In our previous blog post about power wash troubleshooting process, we have explained how to troubleshoot problems like algae, mold, mildew, rust stains, bird excrement and artillery fungus. In this post, we would explain some more problems which should be solved for better results.
Acid Rain Stains – Acid rain stains are left behind by mineral laden, polluted rain. When this rain dries on the surface the mineral residue is left behind causing dark-colored drip marks. A good surfactant with a cloth, pad, or soft bristle brush is very effective for cleaning these stains. Do not guarantee any final result to the customer as the outcome will vary depending on how long the stain has been there and the quality of the surface the stains are on. These stains are very prominent on gutters.
There are “touchless” cleaners designed for surfaces like factory-painted gutters. These are usually made with butyl or an alkaline “action chemical” like sodium or potassium hydroxide. These cleaners can be a little tricky to use, but they will usually take off most of these stains without any hand-scrubbing.
Oxidation – Oxidation (chalking) is defined as any chemical reaction that is a combination of a metal with a gas. Oxidation is the transfer of electrons from the metal to the gas. This leaves a chalky residue on the siding that will dull the exterior of the surface. Keeping the surfaces clean will help keep the oxidation from forming. Extreme caution should be used when cleaning oxidized surfaces.
Many times these surfaces will need to be cleaned, primed, and painted to look good again. It is very important to inform the customer prior to cleaning about the potential outcome and to discuss the next course of action.
Cleaning heavily oxidized siding will leave streaks and striping that is very unsightly.
It is recommended to apply the primer and paint as soon after washing as possible to avoid coatings issues.
Efflorescence – Efflorescence is a white crystal like or powdery deposit on masonry materials like brick, concrete, etc. caused by water seeping through the substrate. Water carries mineral salts to the surface where it is deposited as the water evaporates. In many cases efflorescence will stop on its own. 
When it needs to be removed an acid-based cleaner is often used. Hydrochloric (muriatic) acid is the common ingredient. It can be extremely harmful to soft tissue and proper safety and caution should be exercised.
First wet the surface and apply a 1 part acid 12 parts water solution to the surface. Agitate as necessary and rinse thoroughly.
Egg Stains – Egg stains are caused by mischievous kids, usually on October 30th. The best way to get rid of these stains is to clean them as soon as they occur. These stains should be treated before washing the entire structure. A simple and quick way to clean egg off most surfaces is to use a solution made up of 50/50 vinegar and warm water. If this does not work then you will need a stronger detergent, and we would recommend trying a butyl-based cleaner or an enzyme-based cleaner. Be careful on some surfaces with some cleaners as you do not want to remove paint or discolor the surface in any way. The results you get with cleaning will depend on how long the stain has aged on the surface. Eggs often will lift the paint off a surface if left on too long.
Spider Webs – Spider webs usually require a pole and/or a rag to remove. Webs usually survive a 3500 PSI blast from a power washer.
Tape Residue – Tape residue is often found on surfaces where signs or decorations were in use. Pressure washing has little effect on these marks. A good citric-based cleaner and a soft cloth are very effective in removing the residue. If there is an extreme amount of tape residue, solvent-based cleaners can be effective for melting the gluey substance.
Caution: use extreme care when using any solvent-based cleaner on any substrate or surface. It can remove paint and/or leave the area appearing worse than when you started.
Tree Sap – Tree sap is a very stubborn stain that would take entirely too much pressure to remove without aid. The best recommendations to use for cleaning sap are raw linseed oil, mineral spirits, turpentine, or automotive bug and tar remover. A stiff scrub brush may help. Once the stains are removed, you should do a cleaning with a detergent and cloth.
Commercial Restorations 