What is a rat slab?
A rat slab is a thin layer of concrete poured over the dirt floor of a crawl space. The federal Building America Solution Center, run for the Department of Energy by Pacific Northwest National Laboratory, describes it as typically 2 to 4 inches thick and says it is sometimes called a “rat slab” because it resists burrowing rodents. It is thinner than a basement floor because a crawl space is not living space and does not carry the same loads.
Rodents are not the only reason one gets poured. The same guide notes that builders use a crawl space slab to make the space usable for storage, or to make heating equipment under the house easier to reach. Whatever the reason, the slab replaces bare soil with a hard floor, and that is both what it is good for and where its limits start.
Why you hear the term around Seattle
The name is not local: the federal guide above uses it, and so do builders elsewhere. It is a term Seattle-area homeowners search for by name, though, which is why this guide exists, and it fits the rat that causes most crawl space trouble here. The Washington Department of Fish and Wildlife names two rats in the state. The Norway rat prefers to nest at or under ground level, with burrows along foundation walls, under slabs and beneath buildings, usually less than 18 inches deep and about 3 feet long. The roof rat nests in attics, trees and vines and rarely digs. A rat that tunnels under a foundation and comes up through bare crawl space soil is the problem a concrete floor answers.
Older houses are where people tend to find one already in place, or wish they had. Public Health — Seattle & King County puts the duty to keep rats out on the property owner, and its advice for keeping them out begins with sealing every gap and hole. A slab is one way to close the biggest opening a crawl space has: the whole floor.
What a rat slab stops, and what it does not
Burrowing rodents: yes, from below
A continuous slab that meets the foundation wall all the way round takes away the soil a Norway rat digs through. The Department of Fish and Wildlife explains why concrete works where softer materials do not: the inward curve of a rat’s front teeth makes it hard to gnaw into a flat, hard surface, but given an edge or a rough spot, rats can quickly gnaw into most materials. That is the catch. A slab with cracks, broken edges, gaps at the foundation wall or holes around pipes gives them exactly that edge.
Rats can also go deeper than the slab. The Building America Solution Center reproduces a design measure for exactly that: a vertical curtain wall of corrugated metal, concrete or brick, extending 2 feet down and 8 to 12 inches out, to stop rats burrowing under crawl space foundations. A slab inside the foundation does not stop a rat that tunnels under the footing and comes up through a gap at the edge.
Rodents through the walls and vents: no
A slab covers the floor. It does not touch the foundation vents, the gaps around plumbing and wiring, the access hatch or the sill above, and those are where most rodents get in. CDC’s list of places to check names crawl space vents and the joint where the foundation meets the ground; Public Health — Seattle & King County says rats squeeze through holes the size of a quarter and mice through holes the size of a dime. Exclusion work at those points is needed with or without a slab, and the guide to rodents in a crawl space sets out the order it goes in.
Ground moisture: not by itself
This is the point most rat slab sales pitches skip. The Building America guide says plainly that a concrete slab alone will not prevent moisture coming up into the crawl space from the ground. Concrete is porous, and it draws water up through its pores and hairline cracks by capillary action. Without a break under it, the guide says, moisture can wick up through the slab into the crawl space, which can lead to mold and moisture damage. Its fix is a sheet of polyethylene, at least 6 mil, laid over the ground before the pour, with seams lapped 6 to 12 inches and sealed and the sheet sealed around posts, pipes and the walls. It also warns against the habit of putting a layer of sand between the sheet and the concrete: the sand soaks up water from the fresh concrete and then dries slowly into the crawl space for a long time.
So two rat slabs that look the same from the hatch can behave very differently. One poured over a sealed sheet keeps soil moisture out; one poured straight on the dirt can leave the crawl space as damp as bare soil would. If you are buying or inheriting a house with a slab, nobody can see from above which one it is; ask for records, and watch for the signs in the section on living with an old slab below.
Radon: not by itself
Radon is a soil gas, and a slab is not a radon system. Washington’s code treats radon as a separate requirement with its own hardware: where a crawl space is built with reduced ventilation or with operable louvers, or is built sealed, the code requires a radon vent or radon system from under the ground cover, built to its radon appendix. The Building America guide, likewise, puts any radon vent pipe under the polyethylene before the slab is poured, not in place of it.
For perspective, King and Snohomish counties are in Zone 3, EPA’s lowest radon category. EPA and the Washington State Department of Health both say every home should still be tested, and the department adds that a test taken in a crawl space says little about the exposure of the people living above it. Test the rooms you use.
