Home Remodeling in
Chehalis, WA
Chehalis has lived with its river for as long as it has existed. The building rule that follows from that is simple: in the flood zone, you raise a home, you do not seal it.
Remodeling in Chehalis
What building in Chehalis actually involves
Chehalis is the Lewis County seat, just south of Centralia on the Chehalis River. The river has flooded the town again and again, and it has closed Interstate 5 through Chehalis more than once, including for several days in 2007 when the highway sat under as much as ten feet of water.
That history is written into the building rules. If your home is in a flood zone, it shapes what a remodel or an addition can look like before anything else does.
Elevate, do not floodproof
New construction in a Chehalis flood zone has to be elevated at least one foot above the base flood elevation. The city sets its flood protection elevation at base flood elevation plus one foot, or plus three feet for critical facilities.
What you cannot do with a house is seal it instead. Under the National Flood Insurance Program, floodproofing residential buildings is not permitted, apart from a narrow FEMA exception for floodproofed basements. For a home in the flood zone, raising the living space is the route, not waterproofing it where it stands.
When a remodel pulls in the flood rules
Chehalis records the elevation of the lowest floor, including any basement, for new and substantially improved buildings in the flood zone.
Substantial improvement is a federal term. It covers reconstruction, rehabilitation or additions whose cost reaches 50 percent of the building's market value measured before construction begins. Below that threshold, an existing home is not required to meet current flood standards. At or above it, the entire building is.
So in Chehalis the project budget is also a design decision. Two versions of the same remodel can land on either side of that line, with very different consequences.
Before you plan
Elevation certificates are usually required for buildings located in the flood zone, and they are used for flood insurance. If you do not have one for your home, it is worth getting before design starts.
Flood zone and permit questions go to the City of Chehalis Building Department on (360) 345-2229.
City requirements on this page were last checked on 13 September 2026. Codes change, so confirm current standards with the city before you apply.
What We Build
Our services in Chehalis
Client Reviews
What our clients say
“Chris and his crew are very friendly and professional. They did an awesome job. The house looks great. They made sure all garbage and paint was cleaned up. Very pleased with this company. Would use them again.”
Exterior painting
“We were at the beginning stages of some external home refresh work and Thomas helped us get educated on some recommended next steps based on their free consultation. It was very helpful and it gave me the confidence to continue with the project. Thomas was very professional and gave a full assessment of our project areas in a quick a precise manner. We look forward to hiring KOI Build Co for future home projects.”
Common Questions
Remodeling in Chehalis, answered
Can I floodproof my house in Chehalis instead of raising it?
Generally no. Floodproofing of residential buildings is not permitted under the National Flood Insurance Program unless FEMA has granted the community an exception for floodproofed basements. Homes in the flood zone are elevated instead.
How high does new construction need to be in a Chehalis flood zone?
At least one foot above the base flood elevation. The city's flood protection elevation is base flood elevation plus one foot, or plus three feet for critical facilities.
When does a remodel have to meet the flood zone rules?
When it is a substantial improvement, meaning its cost reaches 50 percent of the building's market value before construction begins, or when repairing substantial damage.
Do you work in Chehalis?
Yes. Chehalis and Lewis County are part of our service area, along with Pierce and Thurston counties. Call (253) 348-1847 for a free estimate.
Service Area
Where we work in Chehalis
More Areas
Other areas we serve
- CentraliaLewis County
- LaceyThurston County
- TumwaterThurston County
- YelmThurston County
- SheltonMason County
- TeninoThurston County
- TacomaPierce County
- LakewoodPierce County
- PuyallupPierce County
- Gig HarborPierce County
- SteilacoomPierce County
- DuPontPierce County
- SpanawayPierce County
Planning a project in Chehalis?
Free estimates, and a straight answer on what your project will cost and how long it will take.
Also serving Olympia, Tumwater and the wider South Puget Sound.