How to Clean an Exposed Brick Wall

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If your exposed brick wall looks beat up you may want to clean it. There may be plaster, cement or mortar caked all over the bricks. Holes or other damage may also be a concern. A few scrapes with a wire brush should first be applied and then go out and get yourself a power washer.

Power Washer with Brass Attachment

This seems to be the most successful method to remove stubborn debris and get down to the original red brick. Power washing machines can be purchased or rented from most hardware stores. They work with water so be sure and check your available water source. Check how far away a sink, tub or outdoor spigot is. Measure your distance with extra room for slack. This will determine whether you will need a separate long hose attachment.

  • Brass brush heads: these are the secret ingredient. They are able to remove mortar and plaster very well. Cement can be tricky. Gently chipping away with a mallet and chisel can break it up. Try power washing first and then chip if needed.
  • PSI: The stronger the power washer PSI (pounds per square inch) the more effective it will be. However, if it is removing the brick, adjust it. In addition, a protective suit is recommended. Power washers are notorious for shaving off layers of skin with one, out of control spray.
  • Power Wash Prep: Because of all the water runoff, you will have to buy or construct a makeshift tub to catch the water. Some hardware stores sell long plastic bins you can place along the edge of the wall. The problem is that the tub does not fit flush against the wall which will send water all over the floor. Attach a plastic sheet to the edge of the brick wall using cheap caulk along the edge. The cheap stuff will peel off the brick easily. Then have the other end in the tub. You may have to construct several of these, side by side, depending on how wide your wall is. For the bottom of the wall where the tubs cannot catch, you will have to go slow using pans or a row of rags.
  • Patch: Get a small bag of brick mortar to patch up any holes. You may also want a few bricks on hand for repairs. If color matching the mortar is an issue, leave a groove and fill with tile grout that closely resembles the original mortar. If the bricks are hard to match try to sand paper some of the color away.
  • Seal the Deal: Spray liquid silicone on your brick wall to protect the brick, mortar and its color. This can be a highly toxic and combustible process. Make sure your room has proper ventilation and that you wear an industrial grade Oshacertified double filtered face mask. You will need to stay away from the area for a day or two until the smell subsides.

Methods That Do Not Work

  • Muriatic acid – This acid will discolor your brick
  • Drill attachment – Creates a lot of dust and dark black marks on your brick
  • Sandblaster – Too strong and will destroy your brick before you even have a chance to see it
  • Polyurethane seal – Too glossy

One Response to “How to Clean an Exposed Brick Wall”

  1. October 01, 2010 at 11:13 pm, Steve said:

    Thanks for the great post. I have this ugly brick wall that I have been dreading for a looong time. This post finally inspired me to take on the project. I’ll let you know how it goes.


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