Window Moss Removal in Parksville, Head to Sill

Watch one window through a wet Oceanside winter and you can trace the whole problem from top to bottom. Rain drips off the eave onto the trim over the opening, slides down the glass, collects along the bottom of the frame and is meant to leave through two or three small slots on the outside face. Moss appears at each point on that route where the water slows down and the sun never reaches. We work each window in the order the water travels.

Above the glass: the head of the window

Most wood-frame houses have a strip of flashing or a drip cap over each window, there to throw rain clear of the opening. Under a shallow eave that little ledge catches fir needles, maple seed keys and grit washed off the shingles, and moss roots into the pile. Once it does, the edge stops shedding water. Rain creeps back along the underside instead and into the joint between the head trim and the frame, a joint that sits above eye level where nobody checks it.

We pick the ledge clean along its full width and make sure the drip edge is open again. If moss on the roof above is washing down onto your window heads with every storm, the frames will not stay tidy for long, and roof moss removal is the job to sort first.

At the edge of the glass

Glass itself sheds water well, which is why moss rarely grows on it. The edges are another matter. A thin strip called the glazing bead or stop holds the sealed unit in the frame, and the hairline gap along its lower edge fills with a line of dirt that greens over by midwinter. That line sits right where a double-glazed unit’s edge seal is closest to the weather. We brush it out with a soft brush and keep the rinse at low pressure there, because driving water past that bead is how a clear unit begins to fog.

The bottom of the frame: track and weep slots

Everything running down the glass ends up here. On a sliding window the sash rides in a track that also serves as the drain channel, and the outer face of the frame has small slots, often behind a hinged flap, where the water is supposed to escape. In a shaded track the sequence is predictable. Dust and needles settle, moss takes hold in that layer, the slots close, and the channel starts storing water instead of passing it along. A frame that stops draining in the fall can then stay wet right through to spring.

We scoop the track out, open each slot from outside with a pick, then pour water into the channel and watch for it to come out. Seeing it run is the only real proof a slot is clear.

Below the sill: the drip groove and the siding

The water has two more places to cause trouble on its way down. A good sill has a groove cut along the underside of its nose so drops fall off rather than curl back toward the wall, and moss in that groove defeats it. Below that is the band of siding under each window, which takes the run-off from the frame and often shows a green or grey stripe. We clear the groove, wash the stripe off the siding with a low-pressure soft wash, and tell you if any trim feels spongy when pressed.

Patio doors are their own job

A sliding patio door is a window people walk through, and its track collects more than any other frame on the house: grit off shoes, pet hair, sand carried up from the beach, leaves blown across the deck. The track is long, low and sits beside deck boards that stay damp, so it fills faster than the windows above it. When a door starts to drag, the rollers usually get the blame. More often the track is packed. We empty the full length of it and the drain slots in the sill, and if the door still drags once the track is clean, that points to the rollers and we tell you so.

Dry summers hide it

Through a dry Oceanside summer, frame moss dries out, turns brown and shrinks, and a window can look as if it needs nothing at all. That dry plug in a weep slot swells straight back up with the first fall rain. Late summer, while the moss is brittle and the channels are empty, suits the work well, though spring is fine too. What matters is that the slots are open before the wet months arrive.

Where we see the most of it

On open waterfront lots facing the Strait of Georgia, frames on the water side tend to stay cleaner, since sun and wind dry them, while the landward wall is greener. On a treed acreage in Errington, the wall facing the woods keeps its windows damp long after every rain. Upstairs windows on two-storey houses are the usual reason people call us: clearing a track at the top of a ladder is awkward, and many homeowners in Qualicum Beach and Parksville would sooner not be up one at all.