Power Washing and Roof Cleaning Forum

A Safe Approach to Modern Hard Surface Cleaning and Restoration

Pressure or power washing has traditionally been used as the standard to clean and maintain exterior hard surfaces or hardscaping. This cleaning process has rendered acceptable results for years because the standard surface to be cleaned was a basic flat concrete finish without color. Concrete design and application has changed drastically. Modern decorative concrete is rich in design, color, and finish. It can also represent a significant investment for the owner. This calls for revisiting how to properly clean and maintain many modern hard surfaces without causing damage.

Damage Caused by Pressure Washing

The desired finish for most modern concrete is achieved by working the surface to bring up the "cream" consisting of cement and fine aggregate as well as color. The result is a hard, smooth and rich finish. The use of pressure washing machines to clean concrete results in a tremendous amount of pressure used at very close range. This can result in a marked improvement in the overall appearance of the surface. Unfortunately, this can also tear into the delicate finish of the concrete, especially after using higher pressure or doing multiple cleanings.

The typical result is that the fine aggregate (generally sand) beneath the surface is exposed and the desired finish, including color, is partially or almost completely removed. This damage cannot be undone without a costly overlay because the exposed aggregate does not functionally retain efforts to re-stain or dye. It is compounded by the fact that the surface is now far more porous and prone to various stains. The new color is a dull tone that reflects the color of the revealed aggregate.

The Problem with Pressure Washing

Power washing has been and will continue to be a valuable tool for professional contract cleaners. That said, an experienced power washing contractor knows there is a real art to achieving acceptable results using the proper tools. Unfortunately, countless results show that pressure washing is the culprit for a very large percentage of damage caused to many hard surfaces.

Typically when a pressure washing wand is used, keeping a consistent distance from the surface is simply ergonomically challenging. Use of a surface cleaner greatly improves this problem for field areas. However, surface cleaners are designed for close proximity to the surface, spray tips generally ranging from 1" to 2" from the surface. This is simply too close in many cases to safely clean without causing damage to costly, fine hard surfaces.

The facts show that professional surface cleaners can and do "cut" into the finished concrete surface, and the circular rings of damage are unmistakable. While power washing will always have a place in exterior cleaning, many modern materials and surfaces dictate that it should be used as an effective rinsing tool from 1 or more feet away from the surface, not inches.

Other hard surfaces, such as stone, can be severely damaged using pressure. Many hardscapes use softer stones, such as sand and flagstone, which obviously need to be handled delicately. Sedimentary stone such as slate, flagstone and limestone can have a relatively high resistance to direct, vertical pressure but are highly prone to delamination and can be severely damaged by the use of pressure washing.

How to Care for Modern Hardscapes Properly and Safely

Today, modern decorative concrete and hardscaping can be safely and efficiently restored using little or no pressure and the results attained are far superior. Advances in environmentally safe, incredibly effective chemicals, as well as professional application methods, allow experienced professionals to remove all sorts of stains including biological staining, rust, battery acid, fertilizer, efflorescence, grease, oil, and dirt. The stunning results provide a more comprehensive clean that lasts far longer and cause zero damage to modern hardscape surfaces.