Cleaning of Mildew, Rust, Efflorescence, Algae Growth and much more…
Mildew and algae are commonly found on dirty, exterior wall surfaces that receive little sunlight. These organisms can grow wherever food (dirt) and favorable temperatures and humidity are found. Some cleaners work on mildew only, while others can also be effective on algae, and others can effectively clean both organisms, while also being effective for general purpose cleaning. It is safe to assume that if there is mildew and algae, there is also dirt. In such cases, the more comprehensive cleaner is necessary to effectively clean the wall surface. If recoating is planned, such cleaning MUST be performed.
Never use high pressure to apply cleaning solutions, as the solution may be driven through the finish and into the base coat and become the source of future staining.
The long-term appearance of any exterior wall depends primarily on the attention given to periodic cleaning. The only condition that MAY warrant use of acidic cleaners is efflorescence, which is discussed below
Oakland Power Washings priority is to protect people, vehicles, property and all surfaces not intended for cleaning from splash, residue, fumes, rinse and wind drift.
We protect grass and plantings by covering or with spray from sprinklers. Adjacent surfaces may need additional protection as well. Always contact the cleaning product manufacturer for more information about protection precautions they recommend.
Equipment – General Information
Leaning a ladder against any wall coated with Dryvit/stucco finishes can cause damage. It is normally most economical and efficient to use pressurized water for the cleaning/rinsing operation. The simplest method of delivering pressurized water is to use a High volume reduced pressure pumps. This is enough on most commercial and residential applications to both prewet the wall surface, and rinse away applied cleaning solutions.
Cleaning Solution Application
Application of cleaning solutions can be accomplished using a low-pressure sprayer, 200 to 350 kPa (30 to 50 psi), or through a pressurized water cleaning unit. The pressure used must be adequate to coat the finish surface with the cleaning solution and not more. Chemicals in the cleaner provide the cleaning action, not the force of the water spray used to apply the cleaner. Light scrubbing with a soft bristle brush may be necessary..
Pressurized Water Rinsing
In Closing we will rinse the wall with large amounts of clean, pressurized water from top to bottom before the cleaning solution can dry. All wall areas below the cleaned area must also be rinsed down thoroughly in a vertical section. Failure to completely flush the cleaned area and all wall areas below the cleaning solution may leave residues that may emerge upon exposure to precipitation. Pressure should normally be kept below 600 psi to remove surface contaminants that have been lifted by the chemical action of the cleaning solution, and to remove any residue of the cleaning solution itself. .
Other Common Stains
Oakland Power Washing offers many cleaning solutions that are specifically formulated for removal of other common sources of staining. This includes mud, various metals, egg, efflorescence, oil, grease, and smoke/soot.
Removal of Efflorescence
Efflorescence can occur on many surfaces. It is caused by the migration of water through the cementitious material and interaction with salts present in it. The water containing the salts works its way to the surface of the finish where the water evaporates and leaves the salts – efflorescence – behind, and is more easily noticed on darker surfaces. Efflorescence on the finish surface is more an aesthetic than a performance issue for the finish, however, the source of the water migration should be determined since it can mean a more serious problem exists elsewhere. It can be unsightly, and it is preferable to use general cleaning compounds and pressurized water to remove light efflorescence deposits.
Removal of Rust
Rust can occur on many surfaces. It is caused by the migration of water and metals. The water containing the rust works its way to the surface of the finish where the water evaporates and leaves the stains behind and is more easily noticed on many surfaces. Rust stains on the finish surface is more an aesthetic than a performance issue.
All buildings need to be cleaned and the exterior inspected periodically for damage and deterioration. This is an expected part of the life cycle cost of any structure.