Crawl Space Access
Codes, standards, methods when crawl space access is limited or none
POST a QUESTION or READ FAQs about entering crawl spaces and similar tight building areas: what if there is no access or if access is unsafe?
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Access to crawl building crawl spaces:
This article describes the accessibility requirements & codes the required size & location for crawl area openings in buildings, the standards & procedures for entering crawl spaces, and we explain how can we inspect a crawl area and building conditions when safe, ready access are not already provided.
We also provide a MASTER INDEX to this topic, or you can try the page top or bottom SEARCH BOX as a quick way to find information you need.
How to Get Into a Crawl Space That Has No Ready Access
Watch out: Before entering a crawl space to inspect its condition or to clean up the crawl space or make repairs in the crawl area.
At CRAWL SPACE SAFETY ADVICE we list a variety of reasons not to enter a crawl space. And even if you think the crawl space is not obviously dangerous, limited space or other risks often mean that you should not work alone and not enter the crawl area without assistance and aid standing by.
[Click to enlarge any image]
Ultimately home inspection associations and standards, even if they describe minimum crawl space opening sizes, also must allow that an inspector can and should refuse to enter a crawl area that s/he considers unsafe for any reason.
The decision not to enter the crawl area and the reasons should of course be documented and appropriate follow-up steps should be taken as well.
While some crawl areas under buildings are safe, roomy, dry, and easy to move around in, other crawl spaces can be really ugly or hard or even impossible to enter without making an access opening and wearing protective gear.
Building codes require that crawl spaces be made accessible.The 2012 IRC describes the minimum crawl space accessibility requirements as follows:
Access shall be provided to all under-floor spaces. Access openings through the floor shall be a minimum of 18 inches by 24 inches (457 mm by 610 mm).
Openings through a perimeter wall shall be not less than 16 inches by 24 inches (407 mm by 610 mm). When any portion of the through-wall access is below grade, an areaway not less than 16 inches by 24 inches (407 mm by 610 mm) shall be provided.
The bottom of the areaway shall be below the threshold of the access opening. Through wall access openings shall not be located under a door to the residence. 
Photo at above left is of the author, Daniel Friedman, peering into an inaccessible crawl space while suffering from a broken leg. Photo courtesy of Arlene Puentes.
Entering a hard-to-access crawl space: if necessary, make an access opening and while there fix everything you can
At a home where there was no crawl space entry whatsoever, and where inspection was necessary, we pulled back carpeting, found the floor joists by noticing the nail pattern in the subfloor, cut a removable subfloor panel at the center of joists (so it would be easy to replace), and made our own crawl space entry door.
In a different building investigation, the crawl space shown in our photos (below) turned out to be clean and dry. But access to the crawl space very tight and like the home in our photo at left, the second building originally it had no entry opening whatsoever.
We needed to get in to the crawl area to inspect (and repair) floor framing support (shown in our photo at below left) as well as to understand house conditions.
We took advantage of a bathroom renovation project to make an opening through the flooring above.
An alternative crawl space entry could have been made from outside with a bit of digging and cutting an opening through the foundation wall. We left a removable panel to enter the crawl area. If an outside entry had been made through the foundation we'd have made sure that the entry itself didn't become a water entry pathway by protecting it from surface and roof water.
Once going to the trouble of making an access to get into the crawl space we don't waste the effort. We reinforced existing floor supports that had not been checked since the home was built in 1920 and we added a few improved posts ourselves (above left).
We then added insulation (above right) under the floors and even though this crawl area was dry, before leaving we put down 6-mil poly on the dirt, making crawling (slithering in this case) easier for the next person who would have to work in the area.
What to do if a crawl space is literally inaccessible
If a crawl area is literally inaccessible because there are only a few inches between the floor framing and the crawl space surface, no one can enter it.
If there are crawl space vents it may be possible to remove the vent screen to permit a partial view into the crawl space, but it's not easy.
Crawl space vent covers were typically installed and secured from inside the foundation wall during construction. I'd consider destroying the vent cover if necessary, replacing it from outside later.
For such areas we have made inspection openings through the floor above. If on inspection we find conditions that absolutely need repair such as toxic mold, sewage, rot, insect damage, then the floor will have to be removed to permit repairs.
What if there are no crawl space entry openings and no holes to even peek into the area?
Our pro-bono inspection of a church crawl space (you couldn't pay anyone enough to do this) began at the floor opening shown at above left. Our second photograph (above right) shows how little space there was between the floor joists and the soil below. This crawl space is impossible to enter.
Inaccessible Crawl Spaces: using secondary clues about building condition
When a crawl area is impossible to enter and when view is quite limited we have to rely on secondary clues of crawl space condition. Examples of such clues that are collected from above include:
Outside: drip lines below roof eaves indicating a history of gutter overflow and water spillage by the foundation - high risk of water entry, rot, insect damage.
Indoors: sagging floors, crunchy flooring (termite damage), odors, evidence of insects coming up through the floor, evidence of recent structural repairs, evidence of insect pest treatment;
When in the judgment of an experienced building diagnostician the accumulation of clues suggesting hidden trouble is sufficient, it becomes cost justified and appropriate to begin further invasive inspection by making test openings and where those inspections confirm trouble, more flooring will need to be removed.
Definitions of Accessible or Inaccessible Crawl Spaces & Confined Spaces: OSHA & ANSI Standards
Watch out: ASHI and other home & building inspection associations have argued for decades about the definition of "accessible" or "safely accessible" areas in buildings. A bottom line that is or should be shared by all such organizations is that in actual practice, in the field, the final decision on whether or not a building area can be safely entered for inspection or other work must rest with the on-site professional.
Even where there is more than adequate physical room to enter a building area there may be reasons that the inspector feels the area is unsafe to enter or unsafe to enter without additional safety equipment, precautions, even additional support personnel.
OSHA regulations addressing confined spaces in OSHA 29 CFR 1910.146 and 29 CFR 1926.21 (osha.gov), and in American National Standards Institute ANSI Z117.1-1989 (webstore.ansi.org/) , Safety Requirements for Confined Spaces - from which we quote, (also referring to IICRC-S520 draft standard for mold remediation projects)
Definitions used by OSHA and ANSI for a “confined” or “enclosed space” list the following attributes of the space: a confined space
is configured so that an employee can enter it;
has limited means of ingress or egress; and
is not designed for continuous occupancy.
If it is determined that the workplace is a confined space, then the confined space entry program (for OSHA-regulated workplaces) must include:
determining if the space meets the definition of a Permit-Required Confined Space;
identifying the confined spaces and hazards in the workplace;
monitoring of atmospheric conditions in the space;
instructing workers on the proper use of the safety equipment;
defining the duties of the confined space entry team; and
developing training requirements for employees who enter the confined space.
Permit-required confined space (permitted space, again for OSHA-regulated projects) means a confined space that has one or more of the following characteristics:
it contains or has a potential to contain a hazardous atmosphere;
it contains a material that has the potential for engulfing an entrant;
it has an internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls or by a floor that slopes downward and tapers to a smaller cross-section; or
it contains any other recognized serious safety or health hazard.
If it is determined that the confined space is a Permit Required Confined Space, then the confined space shall have a posted permit and remediators shall comply with OSHA entry requirements.
Continue reading at CRAWL SPACE SAFETY ADVICE or select a topic from closely-related articles below, or see our complete INDEX to RELATED ARTICLES below.
 International Residential Code, IRC Section R408, Under Floor Space, http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_4_sec008.htm, retrieved 3/2/2013
See IRC Section M1305.1.4 [PDF] for access requirements where mechanical equipment is located under floors.
 International Residential Code, IRC Section R406, Foundation Waterproofing and Dampproofing, http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_4_sec006.htm, retrieved 3/2/2013
 Electrical shock injury statistics: www.healthatoz.com - September 2008;
 US Centers for Disease Control, CDC: www.cdc.gov/ncidod/diseases/hanta/hps/ describes the risks associated with hantavirus.
 Arlene Puentes, an ASHI member and a licensed home inspector in Kingston, NY, and has served on ASHI national committees (Bylaws, Standards), as well as HVASHI Chapter President. Ms. Puentes can be contacted at email@example.com
Asbestos: How to find and recognize asbestos in Buildings - visual inspection methods, list of common asbestos-containing materials
Fiberglass: Indoor Air Quality Investigations: Health Concerns About Airborne Fiberglass: Fiberglass in Indoor Air from HVAC ducts, and Building Insulation
Lighting, proper use of: proper aiming of a good flashlight can disclose hard to see but toxic light or white mold colonies on walls.
Roger Hankey is principal of Hankey and Brown home inspectors, Eden Prairie, MN. Mr. Hankey is a past chairman of the ASHI Standards Committee. Mr. Hankey has served in other ASHI professional and leadership roles. Contact Roger Hankey at: 952 829-0044 - firstname.lastname@example.org. Mr. Hankey is a frequent contributor to InspectAPedia.com.
Arlene Puentes, an ASHI member and a licensed home inspector in Kingston, NY, and has served on ASHI national committees as well as HVASHI Chapter President. Ms. Puentes can be contacted at email@example.com
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