Picture a quiet Saturday morning. You’re in the driveway with your coffee, and the north side of the house has a gray-green film that a garden hose won’t budge. A University of Georgia story notes that in Georgia’s humid climate, mold and mildew can turn wood siding a “dirty-looking, splotchy gray.” You start to wonder whether you could clean it yourself.

What exactly is soft washing?

Soft washing uses chemistry instead of force. You coat the wall with a cleaner at low pressure, give it time to work, then rinse it off gently. The house washes we checked list sodium hypochlorite as the active ingredient. Purdue Extension calls a 5 percent solution of it ordinary household bleach. Some products for homeowners come ready to use. One label has you attach a garden hose to its built-in nozzle and spray straight from the bottle.

The honest decision: is DIY right for your house?

Start with two papers: the product label and its safety data sheet (SDS). The label is the legal set of directions, and the SDS explains the hazards.

Document What it says
Mold Armor E-Z House Wash label (5.25% sodium hypochlorite) DANGER, corrosive: causes irreversible eye damage and skin burns. Wear goggles or safety glasses and rubber gloves. Do not use or mix with other chemicals.
Mold Armor E-Z House Wash SDS Do not mix with acids, ammonia or other household chemicals, as dangerous fumes may result
HornerXpress 10.5% sodium hypochlorite label (EPA-accepted, 2011) Avoid breathing spray mist. Wear goggles or face shield, protective clothing and rubber gloves. Mix only with water according to label directions.

Even the ready-to-use house wash says DANGER. That’s no reason to panic, but it is a reason to take the gear seriously.

Now look at your house. A single-story home with siding you can reach from the ground is a fair DIY candidate. A two-story home with high gables means ladder work, and that changes the whole project. OSHA’s portable ladder card starts with a simple rule: read and follow all labels and markings on the ladder. It also calls for three points of contact while climbing, a check for overhead power lines, and staying off the top three rungs of an extension ladder. If that makes your palms sweat, listen to them. Water supply is part of that choice, so see how much water a house wash uses.

A label-first DIY setup checklist

Your own product’s label overrides anything here. These steps come from the labels and SDS above.

  1. Read everything first. Note the dwell time, the gear and what the product must not touch.
  2. Suit up as directed. That means goggles or safety glasses and rubber gloves for the house wash above. Its label also warns that it may stain clothes and shoes. Its SDS says respiratory protection should not be needed when used as directed with adequate ventilation. The stronger label says to avoid breathing spray mist.
  3. Test a hidden spot. The house wash label says to test an inconspicuous area first. It also says not to use it on cedar or redwood less than 2 years old.
  4. Protect the yard. Spray surrounding plants with water before and after, and avoid contact with vegetation, as the label directs. Keep runoff out of storm drains. The label calls the product toxic to fish and aquatic organisms.
  5. Pick a still day. The label says not to use it in windy conditions.
  6. Never mix your own blend. Don’t add other cleaners or chemicals. If a product must be diluted, use only the label’s own directions, with water only.
  7. Apply and wait as directed. The ready-to-use label says to work from the ground upward, wait 10 minutes, then rinse well with water. Yours may differ.
  8. Mind the metal. The label warns that prolonged contact of undiluted product with metal may cause pitting or discoloration. One homeowner on a roofing forum soft washed with a 5% mix and said the stainless wand on their sprayer developed pinhole leaks.
  9. Store it right. Keep the lid closed, in a cool, dry place away from sunlight and heat, where children can’t reach it.

When to call a pro instead

Hire a professional if:

  • You’d need a ladder above the first floor. Every rung adds risk, and you’d be spraying a corrosive liquid overhead while you climb.
  • The growth is on the roof. A roof is no place to walk around with a sprayer. Start with whether roof cleaning is worth it.
  • Your siding is delicate or unusual. Think young cedar or redwood, stained wood or anything the label leaves out. Stained wood has its own prep steps, as in deck prep before you stain.
  • Your health or comfort says no. If eye or skin hazards worry you, or you can’t wear the gear the label calls for, skip the chemicals.
  • The growth keeps coming back. Purdue Extension says mildew is most common on walls behind trees or shrubs, where air moves poorly. A pro can point out spots like that while they work.
  • You just don’t have the time. Prep, application, rinsing and cleanup all take time, and the label’s wait period is only part of it.

Before you book, use our questions to ask a house washing company, including which cleaner they use and how they’ll protect your plants. Check what pros publish in our house washing cost guide. If you’d rather use a pressure washer yourself, read pressure washing mistakes homeowners make first. Our methodology explains how we check sources. For roofs, what to expect from a roof soft wash is worth reading first.

Sources

Checked 2026-10-08. Labels and safety data sheets are quoted for what they say about their own products. No maker endorses or is endorsed by this site. Follow the label on the product you actually buy.