What Crawl Space Work Costs in Tacoma, WA
Planning ranges for encapsulation, vapor barriers, insulation, moisture and mold cleanup, and structural repair in Pierce County, and the things that move a quote.
The Ranges
Full crawl space encapsulation in Tacoma costs about $6,000 to $14,000 for a typical 1,000 to 1,500 square foot crawl space; a plain vapor barrier replacement about $1,500 to $4,000. Standing water, rodent contamination, damaged framing, and low clearance each push the total higher.
| Job | Planning range* | When it applies |
|---|---|---|
| 6-mil vapor barrier replacement, with cleanout | about $1,500 – $4,000 | Dry crawl space; ground cover missing or torn |
| Reinforced 12–20 mil liner, vents left open | about $3,000 – $7,000 | Dry crawl space; a barrier that will survive service traffic |
| Full encapsulation, 1,000–1,500 sq ft | about $6,000 – $14,000 | Sealed liner, closed vents, dehumidifier, radon provision |
| Full encapsulation, small or large | from about $4,500 / up to about $18,000 | Under 800 sq ft, or over 1,800 sq ft and wet |
| Crawl space dehumidifier, installed | about $1,200 – $2,500 | Any closed-vent crawl space |
| Interior perimeter drain to a sump | about $1,500 – $5,000 | Standing groundwater on till ground |
| Sump pump and basin | about $1,200 – $3,500 | Battery backup adds about $600 – $1,500 |
| Floor insulation removal and R-30 replacement | about $2,000 – $5,000 | Tacoma Power rebate of $750 where eligible |
| Mold cleanup | about $2,000 – $7,000 | After the water source is stopped |
| Rodent contamination cleanup | about $2,000 – $5,000 | Common in pre-1980 neighborhoods |
| Structural: post and footing / joist sister / sill per foot | about $800 – $2,500 / $150 – $350 / $100 – $200 | See the repair page |
*Planning ranges built from published regional per-job and per-square-foot figures, not quotes. The crawl space companies that rank for these searches do not publish prices on their Tacoma pages, as far as this site could check in September 2026, so these numbers are here to make a quote readable rather than to replace one. The inspection sets the real figure.
What Moves the Number Under a Tacoma House
Standing water
The biggest swing. A dry crawl space gets a liner; a crawl space with groundwater on hardpan gets a drain, a sump, and a discharge line before the liner, which adds roughly $2,500 to $8,000. Contractors who quote from the driveway miss it, and contractors who inspect in July can miss it too, which is why the water line on the stem wall matters more than the date of the visit.
Rodents and contamination
Rats and mice are in a large share of Tacoma's older crawl spaces, and their cleanup is protective-equipment work priced on its own. A fouled crawl space adds about $2,000 to $5,000 before a sheet of plastic goes down, and skipping it leaves the smell sealed under the new liner.
Clearance and access
An 18-inch crawl space with ducts and plumbing across it takes about twice as long to work in as a 36-inch one, and some Tacoma hatches are too small to pass a dehumidifier. Low clearance shows up on every line of the quote.
What is already damaged
Rotted posts, a soft sill, and delaminated subfloor are found on the inspection or found later. Found on the inspection they are a line on the quote; found later they are a change order at a worse rate. See structural repair for what each costs.
Rebates
Tacoma Power pays $750 toward crawl space floor insulation reaching R-30 on electrically heated homes it serves, through a participating contractor. It pays nothing toward the liner, the drainage, or the cleanup.
Reading a Crawl Space Quote
- It states the liner thickness in mil, the seam treatment, and how far up the wall it runs.
- It says what happens to the water: drain, sump, discharge point, and whether the pump has a backup.
- It says what happens to the air once the vents are closed: the dehumidifier and where it drains, or the conditioned supply.
- It addresses radon if the crawl space will be unvented, because the state code does.
- It lists the insulation R-value going back in and whether the old insulation is coming out.
- It says whether posts, sills, and joists were inspected and what was found.
- It names any permit the work needs and who pulls it.