Rat slab, liner, encapsulation or exclusion?
These four get quoted against each other as if they did the same job. They do not, and the right answer is often two of them together.
| Rat slab | Ground cover (vapor barrier) | Encapsulation | Exclusion | |
|---|---|---|---|---|
| What it is | Concrete, typically 2 to 4 inches, over the soil | Polyethylene sheet over the soil; 6-mil black poly is Washington’s baseline | A sealed Class I liner carried up the walls, with Washington’s radon and exhaust conditions | Sealing vents, penetrations, the hatch and gaps at the foundation |
| Burrowing from below | Stops it where the slab is whole and meets the walls | No; rats chew and dig through plastic | No more than the liner itself | No, unless it includes a below-grade barrier |
| Entry through vents and gaps | No | No | Closes the vents; penetrations still need sealing | Yes; this is what it is for |
| Ground moisture | Only with a sealed sheet underneath | Yes, if intact and lapped | Yes | No |
| Vents | Still required | Still required | Replaced by continuous exhaust | Screened, not closed |
| Takes up height | Yes, the thickness of the slab and any base | No | No | No |
| Easy to repair or remove later | No | Yes | Yes, with care | Yes |
In practice: where rats are coming up through the soil, a slab over a sealed sheet answers that and covers the ground in one job, and exclusion is still needed at the walls. Where the trouble is damp air, bare dirt or a torn old sheet, a vapor barrier or encapsulation does the moisture job with far less disruption, and exclusion closes the routes in. Whichever way you go, the space gets cleared first: crawl space cleaning covers the debris, droppings and old insulation that come out before anything is poured or laid.
What Washington’s code says about a rat slab
Washington adopts the 2021 International Residential Code with its own amendments, and its section on the space under a house, R408, is in WAC 51-51-0408. Seattle’s version of R408 reads the same. Four points matter for a slab.
- A slab can stand in for the ground cover, and nothing else. R408.1 requires a ground cover of 6-mil black polyethylene or an approved equal over the soil of a crawl space, lapped 6 inches at the joints and extended to the foundation wall. Its exception: the ground cover may be omitted where the crawl space has a concrete slab floor at least 2 inches thick. That is the whole of what the code says about a crawl space slab. It does not ask for a sheet under the slab; the federal guidance above does, for moisture reasons.
- The vents stay. The same section requires ventilation openings through the foundation or exterior walls, at 1 square foot per 300 square feet of under-floor area, and the slab exception does not change that. Closing the vents is a separate route, R408.3, with its own conditions: a continuous Class I vapor retarder sealed 6 inches up the stem wall, a radon system, and continuous exhaust ventilation at 1 cfm per 50 square feet. R408.3 is written around covering exposed earth and does not mention a slab, so how a sealed crawl space over an existing slab is treated is a question to put to the building department.
- Access and clearance still apply. The model code sections Washington leaves unamended require an access opening of at least 18 by 24 inches through the floor or 16 by 24 inches through a perimeter wall, and the ground under the floor cleared of vegetation, organic material, forms and construction scraps. A slab poured over debris breaks the second rule. It also takes height, which matters more than it sounds: Washington’s home inspection rules let an inspector decline to enter a crawl space with less than 18 inches under the joists or 12 inches under the girders, so a slab that brings a low crawl space under those figures can make it one nobody inspects.
- Grade and drainage. Where groundwater can rise to within 6 inches of the finished floor at the perimeter, or surface water does not drain readily, the code wants the under-floor grade at least as high as the outside grade unless an approved drainage system is provided. A slab does not fix a crawl space that floods; standing water in a crawl space covers that first.
Permits. In the City of Seattle, the residential code’s permit exemptions name insulating existing buildings and in-kind repair of deteriorated members, and exempt minor repairs valued at $6,000 or less in any six months where no loadbearing support is altered and ventilation is not reduced. They do not name a crawl space slab, so whether a given pour needs a permit is the building official’s call; ask the Seattle Department of Construction and Inspections before the work starts. In unincorporated King County, crawl space work is not on the county’s list of work that needs no permit. Each other city sets its own rules.
Living with an old rat slab
Many of the slabs people ask about were poured decades ago, by someone else, to a standard nobody wrote down. What to look at:
- Gaps at the edges. Where the slab meets the foundation wall, piers and pipes is where a rat finds the edge it needs to gnaw, and the Department of Fish and Wildlife warns that settling opens new gaps over time. Fresh soil pushed up through a crack or at the wall means animals are still coming from below.
- A damp surface or a musty smell. A slab that darkens in patches, sweats in wet weather or carries mold on whatever sits on it may have been poured straight on the dirt. The Building America guide’s point about capillary rise is the likely explanation. The guide to high humidity in a crawl space explains how to read the air.
- Debris on top. A slab is easy to treat as a storage floor. Wood, cardboard and old insulation on concrete in a damp space are food and cover for pests and fungi, and the code expects the space clear.
- Height. Measure from the slab to the bottom of the joists and the girders. Under 18 and 12 inches, inspections get harder to come by.
- Records. If you are buying, ask whether a sheet went under the concrete and whether a radon pipe was set beneath it. A seller may not know; it is still the right question.
A slab that is cracked, damp or full of debris is not necessarily a slab to break out. Sealing the edges and penetrations, clearing the surface and, where moisture is the problem, covering the slab or correcting the water source are usually the first options to price.
What does a rat slab cost?
This site publishes no price range for a rat slab. There is no pricing model behind one, and a range without one would be a guess. The job varies a great deal with the size of the crawl space, the clearance, how the concrete is moved under the house, what has to be cleared first, and whether a sheet, a radon pipe or edge sealing is part of the scope. What a written quote should state:
- the slab thickness, and the area it covers;
- what goes under the concrete: the polyethylene, its thickness, how seams and edges are sealed, and confirmation that no sand layer goes between sheet and slab;
- whether a radon vent pipe is installed under the sheet;
- how the slab is finished at the foundation wall, piers and pipes, and what exclusion work at the vents and penetrations is included;
- clean-out of debris, droppings and old insulation before the pour, and how contaminated material is handled;
- the clearance left under the joists and girders when it is done.
For the alternatives, the site does publish modeled ranges: a vapor barrier at $3,400 to $4,675 and full encapsulation at $10,650 to $13,000 for a typical Seattle-area crawl space, before sales tax (10.55% in Seattle). The cost guide sets out what each covers and how the ranges are produced.
Who does the work
Pouring a slab under a house is construction work, and in Washington anyone contracting for it must be registered with the Department of Labor & Industries, bonded and insured. L&I’s specialty classifications include a concrete specialty that covers placing film barriers as well as concrete, and a structural pest control specialty for vent screens, exclusion devices and caulking; no classification names crawl space work as such. Treating rodents with poison or other pesticides is a separate Department of Agriculture license. How to verify a Washington contractor shows where to check the registration.
If you want the crawl space looked at before deciding between a slab, a liner and exclusion, you can request a free in-home inspection and get a written, no-obligation quote. A useful one says how rodents are getting in, what the moisture is doing, and which of the options above answers each, line by line.
Sources
What a rat slab is, why a slab needs a sheet under it and the advice against a sand layer are from the Building America Solution Center; rat behavior is the Washington Department of Fish and Wildlife’s; entry sizes are Public Health — Seattle & King County’s and CDC’s. Code points are from WAC 51-51-0408, WAC 51-51-0332 and Seattle’s 2021 residential code; radon zones and testing advice are EPA’s and the Washington State Department of Health’s. This site publishes no price for a rat slab, and no one from this site has seen your crawl space.
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U.S. Department of Energy, Building America Solution Center (Pacific Northwest National Laboratory), Capillary Break at Crawlspace Floor - Polyethylene Sheeting under Concrete Slab (Building America Solution Center guide, last updated 2017-03-14) Checked
That some builders pour a thin concrete slab, typically 2 to 4 inches thick, on a crawl space floor, which can make the space usable for storage or ease access to equipment, and that it is sometimes called a “rat slab” for its resistance to burrowing rodents; that a slab alone will not stop moisture coming up from the ground, because concrete wicks water through its pores by capillary action, which can lead to mold and moisture failures; that the guide calls for polyethylene sheeting of at least 6 mil over the ground before the pour, seams lapped 6 to 12 inches and sealed, sealed around posts and pipes and at the walls; that no sand layer should go between the polyethylene and the slab, because the sand holds water from the concrete and dries slowly into the crawl space; and that a radon vent pipe, where wanted or required, is installed under the sheeting before the slab, and a two-inch slab can be poured over the sheeting of a radon system to make it more durable.
Note: Federal construction guidance for new houses, not a code. It describes how to build a slab well; it does not measure how often older slabs were built with a sheet underneath.
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U.S. Department of Energy, Building America Solution Center (Pacific Northwest National Laboratory), Construct a vertical curtain wall … to prevent rats from burrowing under crawlspace foundations (Building America Solution Center image record, citing San Francisco Department of the Environment, Pest Prevention by Design) Explanatory summary, not the governing text Checked
That a vertical curtain wall of 29-gauge corrugated iron, concrete or brick, extending 2 feet down and 8 to 12 inches out, is a design measure to stop rats burrowing under crawl space foundations.
Note: A one-line design recommendation the Solution Center reproduces from a San Francisco pest-prevention guide; cited for the measure, not as a requirement anywhere in Washington.
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Washington Department of Fish and Wildlife, Living with wildlife: Rats Checked
That the Norway rat and the roof rat are the two rats found in Washington; that Norway rats prefer to nest at or under ground level, and their burrows are found along building foundation walls, under slabs and beneath buildings, typically less than 18 inches deep and 3 feet long with entries 2 to 4 inches across; that roof rats nest in attics, trees and vines and rarely burrow; that rats destroy insulation and make noise in attics, walls and crawl spaces; that a rat needs only a 1/4-inch hole to chew larger and squeeze through, and openings should be sealed with 1/4-inch hardware cloth, metal flashing, mortar or concrete patch (steel wool corrodes once wet); that the inward curve of a rat’s incisors makes it hard to gnaw a flat, hard surface but an edge lets it into most materials; that the most successful long-term control is to build rats out; and that rats can burrow under an unprotected structure at any time and settling opens new gaps, so new signs should be watched for.
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Public Health — Seattle & King County, Rats and Mice (fact sheet) (Updated 07/30/18) Checked
That rats can squeeze through holes the size of a quarter and mice through holes the size of a dime; to fill holes with steel wool or cover them with 1/4-inch hardware cloth, metal, concrete or wood; to use wooden snap traps indoors and not glue or live traps; to air a space out for at least 30 minutes before cleaning, wear disposable gloves and never sweep, vacuum or stir up dry dust where rodents have been; to spray droppings and nests with disinfectant or a solution of 1/4 cup bleach to 2 1/4 cups water and let it sit five minutes before wiping up and double-bagging; and that hantavirus is spread only by deer mice in western Washington.
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Public Health — Seattle & King County, Preventing rodents and keeping them away Checked
That in King County it is the property owner’s responsibility to prevent conditions on the property that attract rodents; the advice to check inside and outside the house for gaps and holes; and that the department points to CDC’s guidance for cleaning up after rodents rather than publishing its own. Also, read 2026-11-11: that the best trap indoors is the wooden snap trap baited and set near droppings, and poisons are not recommended for rat control inside buildings because poisoned rats die in hard-to-reach places and smell; that firewood should be stacked 18 inches off the ground and bushes, vines and branches kept 3 feet from the house, since roof rats get in from branches over the roof; that heavy infestations may be too extensive to control alone and Public Health then recommends a professional pest control company, asking about integrated pest management; that some crawl space and attic companies also offer pest control; and that pest control companies should be licensed with the Washington State Department of Agriculture.
Note: King County only. Snohomish County’s health department does not run a pest program.
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U.S. Centers for Disease Control and Prevention, How to Seal Up to Prevent Rodents (Healthy Pets, Healthy People — Rodent Control) Checked
That a mouse passes through an opening the width of a pencil — 1/4 inch, or 6 mm — and the list of places to inspect, which names crawl space vents and the foundation-to-ground joint explicitly.
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Washington State Legislature, WAC 51-51-0408 — Section R408, Under-floor space (Washington State Residential Code, amended by WSR 23-23-104) Checked
What Washington requires under a house: ventilation at 1 square foot per 300 square feet of under-floor area; 6-mil black polyethylene ground cover with joints lapped 6 inches, extending to the foundation wall, which may be omitted where the crawl space has a concrete slab floor at least 2 inches thick; vent coverings with a least dimension of no more than 1/4 inch (corrosion-resistant wire mesh at 1/8 inch), and operational louvers permitted; ventilation reducible to 1/1,500 where a Class I vapor retarder covers the earth, with a radon vent built to Appendix AF required where ventilation is below 1/300 or operable louvers are installed. Vents may be omitted only where both numbered conditions of R408.3 are met: a continuous Class I vapor retarder lapped and sealed 6 inches, extending 6 inches up and sealed to the stem wall, with an Appendix AF radon system; and continuously operated mechanical exhaust at 1 cfm per 50 square feet. R408.8 is not adopted in Washington.
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Seattle Department of Construction and Inspections, 2021 Seattle Residential Code, Chapter 4, Foundations (Section R408, pages 4-47 and 4-48) Checked
Two things. First, that Seattle’s R408.1, R408.2 and R408.3 carry the Washington-amendment marker and read the same as WAC 51-51-0408, apart from “Appendix F” where the state rule says “Appendix AF”; the copy shows the model code’s wording struck through, including its menu of alternatives for an unvented crawl space (dehumidification, conditioned supply air, perimeter-wall insulation), which is how the two numbered conditions of R408.3 are read as applying together. Second, the sections Washington does not amend, R408.4 to R408.6: an access opening not smaller than 18 by 24 inches through the floor or 16 by 24 inches through a perimeter wall; the under-floor grade cleared of vegetation and organic material, and forms and construction materials removed; and the under-floor grade as high as the outside finished grade where groundwater can rise to within 6 inches of the finished floor at the perimeter or surface water does not drain readily, unless an approved drainage system is provided.
Note: The PDF marks additions by underline, which is lost when its text is extracted. “No Seattle-only change to R408” is drawn from the match with the state rule, not from a statement by the city. R408.4 to R408.6 are model code text and are summarised here, not reproduced.
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Washington State Building Code Council (via Washington State Legislature), WAC 51-51-0332 — Section R332, Protection against radon Checked
Where the radon appendix applies. R332.1: to buildings constructed in the high radon potential (Zone 1) counties of Table AF101(1), and also to all buildings constructed using the unvented crawl space method of Section R408.3, in any county.
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Seattle Department of Construction and Inspections, 2021 Seattle Residential Code, Appendix F, Radon Control Methods (Section AF103.5, page AF-9) Checked
What the radon appendix asks for under a crawl space. AF103.5 describes a passive sub-membrane depressurization system: a continuous soil-gas retarder of polyethylene at least 6 mil thick, lapped not less than 12 inches and extended to the foundation walls, with a 3- or 4-inch vent pipe run from beneath the sheeting up through the building to at least 12 inches above the roof. The section has an exception for buildings with an approved mechanical crawl space ventilation system or equivalent.
Note: Model code text read in the city’s copy and summarised, not reproduced. The appendix asks for 12-inch laps of the soil-gas retarder where R408.3 asks for 6-inch sealed laps of the vapor retarder; which governs on a sealed crawl space is a question for the building department.
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U.S. Environmental Protection Agency, EPA Map of Radon Zones — Washington Checked
That King and Snohomish counties are in Zone 3, EPA’s lowest of three radon categories (predicted average indoor screening level below 2 pCi/L); Zone 2 is 2 to 4 pCi/L and Zone 1 is above 4. Washington’s Zone 1 counties are Clark, Skamania, Okanogan, Ferry, Stevens, Pend Oreille and Spokane. A low zone does not remove the Appendix AF radon vent that WAC 51-51-0408 requires where crawl space ventilation is reduced or the crawl space is built unvented.
Note: EPA states the map must not be used to decide whether an individual home needs testing, and that every home should be tested regardless of zone. A county-level prediction says nothing about one building.
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Washington State Department of Health, Radon Checked
That the department lists fixing or installing a crawl space vapor barrier, and keeping foundation vents unobstructed, among simple steps that reduce radon, and that a test taken in a crawl space says little about the exposure of the people living above it.
