What kind of siding is it?
There are different types of house siding such as vinyl, brick, hardy board, shaker, etc. The industry standard for house wash is sodium hypochlorite but Cleansol BC is an alternative depending on the material. When the house siding is made out of wood, the paint has organic ingredients, or if the metal is galvalume, use Cleansol BC. For the most part , use SH (sodium hypochlorite) but when in doubt, do a test patch.
Prep for House Wash
Cover all exposed electrical that is loose and wooden doors and patio fans. Make sure all patio furniture is out of the way, pet toys, cars, etc.
Surfactant
Use surfactant (soap compatible with SH) to help the SH adhere to the siding longer for longer dwell time. Plus, it smells nice as if the house just took a shower. Good surfactants we use is from Southeast Softwash.
Temperature for House Wash
The outside air temperature affects how to do the work. On a hot day in direct sunlight, one must work faster because you should rinse application of chemical before it dries out. Take more precaution with anything metal. During colder days, mix Agent Green with the surfactant so that the SH is still as potent as in warmer weather. We have killed much mold and fungus even in cold weather. The right products help with all situations.
Technique and Tools
Do not pressure wash a house at close range or even medium range if the tip is too strong. You will damage the siding and create striping. Use low pressure and try to avoid shooting directly under the shingles and go with the shingles. Shingles overlap not only vertically, but horizontally, so go with the overlap, not against and keep a nice steady back and forth movement.
For house wash, some situations are ok to shoot upwards and some are not ideal. Some older homes have more delicate shingles and no insulation. In that case, we used ladders and rinsed downwards with a ball valve. That house was low enough for ladder work.
Some houses are too high and need either a stronger pump for water reach or additional tools like Vic’s Tip which it just a connection to attach and tip to a lightweight DI pole. Our pole has a 35 foot reach. The nice thing about Vic’s Tip is that you can connect any tip and it shoots the water horizontal or down if the house sits lower and it can shoot up even higher. A professional has to assess what to use on the building. One size does not fit all. For the most part, a soft wash wand and a shooter tip can reach a lot of houses but some houses are beyond the reach of the spray. The pump gpm and tip determine how high the water will reach.
Ladder Safety
Sometimes ladders are necessary for a house wash. Make sure you have stabilizers and ladder levelers. They both ensure the ladder will not tip over. The stabilizers also stop the ladders from leaning directly on the gutters. We prefer Level-Eze for levelers. You can plop the ladder to lock down into place instead of adjusting by hand or foot like some of the others. Make sure the angle of the ladder is correctly against the house.
Plants
One person should irrigate the plants before, during, and after to dilute the chem. Salt and water make up most of SH, so water dilutes it. One can never irrigate the plants too much during the house wash.
Two People
One person can soft wash a house but it is a lot more difficult. One huge reason is there should always be a safety person in case there is an accident. It is easier to both irrigate the plants and also do the wash at the same time. The water person can create water shields to other things by spraying a mist over the object. One person could also help pull hose when the hose gets stuck behind an object. The person doing the spray does not have to do a constant back and forth. Sometimes, some one has to foot the ladder as well while the other person climbs if the bottom is on a bad surface.
Rinse
Make sure the chem does not dry out all the way and rinse thoroughly. Overcast, mid temp days are the easiest days for soft washing a house. Remember to purge the chem line and do a final watering of all the plants. Don’t forgot to remove every thing you taped off or covered after done rinsing.