Deck Waterproofing & Flashing in Bothell, WA
Walkable waterproof coatings, slope fixes and flashing that keep water out of your walls and ceilings. 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 Bothell and nearby Kenmore and Woodinville.
Before
AfterFlashed and rebuilt
Why waterproofing comes up so often in Bothell
Builder-grade flashing on 80s and 90s Bothell homes is often minimal or missing, especially at deck ledgers, roof-to-wall joints and windows. Without kick-out flashing, water runs behind the siding where a roof edge meets a wall. Decks without ledger flashing let water into the rim joist. We open problem areas, repair rotted framing, and install membranes, ledger flashing, kick-out flashing and window or door pans so water sheds away from the walls.
Bothell has a small historic core around Main Street with older homes from the early 1900s, but most houses here date from the 1970s through the 2000s. North of I-405, Canyon Park, North Creek, Thrasher’s Corner and the Queensborough area are full of two-story subdivision homes with hardboard or fiber cement siding, attached decks and builder-grade trim. Westhill and Maywood have more 60s and 70s split-levels and ramblers on wooded lots. Many homes have tight side yards and backyards that slope toward greenbelts. Newer townhomes and apartments are concentrated near downtown, Canyon Park and the North Creek business parks.
Bothell sits in the Sammamish River and North Creek valleys, with hills rising on both sides. The valleys hold fog and damp air on winter mornings, while the hillsides have heavy tree cover and greenbelts that keep walls and decks shaded. Tight lot spacing in many subdivisions means side walls rarely dry out. Long, wet winters soften hardboard siding and trim, and builder-grade flashing from the 80s and 90s is reaching the end of its useful life.
Our crew comes out from our Woodinville office, and we also work in nearby Kenmore, Woodinville, Mill Creek and Lynnwood.
When to call about waterproofing in Bothell
- Streaks down the wall below a roof edge
- A deck that slopes toward the house
- Stains or drips on the ceiling below a deck or balcony
- Rot or stains under windows and doors
- Water pooling against the house after rain
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 Bothell
What we do in Bothell
Window head flashing
Flashing and tape around windows to stop leaks into the wall.
Kick-out flashing
Diverts roof water away from the wall at roof-to-wall joints.
Slope correction
Fix flat or back-sloped decks so water drains away from the wall.
Walkable deck coatings
Waterproof coating systems for decks and balconies over living space.
Door and sill pans
Pan flashing under doors, where many balcony leaks start.
Leak investigation
We trace leaks to the source before anything is sealed.
Neighborhoods and permits in Bothell
Canyon Park and North Creek on the Snohomish County side have big 80s and 90s subdivisions where hardboard siding and nailed decks are aging out. Westhill and Maywood, south of downtown, are hillier and older, with mature trees and shaded lots. Homes near the Sammamish River and in the valley get more fog and dampness. Thrasher’s Corner and Queensborough have newer homes on tighter lots, often backing onto greenbelts with heavy shade.
Small like-for-like repairs often don’t need a permit, but structural work, new decks and larger replacements usually do. Permits come from the City of Bothell for homes in both the King County and Snohomish County parts of the city. We check with the City of Bothell before starting so your project is handled correctly.
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 Bothell
| 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 Bothell 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 Bothell: cost and timing
Most common causes
Missing kick-out flashing
Roof water runs down the wall instead of into the gutter and soaks the siding and framing.
Doors without sill pans
Water that gets under a threshold runs into the subfloor and the room below.
Worn deck coatings
Coatings wear through first at doors, edges and posts, and water reaches the plywood underneath.
What drives the price in Bothell
Waterproofing in Bothell 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 Bothell say
“I hired Eco Home Repair to do a leak repair under my balcony, deck waterproofing and slope correction, and underlying rot repair. They were professional, quick, and fairly priced; kept me in the loop throughout the whole process and was honest about what…”
“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 Bothell homeowners ask about waterproofing
Why is the hardboard siding on my Bothell home swelling?
Can you coat over my existing deck in Bothell?
What is kick-out flashing?
Why is water leaking under my deck or balcony?
How often should a deck coating be recoated?
More from our crew in Bothell
Waterproofing near Bothell
Tell us about your waterproofing project in Bothell
- Licensed, bonded & insured
- Free on-site estimates
- 24-month workmanship warranty
Book a free waterproofing inspection in Bothell
We inspect the damage on-site, show you photos of what we find and give you a written price before any work starts.