Crawl Space Safety: Checklist of Unsafe Crawl Space Conditions
InspectAPedia® -
Safe procedures for inspecting building crawl spaces
When to enter or not enter a building crawl area - when is it unsafe to enter a crawl space?
List of crawl space safety hazards: shock, rodents, snakes, chemical contaminants, risk of structural collapse, mold, respiratory illness, hantavirus, asbestos exposure, etc.
List of safety procedure steps for home inspectors & electrical inspectors
Questions & answers about safety hazards in building crawl spaces
This article lists potentially dangerous or un-healthy conditions that should be evaluated by an inspector or worker who is expected to enter, inspect, or work in a crawl space anywhere in a building.
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Readers whose crawl space or basement have been flooded should also see FLOODS IN BUILDINGS-priorities. Contact Us by email to suggest changes, corrections, and additions to this material. The crawl space shown in our page top photo was in our opinion not a readily accessible area. This decision is made by the inspector on the scene, not by anyone else.
A number of conditions besides the old saw "accessibility" or size of the crawl space opening should be considered carefully by the home inspector, electrical inspector, or anyone who is deciding if it is safe to enter an crawl area anywhere in a building.
Here is a list of some safety and health considerations that the inspector should evaluate before deciding to enter a crawl space:
Is there standing water in the crawl area?
If so there is risk of electrical shock (if wiring or electrical devices are present).
There may also be a chemical contamination risk, especially in older buildings where pesticides may have been applied in the crawl area.
Is there excessive debris in the crawl area? Nails, splinters, and possibly rodents may be in the debris in our photo at left.
Are there wet crawl area floors or other surfaces? Crawling exposes a lot of body surface to the ground or other surfaces and limits movement. There maybe shock hazards or chemical hazards even if there is not actual standing water.
Beware also of evidence of structural collapse when looking at a flooded or very wet crawl space. Piers are undermined, foundations may be collapsing.
Are there chemical odors in the crawl space? If so there is an increased risk of chemical contaminants that could be hazardous. You should not enter such an area without proper protective clothing, respirator, etc.
Is there evidence of asbestos insulation, especially disturbed,damaged, or deteriorated asbestos insulation?
Do not enter such an area without protective equipment; take care that you do not track hazardous materials out of the crawlspace and into other building areas.
Often we find a crawl area in which the asbestos pipe insulation is not just hanging (photo at left) but has fallen onto the crawl space floor.
Is there evidence of mold contamination such as areas of wood, paper, or other material covered with mold or mold-suspect material. Do not enter such an area without protective gear.
Is there evidence of rodents or snakes or insect pests in the crawl space? Rodent hazards include bacterial and viral and respiratory illness; there is the obvious risk of snake bites in a confined space, and more than once we've been run out of a crawl space by bees or hornets.
But since you're unlikely to be able to move rapidly to make an emergency retreat from threatening pests, crawl areas are riskier than some other building areas.
Evidence of pests may also suggest risk of improperly applied and unsafe exposure to pesticides.
Is there sufficient space to enter and move safely in the crawl area. Review the OSHA regulations on entering confined spaces. The inspector or worker should decide if s/he a building area is safely accessible. Do not enter a confined space if you are working alone at a property. If circumstances mean you cannot avoid such an entry, be sure you carry:
A working cell phone that will function in the space
A spare flashlight
Appropriate protective gear
A camera to use for documenting conditions - it's easier than dragging along clipboards and pens.
Is there wet or falling or rodent-infested fiberglass insulation in the crawl area? If so there is a high risk of mold or rodent contaminants that could present a fungal, bacterial, or viral airborne hazard. Do not enter such an area without proper protective gear. See Mold in Fiberglass Insulation.
Is there evidence of risk of structural collapse or even structural movement in or over the crawl area?
Look closely at columns, posts, piers, girders, joists, and perimeter foundations.
It is easy to become pinned or even crushed if you enter an unstable structure.
Examples of Crawl Space Safety Gear for Entering Crawl Spaces & Mold Contaminated Areas
These suggestions are not a complete inventory of all safety procedures nor gear should be used when entering a crawl space. Contact Us by email to suggest changes, corrections, and additions to this material.
Assistant or accomplice: do not enter an unsafe or confined space alone - station an assistant at the entry and maintain contact.
Battery operated flash light and spare flash light. A spare light is important if the crawl area is large and you could be fare from the entry - to avoid being trapped in darkness if your first light fails. Dragging an extension cord and trouble light into a crawl area, powered by plugging the extension cord into a wall receptacle is dangerous unless the cord is protected by GFCI and AFCI devices.
Cell phone or two way radio - to summon help in an emergency
Eye protection - in dusty areas full coverage eye protection or goggles are most secure; in low-dust areas eye protection such as the safety glasses in our photo below have the advantage of less tendency to fog up in humid work areas.
Gloves - to protect hands especially if you need to crawl. The very thick welder's glove on our mock-up photo's right hand offers the good dry-area protection but makes it almost impossible to handle a camera or other equipment. For wet areas we wear heavy rubber padded gloves.
Knee pads - we like the gel-type knee pads shown in our mock-up photo - they make crawling easy on the knees, and their thickness keeps the legs and knees up off of damp surfaces.
Respirator, with cartridges rated for both organic chemicals and fine particulates - a HEPA filter and charcoal filter or other special filters may be required. Do not rely on a simple paper dust mask.
Head protection - depending on space this may be a hard hat or if that is impractical because of limited space, a soft padded hat may be useful. Watch out for protruding nails or other sharp objects that can poke right through a soft hat like the one we show at left. .
Questions & Answers regarding this article
Questions & answers about safety hazards in building crawl spaces
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Additional technical contributors & reference sources for this article are listed below.
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"Frequency of Occurrence and Sources of Rust and Corrosion in Electrical Panels," Daniel Friedman, IEEE HOLM Conference, Philadelphia PA, 1992 - see ELECTRIC PANEL RUST for an online version of this article.
Jim Simmons: Personal communication, J. Simmons to Daniel Friedman, 9/19/2008. Photographs contributed to this website by Jim P. Simmons, Licensed Electrician, 360-705-4225 Mr. Electric, Licensed Master Electrician, Olympia, Washington Contact Jim P. Simmons, Licensed Master Electrician, Mr. Electric, 1320 Dayton Street SE
Olympia, WA 98501, Ph 360-705-4225, Fx 360-705-0130 mrelectricwa@gmail.com
Kenneth Kruger: Original author of the sidebar on testing VOM DMM condition: Kenneth Kruger, R.A., P.E. AIA ASCE, is an ASHI
Member and ASHI Director in Cambridge, MA. He provided basis for this article penned by DJ Friedman.
"How to Use DMM's Safely," Leonard Ogden, CEE News, 888 Seventh Ave., New York, NY 10106, Dec 1990 p.10.
Dr. Jess Aronstein, consulting engineer, Poughkeepsie NY, 1991 protune@aol.com
Rex Cauldwell, master electrician and contributor to the Journal of Light Construction on electrical topics
New York State Central Hudson Gas and Electric Company, G&E/1-2/85 consumer safety pamphlet
American Society of Home Inspectors, ASHI Training Manual, Al Alk -[obsolete, and includes unsafe practices-DF]
Aluminum Wiring Information Website Aluminum Electrical Wiring Hazards and Repairs: in-depth authoritative info, photos, documents including selection of proper vs. ineffective repair methods. E.g.: Ideal 65 "Twister" purple connector fails in field and lab testing with aluminum wire.
Circuit Breaker, a bad one fails to trip failure at aluminum bus-to-circuit breaker connection - field report and photographs
Electrical Panels, How to Inspect in Buildings, safety for electrical inspectors, electrical panel, fusing, wiring defects, defective products. Inspection Class Presentation
Federal Pacific Electric (FPE) Stab-Lok Circuit Breaker Panel Hazards Website - Latent fire hazards, in-depth authoritative research, documents, advice on Stab-Lok electric panel and circuit breaker failures and what to do when this equipment is found in buildings.
"Electrical System Inspection Basics," Richard C. Wolcott, ASHI 8th Annual Education Conference, Boston 1985.
"Simplified Electrical Wiring," Sears, Roebuck and Co., 15705 (F5428) Rev. 4-77 1977 [Lots of sketches of older-type service panels.]
"How to plan and install electric wiring for homes, farms, garages, shops," Montgomery Ward Co., 83-850.
"Electrical System Inspection Basics," Richard C. Wolcott, ASHI 8th Annual Education Conference, Boston 1985.
"Simplified Electrical Wiring," Sears, Roebuck and Co., 15705 (F5428) Rev. 4-77 1977 [Lots of sketches of older-type service panels.]
"How to plan and install electric wiring for homes, farms, garages, shops," Montgomery Ward Co., 83-850.
"Home Wiring Inspection," Roswell W. Ard, Rodale's New Shelter, July/August, 1985 p. 35-40.
"Evaluating Wiring in Older Minnesota Homes," Agricultural Extension Service, University of Minnesota, St. Paul, Minnesota 55108.
"Electrical Systems," A Training Manual for Home Inspectors, Alfred L. Alk, American Society of Home Inspectors (ASHI), 1987, available from ASHI. [DF NOTE: we do NOT recommend this obsolete publication, though it was cited in the original Journal article as it contains unsafe inaccuracies]
"Basic Housing Inspection," US DHEW, S352.75 U48, p.144, out of print, but is available in most state libraries.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 2010, $69.00 U.S., is available from Carson Dunlop, and from the InspectAPedia bookstore. The 2010 edition of the Home Reference Book is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. InspectAPedia.com ® author/editor Daniel Friedman is a contributing author. Field inspection worksheets are included at the back of the volume.
Diagnosing & Repairing House Structure Problems, Edgar O. Seaquist, McGraw Hill, 1980 ISBN 0-07-056013-7 (obsolete, incomplete, missing most diagnosis steps, but very good reading; out of print but used copies are available at Amazon.com, and reprints are available from some inspection tool suppliers). Ed Seaquist was among the first speakers invited to a series of educational conferences organized by D Friedman for ASHI, the American Society of Home Inspectors, where the topic of inspecting the in-service condition of building structures was first addressed.
Design of Wood Structures - ASD, Donald E. Breyer, Kenneth Fridley, Kelly Cobeen, David Pollock, McGraw Hill, 2003, ISBN-10: 0071379320, ISBN-13: 978-0071379328 This book is an update of a long-established text dating from at least 1988 (DJF); Quoting: This book is gives a good grasp of seismic design for wood structures. Many of the examples especially near the end are good practice for the California PE Special Seismic Exam design questions. It gives a good grasp of how seismic forces move through a building and how to calculate those forces at various locations.THE CLASSIC TEXT ON WOOD DESIGN UPDATED TO INCLUDE THE LATEST CODES AND DATA. Reflects the most recent provisions of the 2003 International Building Code and 2001 National Design Specification for Wood Construction. Continuing the sterling standard set by earlier editions, this indispensable reference clearly explains the best wood design techniques for the safe handling of gravity and lateral loads. Carefully revised and updated to include the new 2003 International Building Code, ASCE 7-02 Minimum Design Loads for Buildings and Other Structures, the 2001 National Design Specification for Wood Construction, and the most recent Allowable Stress Design.
Defects and Deterioration in Buildings: A Practical Guide to the Science and Technology of Material Failure, Barry Richardson, Spon Press; 2d Ed (2001), ISBN-10: 041925210X, ISBN-13: 978-0419252108. Quoting: A professional reference designed to assist surveyors, engineers, architects and contractors in diagnosing existing problems and avoiding them in new buildings. Fully revised and updated, this edition, in new clearer format, covers developments in building defects, and problems such as sick building syndrome. Well liked for its mixture of theory and practice the new edition will complement Hinks and Cook's student textbook on defects at the practitioner level.
"Avoiding Foundation Failures," Robert Marshall, Journal of Light Construction, July, 1996 (Highly recommend this article-DF)
"A Foundation for Unstable Soils," Harris Hyman, P.E., Journal of Light Construction, May 1995
"Backfilling Basics," Buck Bartley, Journal of Light Construction, October 1994
"Inspecting Block Foundations," Donald V. Cohen, P.E., ASHI Reporter, December 1998. This article in turn cites the Fine Homebuilding article noted below.
"When Block Foundations go Bad," Fine Homebuilding, June/July 1998
Straw Bale Home Design, U.S. Department of Energy provides information on strawbale home construction - original source at http://www.energysavers.gov/your_home/designing_remodeling/index.cfm/mytopic=10350
More Straw Bale Building: A Complete Guide to Designing and Building with Straw (Mother Earth News Wiser Living Series), Chris Magwood, Peter Mack, New Society Publishers (February 1, 2005), ISBN-10: 0865715181 ISBN-13: 978-0865715189 - Quoting: Straw bale houses are easy to build, affordable, super energy efficient, environmentally friendly, attractive, and can be designed to match the builder’s personal space needs, esthetics and budget. Despite mushrooming interest in the technique, however, most straw bale books focus on “selling” the dream of straw bale building, but don’t adequately address the most critical issues faced by bale house builders. Moreover, since many developments in this field are recent, few books are completely up to date with the latest techniques. More Straw Bale Building is designed to fill this gap. A completely rewritten edition of the 20,000-copy best--selling original, it leads the potential builder through the entire process of building a bale structure, tackling all the practical issues: finding and choosing bales; developing sound building plans; roofing; electrical, plumbing, and heating systems; building code compliance; and special concerns for builders in northern climates.
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