Vinyl siding cleaning and soft washing

This page is about the siding itself: what is growing on it and how to get it off vinyl and wood without damage. If you want the whole outside of the house done in one visit, trim, soffit and fascia included, that is our house washing service.

What the green and black stuff actually is

Three different things, and they all need the same treatment. Green is algae. It feeds on moisture and it loves the north and shaded sides of a house, which in Nova Scotia is most houses most of the year. Black streaks running down from the roofline are usually mildew mixed with runoff. Dark spotting on light vinyl that will not come off is often artillery fungus, which fires spores out of wet mulch and embeds them in the siding. That one is genuinely difficult and sometimes permanent.

None of it is loose dirt sitting on the surface. It is living growth with roots into the surface. That is the whole reason blasting at it does not solve it.

Why pressure washing siding is a bad idea

Pressure knocks the growth off. It does not kill it. Whatever is left in the surface grows back, usually within a season, and often faster because the surface is now rougher than it was.

Worse, vinyl panels overlap and are designed to shed water running downward. A high pressure jet aimed upward or sideways drives water up behind the panels and into the wall. You will not see it happen. You find out later when there is mould in the sheathing or a stain appearing on an interior wall. On older houses the risk is higher again, because pressure can get past window trim, force water into failed caulking and lift paint off wood.

The rule with siding: if pressure alone is removing it, pressure alone is damaging something.

What soft washing is

Soft washing uses low pressure, roughly what a garden hose puts out, combined with a cleaning solution that kills the algae and mildew at the root. The solution does the work. The rinse just carries it away.

Two things follow from that. It lasts longer, because the growth was killed rather than knocked back. And nothing gets forced behind the siding, because there is no real pressure involved. It is the method most siding manufacturers recommend, and using a pressure washer on vinyl can void the warranty on it.

The plants question

This is the first thing people ask, and they are right to. Soft wash solutions are hard on landscaping if nobody takes care. A crew that turns up, sprays a house and leaves will brown off the shrubs along the foundation and the grass underneath.

Done properly, everything gets wet down before, covered where it needs to be, and rinsed thoroughly after. The products we use are environmentally safe and will not harm plants, grass or animals. If you are getting quotes from anyone, ask them what they are spraying on your house and what happens to the garden. The answer tells you a lot.

How often it needs doing

In this climate most houses want doing every one to two years. Shaded and north facing walls, houses under trees and anything close to the water go at the shorter end. A south facing wall in full sun might go three. Keeping on top of it is cheaper than leaving it, because once growth has been there for years it takes longer to treat and on painted surfaces it can leave shadowing behind even after the growth itself is gone.

When it is worth having done

• Anything above one storey, where you would be up a ladder with a hose in your hand
• Vinyl siding, where the water intrusion risk is real
• Painted wood, where the wrong approach takes the paint with it
• Before you sell, because it is the cheapest thing you can do to the outside of a house
• Before painting, because paint over algae fails early

We bring our own water

No hose to run, no outside tap needed, nothing on your water bill. It also means we can work on a property where the water is shut off. We carry insurance and WCB coverage and we have been doing this since 1997.

Siding is one part of it. We also do full house washing across the HRM, deck cleaning, and paint prep and stripping for when the wash is step one of a bigger job. For commercial and industrial work we cover all of Nova Scotia, including building washing.

Send a couple of photos of the worst wall and we will tell you what it needs. If it is something soft washing will not fix, like artillery fungus, we will tell you that too rather than take your money and disappoint you.