Eight jobs, in the order the weather demands them, with what we saw on real roofs and gutters in Laurelhurst, Capitol Hill, Magnolia, Rainier Valley and Wallingford
Seattle's rain arrives in October and does not leave until spring, and November is the wettest month of the year at more than six inches. The exterior jobs that matter are the ones that get done before that: moss off the roof and the treatment on, the gutters cleared once the leaves drop, the downspouts flowing, and the windows and walls clean before the dark months make everything look worse than it is.
1. Get the moss off the roof and the treatment on
A roof that goes into a Seattle winter with moss on it comes out in April with more of it, because moss does its growing in the wet months. The fix is a hand cleaning now: debris blown off, moss brushed out of the seams, and a zinc-free moss-prevention treatment laid in bands so the first fall rain carries it through the shingles. In August, Sterling did exactly that on a Laurelhurst roof a few blocks from Union Bay; you can see the treatment line on our Laurelhurst roof cleaning page. In May, Bobby did it on a Magnolia roof that Sterling had photographed with moss in every course eleven days earlier, on our roof cleaning page. North-facing slopes under maples and firs go first, so check those from the street.
2. Clear the gutters after the first leaf drop, then again after the last
Big-leaf maples let go across late October and November, and one heavy wind can fill a gutter in a weekend. The gutters above were photographed on November 12 at a Wallingford home, packed solid along a flat roof, and Alexander K. cleared every run by hand that morning. If your house sits under maples, plan on two clearings, one when the first big drop is down and one after the trees are bare, so the gutters actually run through December and January. Our gutter cleaning page covers what a visit includes.
3. Check where the downspouts go
A clear gutter is only half the system. Walk the house after the first hard rain and look at each downspout: water should be leaving through a splash block onto ground that slopes away, or into a drain that is actually taking it. In the older, central part of the city some downspouts still run straight into the combined sewer, which is why Seattle and King County run the RainWise program, with rebates that cover most or all of the cost of a cistern or rain garden on eligible properties; the eligibility check is by address. Either way, a downspout that dumps at the foundation is the one to fix before the atmospheric rivers arrive between October and January.
4. Wash the windows before the dark months
Seattle's short days start in November, and a window that looked fine in July looks grey when the light is low and the sky is white. An exterior wash now, screens and tracks included, keeps the house bright through the months you spend inside it. Our window cleaning page explains what a full detail covers.
5. Soft wash the north wall
Green and black algae grow on the shaded side of the house for the same reason moss grows on the north slope of the roof: it never dries. A soft wash in early fall, low pressure and a cleaning solution rather than a pressure washer, takes it off siding without lifting paint, and it does the job before the wet season lets the algae spread. See house washing.
6. Pressure wash the walkways and steps before they turn slick
The first real rain turns a summer of dust and algae on concrete into a skating rink, and the front steps are where guests find out. A pressure wash of the walkways, steps and driveway now, plus a sanitizing treatment that slows the algae, keeps them safe until spring. Our pressure washing page covers surfaces and technique.
7. Clean the solar panels after the dry summer
Pollen, dust and late-summer smoke haze settle on panels through August, and in Seattle the rain that should rinse them does not arrive until the days are already short. A panel wash in September or October recovers output for the weeks of sun that are left. In March, Dany washed a Rainier Valley array that had gone dull under moss and grime; the customer's account is on our blog, roof moss removal in Rainier Valley. Details are on our solar panel cleaning page.
8. Book holiday lighting now
Our install season runs October through December and the calendar fills in the order the calls come in, so booking between September and November is what gets you the date you want. We take the lights down in January. Our holiday lighting page has the details.
Fall Questions From Seattle Homeowners
How late in the fall can moss treatment still go on a Seattle roof?
Any time the roof can be worked safely, but earlier is better. The treatment is a powder that rain dissolves and carries through the shingles, so a September or October application is spread by the first storms and is working before the moss grows. A December application still works, but the moss has had two wet months first.
Should the gutters be cleaned before or after the leaves finish falling in Seattle?
Both, if the house sits under maples or oaks. One clearing after the first big drop keeps the gutters running through the November storms, and a second after the trees are bare carries them through winter. A house with only evergreens nearby can usually manage on a single clearing in late fall.
Which fall exterior jobs can wait until spring, and which cannot?
Windows, walls and hardscape can wait if they must, because dirt does not damage them over one winter. The roof and gutters cannot: moss grows all winter and a blocked gutter sends water at the fascia and foundation every time it rains. If you do two things before November, do those two.
Our Recommendation
Do the roof and the gutters in September or October, before the November rain, and put both on a schedule so that next year they happen without you thinking about them. A Renew plan pairs a fall visit with a spring one; a Regen plan takes the whole list off your hands. Everything else on this page is worth doing, but those two protect the house.
Related: roof cleaning · gutter cleaning · moss removal and treatment · Capitol Hill moss removal · recurring packages · pricing guide