Northwest Outdoor Maintenance Outdoor Maintenance Northwest

Your Guide to Outdoor Maintenance — Northwest

If you live in the Northwest, prevent problems and preserve the value of your property with proactive outdoor maintenance.

If moss is neglected on your roof, its byproducts will make asphalt and wood shakes shingles more brittle. Apply a moss killer and sweep dead moss off the roof with a broom. Image:

Winters in the Pacific Northwest are famously rainy. The effects of a long, damp winter make routine outdoor maintenance especially critical. As weather warms, here are essential outdoor upkeep tasks you should complete.

Clear the roof of moss

“Neglecting moss can shorten the life of your roof by several years,” warns Jim Katen, a home inspector with Associated Master Inspectors in Gaston, Ore. “Moss keeps the body of an asphalt shingle soaked so it tends to get more freeze-thaw damage in the winter.”

In addition, moss produces organic byproducts that make both asphalt and wood shake shingles more brittle. Moss holds moisture against the wood, speeding rot. Moss can even crack cement or ceramic tiles.

Left unchecked, moss on an asphalt shingle roof loosens the shingles’ protective granular coating, clogs valleys, and can even cause pieces of shingles to break off. Let a 2,500 sq. ft. roof go two or three years and you can expect to pay about $700 for a professional cleaning. Ignore it longer and you may need new roofing—a cost of $7,000 to $19,000. The cost of a preventive dose of moss killer? About $20.
Begin moss eradication in the fall by applying a moss killer intended for roofs (granules for lawn use contain iron which will stain a roof). In the spring, use a broom to remove remaining dead moss. Spread moss killer along the ridge of the roof and on any remaining green patches. Cost: $20 for moss killer to treat 2,500 square feet of roof. Allow about 3 hours to sweep the roof, clear the gutters, and apply the granules.

Clean the gutters

Fir needles and broken fir boughs conspire to jam gutters and downspouts. An overflowing downspout can send water cascading down walls, carving out canyons beneath the downspout. A gutter scoop is a handy way to remove debris. Use a garden hose to flush out granules and a plumber’s snake to clear downspouts. Cost: $5 for a gutter scoop. Allow about 4 hours to clear the gutters and downspouts.

Check for carpenter ants

Carpenter ants emerge in the early spring. Look for them in areas of clutter near the house, especially woodpiles. In the crawlspace, look wherever there might be warmth—under the water heater, kitchen range, or space heaters.

You may find the ants themselves, as well as telltale piles of shavings similar to those from a pencil sharpener. It’s possible to get rid of a small infestation by applying insecticide powders and gels, but pros know how to get to the nests to truly eradicate the problem. Cost: $40 for powders or gel.

Allow as much time as necessary to clear away woody debris that harbors the ants. Make sure soil and mulch is at least 6 inches away from any siding and trim. Clearing debris hinders termite infestations as well. However, short of finding piles of old wings or seeing swarms emerge, it’s difficult to detect termites. If you suspect an infestation, call in a pro.

Inspect sprinkler systems & hose bibs

If you have a lawn sprinkler system, turn on your system and check for damaged or misdirected heads. Look for puddles, a sign that there’s a leak in the system. Check for dry areas, too; you may have a blocked pipe that needs flushing, or a kinked supply line. Cost: $3 to $15 per replaced head, $2 to $5 for a coupling to repair a leak. Allow a couple of hours to check the system.

If a hose bib was left undrained and unprotected through the winter, the pipe may have frozen and cracked, creating a leak in the wall or crawlspace. Repair the pipe and install a frost-proof hose bib or inside shutoff for draining. Cost: About $15 for a frost-proof hose bib. Plan on 2 to 4 hours to make the replacement.


Plants never stop growing in the temperate Northwest. Before you know it, they may be crowding your house, creating ideal conditions for mold growth and, eventually, rot. Trim back bushes and trees until there is at least a 3-foot gap between the plantings and the house. Cost: $15 for a pruning saw and $10 for pruning shears. Allow 1 to 2 hours for pruning.

Follow up by washing the siding with a light solution of bleach or TSP (trisodium phosphate). Cost: $10 for cleaners. Allow 4 to 6 hours for the job.

Wash the deck

Over the winter, a wood deck can develop a slippery scum. Use a deck wash and a good brushing to clear the stuff. Cost: About $13 per 100 sq. ft. for wood deck cleaner. If you’ve skipped a season, add $10 per 100 sq. ft. for brightener. Allow about 3 hours for the job.

If you have composite or PVC decking, now is the time for a good soap and water wash.

Moss in the grass

Not only can moss infest roofs, it can virtually take over a lawn. Apply moss killer (use the type intended for lawns, not roofs) to mossy areas. As the moss dies away (some homeowners accelerate the process by pulling out the moss with a de-thatching rake), reseed the bare spots.

The underlying culprit is soil acidity, something moss thrives on. Discourage moss and give the grass a boost by spreading pelletized lime on the lawn. Cost: $20 for moss killer for to deal with a 5,000 sq. ft. lawn, $36 for a de-thatching rake, $40 for seed to cover the bare spots, and $50 for lime. Set aside a weekend to do the job.

Fences and gates

Check fence stiles and pickets for damage and replace as needed, using galvanized fasteners. Push and pull on each post for signs of rot at its base. If the post moves easily, make sure the soil around the base is firmly packed.

If the soil seems firm and the post still moves, it’s probably rotted. Replace or repair it. For a quick fix, pound in a steel post alongside it and wrap the two with wire.

Check that gates open and close smoothly. Gate hinges and latches typically don’t wear out, but their fasteners can loosen, causing the gate to sag or be difficult to latch. Relocate them up or down a bit. Cost: $7.50 to $15 for a 5-foot cedar post; $3.50 for a steel post, $2 for wire. Allow 30 minutes for a repair.

Sidewalks and driveways

Cracks in concrete and asphalt no wider that ½-inch can be repaired with crack filler. Larger damage should be repaired with patch material. Cost: $4 for concrete or asphalt caulk. Allow a couple of hours to fill cracks. Plan on $18 for a gallon of concrete patch, $10 for asphalt patch. Allow 2 to 3 hours to repair a 2 sq. ft. area.

If a section of concrete walkway has tilted or sunk, there’s no easy DIY solution—hire a pro to hydraulically reposition the slab. Replacing a badly cracked concrete driveway can be expensive; expect to pay $4,000 to $6,000 to replace a 12 by 50-foot driveway.

If you can see light colored aggregate showing through the sealer of an asphalt driveway it’s time to recoat. Cost: $20 for enough sealer to coat 350 sq. ft. of driveway, $11 for a brush applicator. Allow about 4 hours to sweep and seal an average-size drive.