How to use the Soft Wash Mix Calculator
The calculator uses the C1×V1=C2×V2 dilution formula throughout. Inputs are your target working concentration, the volume of mix you need, your surface type, and your surfactant family. Outputs are the exact mix recipe plus context: safe dwell range, substrate safety flag, and batch cost at your actual supplier prices.
1. Set your target SH% (slider)
Drag the slider to your working concentration at the nozzle — not the stock concentration. Typical targets: 0.5%–1% for vinyl siding and painted wood house washes, 1.5%–2.5% for stucco and concrete, 3%–6% for roof shingles with heavy organic growth. The slider runs 0.5%–6% in 0.1% steps. The calculator always assumes 12.5% SH stock — if your stock is different, the SH Mix Ratio Calculator handles custom stock concentrations.
2. Enter gallons of finished mix
Enter the total volume of diluted mix your job requires. Most house washes use 25–75 gallons depending on square footage; roofs can run 50–200 gallons. The calculator outputs SH stock gallons and water gallons from this total.
3. Select surface type
Surface type drives two outputs: the recommended dwell time range and the substrate safety flag. The calculator has pre-loaded limits for each substrate — if your SH% exceeds the safe ceiling for that material, the calculator compresses the dwell window and upgrades the safety flag to YELLOW or RED.
4. Choose your surfactant
Elemonator doses at 0.8 oz per gallon of finished mix; Cling-On and generic surfactants dose at 1 oz per gallon. Surfactant choice affects cost and cling behavior — Elemonator is the industry default for house washes; Cling-On is preferred on sloped surfaces where extended dwell is needed. The calculator includes surfactant in the total batch cost.
Surface reference — SH% ceilings and dwell windows
These are the input values behind the calculator. Dwell ranges assume standard SH% for the surface — higher concentration compresses the window proportionally.
| Surface |
Typical SH% Range |
Safe SH% Ceiling |
Dwell (std. concentration) |
Notes |
| Vinyl Siding |
0.5% – 2% |
3% |
1 – 5 min |
Tolerates higher concentration; shorter dwell on hot days |
| Stucco |
1% – 2% |
2% |
1.5 – 6 min |
Porous — rinse thoroughly to prevent efflorescence |
| Painted Wood |
0.5% – 1.5% |
1.5% |
0.75 – 3 min |
High SH% lifts paint. Pre-wet and keep concentration low. |
| Roof Shingles |
3% – 6% |
6% |
3 – 10 min |
ARMA max 6%. Longer dwell on lichen; rinse before direct sun. |
| Concrete |
1% – 3% |
3% |
2 – 8 min |
Densely packed — longer dwell effective on oil and organic staining |
| Brick |
1% – 2% |
2.5% |
1.5 – 6 min |
Avoid acid co-use. Efflorescence risk on aged mortar joints. |