Pressure washing a brick isn’t rocket science, but it has its tricks. If not done correctly, this procedure can cause imperceptible damage to the surface that can bring certain problems in the medium and long term.
Here is a short, but simple and precise guide from Swift Painting on how to pressure wash brick the right way to make your brick walls look like new, while giving them a more durable protection over time.
What do you need for pressure washing brick?
Plastic wrap and some tape
Rotary scrub brush
Brick and mortar sealant
Safety shoes and goggles
Choosing the correct pressure washer is key to obtaining the best possible result. The most important factor to consider is the PSI (Pounds per Square Inch). A PSI of 2000 or less is most appropriate when it comes to pressure washing brick walls, as higher power can end up causing “scratches” or cracks through which water seeps into the wall, which is especially true in very old bricks that already have some wear due to the action of time.
Preparing the surface for pressure washing
Before you start pressure washing, it’s essential that you do a careful preparation of the wall and the area around it to prevent certain problems. To get started, take at least a week in advance to apply a mortar mix to the cracked portions of the wall, as well as to the joints between the bricks. Use the broom to remove dust and dirt, then apply the mortar.
The purpose of this is to prevent water from penetrating into the bricks, something that can cause mold to appear over time, as well as weakening the structure.
Finally, protect the surrounding area by moving any fragile items. For those elements that cannot be moved, proceed to cover them with plastic wrap or a similar material, including electrical terminals, air conditioning connections, windows, etc.
How to pressure wash brick in 5 easy steps
After 7 days of applying the mortar, it’s time to proceed with the funniest part of this matter, pressure washing.
1.- Apply water
Before applying the detergent, try to saturate the pores of the brick with water to prevent the soap from penetrating excessively, as it’ll be more difficult to remove later. Use a low-pressure nozzle and make gentle movements from the bottom to the top to ensure a uniform distribution of water.
2.- Apply detergent
Load the pressure washer with detergent and gently spray it onto the bricks using the same bottom-up motion – the idea is to use lots of soap and water, but light pressure. Allow the soap to work for a maximum of 10 minutes to remove as much dirt as possible. Remember to use an appropriate detergent for brick cleaning.
3.- Use a brush over difficult areas
This is an optional step that will depend on the degree of dirt accumulated on your wall. This is where you’ll most notice that using a quality detergent is important to easily clean those areas where grease and vegetable matter tend to accumulate.
4.- Pressure wash your wall
Adjust your pressure washer to about 800 to 1500 PSI, depending on surface conditions. Remember that too high pressure can cause damage to the brick, so it’s best to start with low pressure and increase if necessary.
This time, you’ll need to use a top-to-bottom motion to remove the detergent. Try to apply slow but steady circular motions, without staying too long in one spot. Once you have finished, wait for the surface to be completely dry and check if it’s clean. If necessary, apply a second pressure wash to remove any stubborn residue.
5.- Apply sealant
A quality brick and mortar sealant acts as a kind of protective layer to prevent other substances from penetrating the interior of the wall and damaging it, without ever changing the appearance of the brick and keeping it healthy for longer.