To Rid Roof Pests, Remember Wet and Forget

The easiest way to eliminate unwanted green stuff.

Usually green is a good thing: It refers to things like cash, planet-friendliness, fresh beginnings, the great outdoors. But when the green of the great outdoors is algae, mildew or moss, it’s not a good thing if you find it growing on your house, sidewalk, deck, or driveway.

So some guys in New Zealand figured out a simple (and safe) way to eliminate the gross green stuff, and they eventually began to offer their product, Wet & Forget, in North America. When I heard their story and saw the spray demonstrated, I decided to give it a try.

Late last fall, we sprayed a section of our porch roof that never sees sunlight because it’s always shaded by a second-story dormer. As you can see in the “before” photo, the moss had created a lush carpet over the surface; it had been growing there for several years. (I guess we always had something more fun to do than crawl around on a roof with a bucket and a scrub brush. And besides, we were afraid we might scour the textured surface of the asphalt right off the shingles.)

The next part of the process could not have been easier! The instructions say to leave it alone and let the wind and rain (or snow) do the rest. And as the name indicates, we were supposed to forget about it. Well, that’s a cinch! In fact, by the time the last round of snow finally melted in late May, we had totally blanked out on our autumn attack against the moss and algae.

Wet & Forget’s results are gradual, but you’ll notice a definite improvement within just a few weeks after application (that is, if you remember to check). In our roof’s case, some of the moss even continued to vanish after the snowmelt. In the “after” photo below (taken nearly a year after we sprayed and forgot) you can see that a tiny bit of moss residue remains – but only along the highest edge, which is sheltered from wind and rain by the dormer. We will give that area another shot next spring (that is, if we remember). Overall, I am impressed that the porch roof is clean, not green.

Bonus Video: