the detergent to work without absorbing it.
- Apply the detergent by spraying in even strokes horizontally. Begin at the bottom of the wall and then move gradually to the top.
- Allow the detergent to sit for about 10 to 15 minutes.
- If you see tough stains, you could use a rotary scrub brush to clean them off while the detergent does its job.
- Use a gentle spray nozzle to wash down the wall, starting at the top and moving steadily to the bottom.
- Take care never to spray directly on the mortar joints or the corners of the building or you risk blasting them out.
- After giving the bricks time to dry, you might notice a powdery, white residue forming on them. This residue is called efflorescence and forms as a result of the salts being drawn from the bricks. Using a brush with soft bristles, remove the buildup gently.
- Following the brick manufacturer’s recommendations, you can apply a siloxane or silicone sealant to prevent future dirt or stains from accumulating on the walls and maintaining the effects of the pressure cleaning for a good long while.
Using these tips and pressure cleaning, you can clean the exteriors of brick houses and have them looking as good as new by bringing back the natural, traditional feel of the house.
References:
1.“Pressure Wash Your Home Exterior.”Lowe’s. n.d. Web. 2 Sept. 2016
2.“Construction Brick Cleaning and Pressure Washing.” Ultimate Washer. n.d. Web. 2 Sept. 2016.
3.“How to Power Wash a Brick House.”American Washing. 16 Feb. 2015. Web. 2 Sept. 2016.
4.“How to Clean Bricks.“WikiHow. n.d. Web. 2 Sept. 2016.