Tile and Metal Roof Moss Removal Around Parksville

Tile and steel are built to last a long time, and on most of these roofs the covering will outlive several rounds of moss. What wears out sooner are the small parts: the rubber washers under screw heads, the overlaps between courses of tile or sheets of steel, the paint on a steel sheet, and the flashings that collect needles. Our job on these roofs is to get the moss off without hurting any of those. Around Parksville we see steel most often on rural buildings, especially the shops, barns and carports on acreages out toward Hilliers, where tall trees keep the panels shaded and damp for much of the winter. Tile turns up on houses scattered through the area.

We read the roof before we touch it

The first part of any visit happens from the ground and the top of a ladder. We want to know three things: what the roof is made of, what is growing on it, and where it is growing.

Material decides how we move. Steel can be walked once it is dry, keeping to the fastened strips over the framing. Concrete tile can take a boot in some places and not others. Clay tile takes very little weight at all.

What is growing decides how it comes off. Soft green cushions are moss, and they lift away by hand. Flat, crusty patches in grey, green or yellow are lichen, and lichen is treated, not scraped. On an open roof facing the water, some of what looks like moss from the driveway can turn out to be lichen once we are up close.

Where it is growing tells us where the risk is. Moss spread across the open face of a tile is mostly cosmetic. Moss packed into a lap, a valley or a row of screws is holding water exactly where the roof needs to drain.

Steel roofs: follow the fasteners

Rain runs off a steel panel too quickly for moss to settle on the flat. So on steel we look at the places where water stalls. On screw-down panels that means the rows of exposed screws, where needles catch against each head and moss grows into the gap. It also means the horizontal overlaps between sheets, the ridge cap, and the high side of every vent, chimney and skylight, where debris builds up against the obstruction.

We clear those lines with soft brushes and plastic tools, working downhill. A metal scraper would cut the coating, and bare steel under a scratch is where rust begins. While we are there we look at the screws. A washer that has gone hard and cracked, or a screw that has backed out, goes on the list we give you.

We only climb onto steel once it is dry. A damp panel with moss on it is slippery underfoot, and the dry spell between late spring and early fall is when most of this work gets booked.

Concrete and clay tile: where the weight goes

Concrete tile weathers. Once the factory surface wears off, the tile holds moisture in its face, and moss roots into it. The moss on the face is not the main concern. The concern is the moss in the pans and laps, which are the channels the roof drains through.

Every step on a tile roof goes where that tile is supported from below, near its lower edge where it bears on the course under it. The middle of a tile, spanning open air, is where cracks start. On clay, which is harder and more brittle than concrete, we keep footsteps to a minimum and do as much as possible from ladders.