Soft washing uses three primary components: sodium hypochlorite (SH), a surfactant, and water. The sodium hypochlorite is the active biocidal agent that kills algae, mold, mildew, and bacteria. The surfactant reduces surface tension, allowing the solution to cling to vertical surfaces and penetrate porous materials instead of running off immediately. Water dilutes the solution to the appropriate concentration for the target surface. The exact ratios vary by application and are calibrated by the professional performing the work.
Sodium hypochlorite: the active ingredient
Sodium hypochlorite is the same compound found in household bleach, but soft wash concentrations are different from what you buy at the grocery store. Professional soft wash SH is typically supplied at higher concentration, then diluted on-site to appropriate levels for the specific surface and contamination. SH kills biological organisms by oxidizing them at the cellular level. When Gloeocapsa magma, the cyanobacteria behind black roof streaks, or algae on siding contacts SH at appropriate concentration, the organism dies. This is what creates lasting results, the organism is killed, not just rinsed away.
Surfactants and why they matter
A surfactant is a compound that reduces the surface tension of water, allowing it to spread and penetrate more effectively. In soft washing, the surfactant serves several functions. On vertical surfaces like siding, it causes the cleaning solution to sheet out and cling rather than bead up and run off before it can work. On porous surfaces like roof shingles or textured concrete, it helps the SH solution penetrate into the surface pores where organisms are anchored. The result is more uniform coverage and more effective kill rates.
Surfactants used in soft washing are formulated to be rinseable and are not persistent in the environment after thorough rinsing. Professional crews typically rinse surrounding landscape plants with plain water before applying soft wash chemistry and again after the rinse phase to dilute any runoff.
Are these chemicals safe for my landscape?
Properly diluted and properly rinsed soft wash chemistry poses minimal risk to established plants. The key is pre-rinsing landscape beds and plantings adjacent to the work area, avoiding direct overspray onto foliage, and rinsing again after the job is complete. Delicate plantings, potted plants, or recently seeded areas should be moved or shielded if possible. Professional soft wash crews manage runoff as a standard part of the job.
What about algae-specific or specialty products?
Some soft wash operations include specialty additives for specific problems. These may include:
- Rust treatment compounds: Oxalic acid or similar products for iron staining on concrete or masonry. These are applied separately from the standard SH mix.
- Degreaser additives: For heavy oil or grease contamination on concrete, a degreaser pre-treatment improves results before pressure washing.
- Mold-resistant additives: Some surfactant formulas include compounds designed to slow regrowth by leaving a residual film on the cleaned surface.
CARE uses sodium hypochlorite, surfactant, and water as the core soft wash mix. We do not disclose exact ratios, as these are calibrated by job type.
Why not just use bleach from the store?
Consumer bleach is typically 3 to 6 percent sodium hypochlorite. Professional soft wash SH is available at higher concentrations and is diluted to specific levels for each application. Beyond concentration, the application equipment matters. A garden sprayer cannot apply solution evenly at the volume and consistency that a dedicated soft wash pump system delivers. Inconsistent coverage leads to inconsistent kill rates and visible banding where the chemistry did not dwell long enough.
CARE's soft washing in Fort Worth
CARE uses professional-grade sodium hypochlorite, surfactant, and water for all soft wash services on Fort Worth homes and roofs. Call (945) 275-8031 or visit our house washing page to schedule service.