Deck Waterproofing & Flashing in Shoreline, WA
Waterproofing and flashing repair for decks, balconies, windows and roof-to-wall joints. When coatings wear through or flashing is missing at doors and walls, the leak often shows up far from where water gets in. We trace it to the source, replace any wet framing, correct slope and flashing, and finish with a walkable surface that drains away from the house. We serve homeowners across Shoreline and nearby Seattle and Lake Forest Park.
Before
AfterNew siding and trim around the window
Why waterproofing comes up so often in Shoreline
Older Shoreline homes were built before kick-out flashing and window sill pans were standard, and that missing metal causes a lot of hidden rot. Where a roof edge dies into a wall, water runs down behind the siding every storm. Decks attached without ledger flashing let rain into the rim joist. On newer townhomes near the light rail stations, balcony membranes and door thresholds are the weak spots. We add or replace flashing, pans and membranes during repairs so water drains out instead of soaking in.
Shoreline is mostly a postwar city. Neighborhoods like Ridgecrest, Briarcrest, Parkwood and Meridian Park filled in during the 1950s and 60s with ramblers, split-levels and daylight basement homes on generous lots. Many still have original cedar or hardboard lap siding, single-pane windows long since replaced without new flashing, and attached decks added in the 70s or 80s. Richmond Beach and Innis Arden have larger custom homes, some with view decks toward Puget Sound. Newer townhomes and apartments are rising near the light rail stations and along Aurora Avenue, which brings modern siding systems into a city of mostly older houses.
Shoreline’s west side faces Puget Sound, and storms coming down the Sound drive rain hard into west and south walls near Richmond Beach and Innis Arden. Inland, the challenge is shade and damp rather than wind. Mature evergreens, ravines along Boeing Creek and Thornton Creek, and wet winters keep decks and lower siding damp for months. Low-slope roofs on 1950s ramblers shed water close to the walls, and short eaves give siding little protection from steady rain.
Our crew comes out from our Woodinville office, and we also work in nearby Seattle, Lake Forest Park, Edmonds and Mountlake Terrace.
When to call about waterproofing in Shoreline
- Stains or drips on the ceiling below a deck or balcony
- Rot or stains under windows and doors
- Cracked, peeling or soft deck coating
- Water pooling against the house after rain
- A deck that slopes toward the house
Our waterproofing process, step by step
Trace the leak
Moisture readings, inspection openings and photos to find the real source.
Repair the substrate
Rotted plywood, joists or sheathing are replaced before sealing.
Correct slope and details
Proper slope, sill pans and flashing at every edge and door.
Apply the system
Primer, membrane and walkable top coat applied in layers.
Water test
We test the problem areas and show you the finished details.
Recent waterproofing projects near Shoreline
What we do in Shoreline
Kick-out flashing
Diverts roof water away from the wall at roof-to-wall joints.
Walkable deck coatings
Waterproof coating systems for decks and balconies over living space.
Window head flashing
Flashing and tape around windows to stop leaks into the wall.
Slope correction
Fix flat or back-sloped decks so water drains away from the wall.
Leak investigation
We trace leaks to the source before anything is sealed.
Door and sill pans
Pan flashing under doors, where many balcony leaks start.
Neighborhoods and permits in Shoreline
Richmond Beach and Innis Arden sit on bluffs above the Sound, so wind exposure and salt air wear down paint, flashing and deck railings fastest there. Ridgecrest and North City are flatter and more suburban, with rot driven by age and short eaves. Echo Lake and Ballinger-area streets near Lake Ballinger see more morning dampness. Lots bordering Shoreview Park and the Boeing Creek ravine stay shaded and mossy, especially on north-facing walls.
Simple like-for-like repairs often don’t need a permit in Shoreline, while structural work, new decks, and larger siding or window replacements usually do. Permits are issued by the City of Shoreline. We check with the City of Shoreline before starting so the scope, the paperwork and the inspections are all lined up.
Deck and balcony surface options
| System | Best for | Expected life | Maintenance |
|---|---|---|---|
| Recoat existing membrane | Sound surface with a worn top coat | A few years per top coat | Keep drains clear, recoat when worn |
| New walkable membrane | Decks and balconies over living space | 10–15+ years | Top coat every few years |
| Membrane under decking | Dry space under a deck with a wood or composite surface | 15+ years | Keep gaps and drains clear |
| Rebuild, slope and membrane | Wet or rotted plywood, flat or back-sloped deck | 15+ years | Top coat every few years |
What waterproofing typically costs in Shoreline
| Project | Typical scope | Price range | Timeline |
|---|---|---|---|
| Flashing repair | Kick-out, head flashing or a door pan at one spot | $600 – $2,500 | 1 day |
| Recoat a balcony | Prep and top coat over a sound membrane | $1,500 – $4,500 | 2–3 days |
| New walkable membrane | Full membrane system on a deck or balcony | $5,000 – $14,000 | 4–7 days |
| Rebuild and waterproof | New plywood, slope correction, flashing and membrane | $12,000 – $30,000+ | 1–3 weeks |
These are typical 2026 ranges we see for waterproofing in Shoreline and nearby cities. Your price depends on what we find once the area is open, access and height, and the materials you choose. Every estimate is free, in writing and based on an on-site inspection with photos.
Waterproofing in Shoreline: cost and timing
Most common causes
Worn deck coatings
Coatings wear through first at doors, edges and posts, and water reaches the plywood underneath.
Doors without sill pans
Water that gets under a threshold runs into the subfloor and the room below.
Missing kick-out flashing
Roof water runs down the wall instead of into the gutter and soaks the siding and framing.
What drives the price in Shoreline
Waterproofing in Shoreline depends on the size of the deck or balcony, how much substrate has to be replaced, slope correction and how many doors and walls need new flashing. Recoating a sound surface costs far less than rebuilding a wet one. You get a written price after we trace the leak.
Typical timeline
A recoat over a sound deck usually takes a few days including cure time. Rebuilding plywood, slope and flashing takes about one to two weeks, depending on weather.
Backed by a 24-month workmanship warranty
Written scope
You know exactly what is included before work starts, with photos of what we found.
Our own crew
The people who quote your job are the people who do it, start to finish.
Clean site daily
Debris is hauled away and your yard is left the way we found it.
24 months covered
If our workmanship fails within two years, we come back and make it right.
What homeowners near Shoreline say
“Very professional, quick to respond, and able to schedule the work on short notice they treated our home and deck with care and did an excellent job. I would definitely hire them again for a future project.”
“One of my windows leaked after I had them cleaned and so I called Eco Home Repair to take a look. I really appreciated the thorough inspection - they determined the leak was unique to the aggressive window washing and wouldn't happen in regular rain (it had…”
“I had a great experience working with Eco Home Repair on a water damage project. Water was leaking into the house through the chimney, which caused mold and water damage issues. Eco Home Repair handled everything smoothly and professionally. They replaced the…”
5.0 average from 106 reviews on Google, Thumbtack, Angi, HomeAdvisor and Yelp. Read our reviews on Google.
Questions Shoreline homeowners ask about waterproofing
Do you repair view decks in Richmond Beach and Innis Arden?
Can you coat over my existing deck in Shoreline?
How long does a deck coating last?
Do you fix leaks around windows?
How often should a deck coating be recoated?
More from our crew in Shoreline
Waterproofing near Shoreline
Tell us about your waterproofing project in Shoreline
- Licensed, bonded & insured
- Free on-site estimates
- 24-month workmanship warranty
Book a free waterproofing inspection in Shoreline
We inspect the damage on-site, show you photos of what we find and give you a written price before any work starts.