House Washing in Jacksonville, FL
House washing is not pressure washing. The green and grey film on Jacksonville siding is organic growth, and it comes off with a cleaning solution at low pressure. Force is what cracks stucco, strips chalking paint and drives water behind lap joints. We wash siding, soffit, fascia and trim at low pressure, and we tell you what pressure we are using before we start.
Why siding should not be pressure washed
Siding is a rain screen, not a sealed surface. Lap siding overlaps to shed water running down it. Point a high pressure wand upward under a lap and you push water the wrong way, behind the cladding, into the sheathing and the wall cavity. You cannot see that damage on the day. You see it later, as staining, soft trim or mould inside.
The other failure modes are immediate. High pressure strips chalking or failing paint, etches stucco, raises the grain on wood and forces water past window and door seals. On fibre cement it can damage the factory finish.
None of this is necessary, because the staining is biological. A cleaning solution kills the growth and lifts it; the water only rinses. The work is done by chemistry and dwell time, not by force. That approach is what the trade calls soft washing.
The full comparison is here, surface by surface, with the pressure ranges each material takes.
What the green and grey film is
On siding it is algae and mildew growing on the surface, feeding on the moisture and organic deposits that sit there. Jacksonville supplies both generously.
- Morning relative humidity averages 88 percent and never drops below 85 percent in any month. NOAA NCEI
- 53.40 inches of rain a year, with June through September each above 6.7 inches. NOAA NCEI, 1991 to 2020 normals
- 115 days a year with measurable rain, so walls spend much of the year damp. NOAA NCEI
That is why it always shows up in the same places first. North facing walls, anything under deep eaves or tree cover, and the lower courses where irrigation overspray lands. A wall in full afternoon sun on the south side of the same house can look fine while the north elevation is green.
It is worth knowing that this is different from the black streaking on your roof. That is a specific organism, Gloeocapsa magma, and it needs its own treatment. See roof cleaning.
Your siding material, and what it needs
Vinyl siding
The most forgiving material and still a low pressure job, because the risk is water behind the laps rather than damage to the vinyl itself. Older vinyl can also be chalky and faded, and cleaning will make that more obvious rather than less. We will tell you if we think that is what you are looking at.
Stucco
Porous, and common on Florida homes. It holds growth in the texture, so it needs dwell time rather than pressure. High pressure etches the finish and can drive water into hairline cracks. Any existing cracking gets pointed out before we start, because washing will not hide it and water should not be forced into it.
Fibre cement, such as Hardie board
Durable, but the factory finish is the thing you are protecting and it is not a repaintable surface in the same way. Low pressure only, and we keep the wand off the butt joints.
Painted wood
The most condition-dependent of the group. Sound paint washes well. Chalking, flaking or failing paint will come off, and no amount of care changes that, so if your paint is at the end of its life a wash may be the thing that reveals it. Worth knowing before rather than after.
Brick and masonry
Tolerates more than siding, but soft or failing mortar does not. Older mortar joints can be washed out by pressure that the brick itself shrugs off, so the mortar sets the limit, not the brick.
Before and after
The same wall, before and after a low pressure siding wash. Note the growth concentrated on the shaded elevation and the lower courses. We will publish Jacksonville project photography here as we build it up.
How a house wash runs
- We walk the elevations first. Material, paint condition, cracking, failed sealant, open vents, light fittings and anything that should not get wet.
- Planting and hard surfaces get wetted down. Beds below the wall are soaked before we start so anything reaching them is already diluted, and rinsed again after.
- Solution applied at low pressure, working bottom to top so it does not run over dry surface and streak, then given time to work.
- Rinsed top to bottom at low pressure, with the wand angled down rather than up under the laps.
- We walk it with you and are straight about anything that did not fully lift. Oxidised vinyl, chalked paint and long-standing staining on porous stucco do not always come all the way back.
If the roof and gutters also need doing, they go first, so run-off from above does not land on freshly cleaned siding. See gutter cleaning.
What moves the price on a house wash
- Size, and which size. Local operators band house washing by the home’s square footage, not by measured wall area. That matters and almost nobody explains it, so we have written it up on the cost page.
- One storey or two. Two storey work needs more reach, more setup and more care about what is below.
- Material and its condition. Porous stucco and chalking paint both take longer and carry more caveats than sound vinyl.
- How far the growth has gone. A light film and a fully colonised shaded elevation are different jobs.
- Access and what sits against the wall. Mature planting, screen enclosures, decking, narrow side returns and slopes all slow it down.
- Water supply. Whether there is a usable outside tap and what flow it gives.
- Whether soffit, fascia, trim and shutters are included. They should be quoted explicitly, not assumed either way.
House washing questions
Will it damage my siding or paint?
Low pressure with a cleaning solution is the method siding needs, and it is what we use. The honest caveat is paint at the end of its life: if your paint is already chalking or flaking, washing will take some of it off, because it was not holding on. We check paint condition before starting and tell you what we expect, rather than discovering it together halfway up a wall.
What is the difference between house washing and pressure washing?
House washing is soft washing: a cleaning solution at low pressure, with dwell time doing the work. Pressure washing uses force and belongs on concrete, pavers and other hard flatwork. The words get used interchangeably across this industry, which is part of why people end up with a pressure washer pointed at their siding. Full comparison here.
How long will it stay clean?
It depends on the elevation rather than on a number. A shaded north wall under tree cover will show growth again well before a sun exposed wall on the same house. Irrigation overspray hitting the lower courses shortens it further. We would rather look at how your walls are actually behaving after a season than sell you a fixed interval.
What about my plants?
Beds along the wall are wetted down before we start, which dilutes anything that reaches them, and rinsed again afterwards. We keep solution off foliage where we can. If you have anything you are particularly attached to, point it out when we quote and we will plan around it or cover it.
Do you wash soffit, fascia and shutters too?
They can be, and they should be specified in the quote rather than assumed. Soffit in particular collects a lot in this climate and is usually worth including. Shutters sometimes come off better than they clean in place, and we will say which yours are.
Should I wash before painting?
Yes, and any painter will tell you the same: paint does not bond to a surface with live growth on it. If painting is the plan, say so when you book, because a wash for paint preparation is a slightly different job from a wash for appearance and it is worth getting the sequence and the timing right between the two trades.
Get a house wash quote
Tell us the siding material if you know it, one storey or two, and which elevations are worst. Or call (904) 555-0127.