Pressure washing Halifax homes: doing it right after a long wet winter

Halifax winters leave a lot behind. By the time the snow finally clears in late March, most homes round here are wearing six months of grime. Green algae on the north side of the siding. Black lichen creeping along fence rails. Salt residue on anything within a kilometre of the water. A layer of road slush on the front walk you cannot get off with a garden hose. Pressure washing in Halifax really runs from late April through June, and if you only do it once a year, this is your window. Done well, the house looks new again. Done badly, you can strip paint, drive water behind your siding, or chew up your concrete.

Our coastal climate is rougher on surfaces than people give it credit for. Salt air gets into anything within sight of the harbour or the Bedford Basin, speeds up corrosion on fasteners and exterior hardware, and leaves a fine film on the south and east sides of the house that you can taste if you run a finger along the trim. The north side, where the sun barely touches between November and March, grows lichen and algae freely after a long wet maritime spring. Older wooden peninsula homes and century Victorians take the worst of it, because the trim is more porous and the paint is often older than the homeowner.

Treat first, wash second

This is where most homeowners go wrong, and it is the part that decides whether your house stays clean for a season or for a month. Algae and lichen are not dirt. They are alive. Lichen in particular sinks roots into porous surfaces, into wood, painted clapboard, and the rougher grades of concrete. If you blast it off with high pressure, you remove what is visible, the roots stay behind, and within four to six weeks of damp weather it is back where it was.

The order I work is: treat, dwell, then rinse. A sodium hypochlorite mix at low strength, applied with a pump sprayer or a proper soft wash setup, kills the growth on contact. It needs to dwell, ideally fifteen to twenty minutes on a dry day, before water touches it. Then a low pressure rinse takes everything off in one pass. The siding comes back genuinely clean, the roots are dead, and you buy yourself a full season, sometimes two.

Match the pressure to the surface

Here is where I have an opinion. For about three quarters of what gets pressure washed around a house, you should not be using high pressure at all. You should be soft washing. Pressure does almost nothing useful on biological growth that has not been treated first, and on softer surfaces it does plenty of harm.

What I aim for, by surface:

• Vinyl siding: around 1300 to 1600 PSI with a 25 degree fan tip, the wand at least 60 centimetres back, spraying downward across the laps, never up into them.
• Wood, including decks, fences, and oiled or stained cedar: 500 to 1200 PSI, fan tip, and the wood needs to be re-sealed afterwards because you will have raised the grain.
• Older painted surfaces: I do not pressure wash them at all if I can avoid it. Soft wash with chemistry, rinse off with a garden hose. Old paint, especially on the clapboard you see across the South End and North End, lets go in sheets if you push it.
• Concrete driveways and walkways: the only surface I use real pressure on, 3000 PSI and up with a fan tip, and even then never the red zero degree tip unless you want to gouge the surface.

The mistake I see most often is someone renting one pressure washer with an aggressive tip and pointing it at everything. The driveway comes out clean and the side of the house gets ruined in the same afternoon.

A retired lady in Fairview rang me this May about her back deck. Her nephew had been over the weekend before with a rented pressure washer and the red zero degree tip to clean the moss and weathered patches off the boards. He held the wand maybe four inches off the surface and went at them the way you would scrub a pot. A week later, half the moss was still there, because he never treated it first, and the boards had visible furrows where the tip had chewed into the soft grain of the wood. I came out, treated the growth, let the chemistry do the work, then went over the deck on a fan tip at low pressure and re-sealed it. It looks good now. The furrows in the boards are permanent. That part does not come back.

The thing most articles miss

Spray angle on siding. You want the wand pointed downward, into the lap, not upward. Vinyl and wood lap siding are designed to shed water that falls from above. Spray upward and you drive water under the lap and into the wall cavity. I have opened up walls in Hammonds Plains where the sheathing was soft and mouldy behind perfectly fine looking siding, because someone had washed the house from the bottom up. Always work top down. Always spray with the laps, not against them.

A few last things. Pick a day with no wind and no rain in the forecast for at least six hours. Cover the plants, they do not enjoy sodium hypochlorite. And if your house still has the original single pane windows in it, common in the older peninsula stock, keep the wand well off them. The old glazing putty around those panes turns to chalk under any real pressure.

If pressure washing in Halifax is not how you want to spend a Saturday in June, that is what I am here for. I take care of pressure washing for homeowners and landlords across HRM on a fixed price quote, never by the hour, so you know what the job costs before I start. You can reach me at tom@highland-property.com or get a quote through the booking page on the site.