House Washing Chemicals

A house wash is a chemistry job first and a rinsing job second. Get the mix right and the algae dies on contact with almost no pressure on the siding. Sun Brite Supply keeps fresh 12.5% sodium hypochlorite, surfactants, cover scents, and plant-safe neutralizers on the shelf in Gaithersburg. Questions about your mix? Call 301-519-9274 and talk to someone who washes houses in this climate.

Building a House Wash Mix That Works

Every effective house wash has three parts. Sodium hypochlorite kills the algae, mildew, and mold growing on the siding. A surfactant makes the mix cling to vertical surfaces and rinse clean. Water carries it all. The green film on north-facing vinyl is a living organism, and the goal is to kill it, not blast it off. That is why soft washing works at garden-hose pressure while a 3,000 PSI fan tip just smears the growth around and voids siding warranties.

Strength on the wall is what matters. Most siding cleans up with roughly 1 percent SH hitting the surface. Downstream injectors get there automatically because they dilute around 10 to 1, so straight 12.5% SH in the bucket lands near 1 percent at the wall. Batch mixers and X-Jet users have to do the math themselves. Heavier growth gets a second pass, not a triple-strength mix. Overmixing wastes chemical, stresses plants, and cleans no faster.

Dwell Time Tells You If Your Mix Is Right

Apply from the bottom up, let it sit 5 to 10 minutes, and never let it dry on the surface. If the growth browns out and lifts in that window, your mix is dialed. Gone in seconds means you are running hotter than you need to be and paying for it. Still green after ten minutes means the mix is weak or the bleach is old. SH loses strength every week it sits in heat and sun, which is a real argument for buying it fresh and local instead of letting big-box jugs age on a truck.

Protecting Plants, Pumps, and Paint

Wet the landscaping down before you spray and rinse it again after. For valuable plantings, dose the beds with Bleach Arrest to neutralize overspray instead of hoping rain gets there first. Hard well water fights your surfactant and spots windows, which is what So Soft water conditioner is for. And if the customer wrinkles their nose at bleach smell, a cover scent turns the after-odor into lemon or cherry for about 20 bucks a gallon.

Match the Problem to the Product

From the Field

Two patterns show up at our counter every spring. First, washers blaming their injector when the real problem is tired bleach. If your SH sat in a hot garage since October, it might be half strength by April, and no mix ratio fixes that. We turn our SH inventory constantly, so what you pick up here is fresh. Second, the artillery fungus call. Those little black dots on siding near mulch beds are spore casings, they are glued on, and a standard house wash will not touch them. That is a specialty chemical and a patience job, and honestly, sometimes the answer is managing the mulch, not scrubbing the wall. Call before you promise a customer full removal.

Related Collections

• Soft wash equipment
• Roof cleaning chemicals
• Concrete cleaning chemicals
• Deck and wood cleaners
• Degreasers
• Chemical additives
• Chemical injectors
• X-Jets
• Mineral stain removers
• Pick up chemicals same day at our Gaithersburg store

Frequently Asked Questions

What ratio should I mix for a standard house wash?

Aim for about 1 percent SH on the wall. Downstreaming straight 12.5% through a typical 10 to 1 injector gets you there. Batch mixing, use roughly 1 gallon of 12.5% SH per 10 gallons of finished mix plus surfactant.

Can I just use store-bought bleach?

Household bleach runs 5 to 6 percent and is often weeks old before you buy it. You would need twice the volume for the same kill, and the added sodium hydroxide in some retail bleach can leave residue. Fresh 12.5% costs less per percent of strength.

Will house washing chemicals hurt my landscaping?

Not if you manage them. Pre-wet the beds, rinse after, and keep runoff moving. For sensitive plantings, apply a neutralizer like Bleach Arrest around the drip line before you start spraying.

How long should the mix dwell on siding?

Five to ten minutes, and never let it dry. Reapply a light mist if a hot wall starts flashing off. The growth should visibly brown out before you rinse.

What is the surfactant actually doing?

Three things. It breaks surface tension so the mix penetrates growth instead of beading up, it slows the run-off so you get full dwell time on vertical siding, and it helps the wall rinse streak-free.

How long does 12.5% SH stay good?

Strength drops with heat, sunlight, and time. Stored cool and dark it holds for months, but a jug in a hot truck can fade noticeably in two or three weeks. Buy close to when you spray.

Do you sell house wash chemicals to homeowners?

Yes. Walk-ins are welcome at 16620 Oakmont Ave in Gaithersburg, and we will explain the mix and the safety steps just like we do for the pros. Call 301-519-9274 first and we will have it ready.