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Washington State Department of Licensing (via Washington State Legislature), Chapter 308-408C WAC — Home inspectors: standards of practice (As amended by WSR 26-15-037, effective August 7, 2026) Checked
What a Washington home inspection is required to cover at a crawl space, and what it is not. WAC 308-408C-010: an inspection uses visual observation, simple tools and normal controls, is not technically exhaustive, and the inspector is a generalist who identifies conditions that may need a specialist. WAC 308-408C-030(1): inspectors are not required to determine the strength, adequacy, effectiveness or efficiency of a system or component, the causes of any condition or deficiency, the methods, materials or estimated cost of repairs, or future conditions; (2) nor to comment on compliance with codes; (3) nor to report wood destroying insects or environmental hazards including mold; (18) nor to enter flooded crawl spaces. The same section says an inspector who is qualified and willing may specify the type of repairs to be made. WAC 308-408C-070: the inspector enters and traverses crawl spaces where readily and safely accessible, inspects visible foundations, posts, piers, beams, joists and subfloors and looks for signs of flooding and moisture penetration, probes where deterioration is suspected, and reports all wood rot and pest-conducive conditions, but need not enter a crawl space that requires excavation, has an access opening under 18 by 24 inches, or has less than 18 inches of headroom under joists or 12 inches under girders. WAC 308-408C-100: reports the presence and functionality of sump pumps when visible. WAC 308-408C-150: reports missing or inadequate vapor barriers in crawl spaces with earth floors and missing insulation where visible, and need not determine the thickness or R-value of insulation below floors. WAC 308-408C-050: the pre-inspection agreement must say the inspection does not include mold, asbestos, air quality or other environmental issues unless agreed in writing. WAC 308-408C-020(8): for one year after an inspection, the inspector and the inspector’s firm may not repair, replace or upgrade components of that building for pay. Also: the reason any item normally inspected is excluded must be stated in the report (030); the report may not be disclosed without the client’s approval (020(10)); and conditions beyond the inspection are referred to a specialist (070).
Note: The Washington verb in 030(1) is “determine”, and the rule permits an inspector to specify repairs. It does not bar a repair recommendation; it makes one optional.
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Seattle Department of Construction and Inspections, 2021 Seattle Residential Code, Chapter 1, Administration (Sections R105.1 and R105.2) Checked
When a building permit is needed in the City of Seattle. R105.1: a permit is required to construct, alter or repair a building, and all work must meet the code whether or not a permit is required. R105.2 item 1: no permit for minor repairs or alterations valued at $6,000 or less in any six-month period, provided no loadbearing support is removed, reduced, altered or relocated and ventilation is not reduced. R105.2 item 2: no permit, provided the building envelope is not changed, for listed work that includes insulating existing buildings and in-kind or similar replacement or repair of deteriorated members.
Note: City of Seattle only, and it is the building permit only: electrical, plumbing and side sewer permits are separate. The chapter does not say how the department classifies a ground cover, a sealed crawl space or a sump basin.
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King County Department of Local Services, Permitting Division, Do you need a permit? Checked
That in unincorporated King County the county’s Permitting Division issues building permits, that a permit is needed to construct, enlarge, alter, repair, move or demolish a building, and that crawl space work is not on the county’s list of work that needs no permit.
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Washington State Department of Labor & Industries (via Washington State Legislature), WAC 296-200A-016 — Definitions of the specialty contractor classifications Checked
The list of specialty contractor classifications, read to establish that none names crawl space work, encapsulation, vapor barriers, foundation repair, mold or radon, and for the definitions nearest to crawl space work: insulation and acoustical (insulation for the nonmechanical control of heat, sound and moisture), structural pest control (ventilation screens, exclusion devices and caulking, not pesticide work), concrete (which includes placing film barriers, sealing and waterproofing), house moving (raising, cribbing and underpinning), sanitation systems and side sewers (drains outside the building), asbestos and lead (asbestos certification required), and handyman (one person working alone on minor residential repair under $2,000 that needs no building permit).
Note: The rule defines classifications for registration only. It does not say which registration a crawl space company must hold, and this site does not state one.
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Washington State Department of Labor & Industries, Register as a Contractor Checked
That Washington requires every construction contractor to register with L&I and to be bonded and insured; that there are two classifications, general and specialty, with 63 specialties; that a specialty contractor works only in the registered specialty and cannot hire subcontractors; that plumbing, electrical, elevator, mobile home installation, boiler and asbestos work carry further education, examination and licensing requirements; the bond amounts ($30,000 general, $15,000 specialty); the liability insurance L&I asks for ($200,000 public liability and $50,000 property damage, or $250,000 combined single limit); that the bond and insurance must carry the exact business name; and that L&I suspends a registration when a bond or insurance policy lapses or a judgment goes unsatisfied.
Note: L&I’s page for contractors. The statute states the insurance minimums differently (RCW 18.27.050); this site gives both.
Sources last checked between and ; the date beside each one is when it was last opened. Where a figure comes from a document that is revised on a schedule, the edition or version is named above so you can confirm it against the current one yourself.