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Crawl Space Access

user-18774 | Posted in Construction Techniques on December 9, 2003 04:41am

I’m a fairly new residential general contractor, and due to the warmer climate and minimal frost levels where I build all of my first five homes were build on a concrete slab on grade (SOG). But the next two homes I have to start are utilizing a crawl space foundation. I’ve read several threads here and several articles within FHB regarding crawl spaces, but haven’t found anything about access panels/doors to the crawl space itself. So I was wondering if anybody could help with a few questions:

 

1.      Are access panels typically installed within the interior of the home accessing through the floor? Or in an exterior concrete foundation? I’m assuming and hoping the prior.

2.      If you place them within the house where are you typically locating it? Closet, pantry, laundry?

3.      Do floor finishes effect the placement? Or in other words is it easier to install within a wood floor rather than a tile floor? Carpet? Can you make it hide with any of these materials?

4.      Are there manufactured models that work well?

5.      Are there details for the construction of an access panel? Do you remember the article “AIRTIGHT ATTIC ACCESS†by Mike Guertin in the June/July issue? I’m looking for something similar to this but for crawlspaces.

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  1. jimblodgett | Dec 09, 2003 05:07am | #1

    Here in Western Washington, 90% of new homes are built with crawl spaces, usually 24" stemwall on an 8" footing.

    The reason I mention were we are is because we haven't (apparently aren't going to) adopted that IRBC that many other states have adopted, we are still using the '97 U.B.C.  And that spells out pretty specifically what is required for crawlspace access - I'm almost positive it's 24" wide by 18" tall clear opening.

    The other thing to consider is that we are also required to vent crawl spaces (you guys can quit rolling your eyes back in your heads now) so there's no point trying to provide an air tight door on the access hole - I usually build a simple wooden frame, staple hardware cloth to it, and screw it to pressure treated 2x6 that line the opening - just to keep the opossums from taking up residence under there.

    We happen to own a duplex that was built in the early 70s that the crawl space access is in the floor of a bedroom closet - what a pain in the arse that is.  Even if it were legal (which it might be) to still do that, there's no way I'd do that after my experiences with that danged duplex - redo a little plumbing?  Gotta drag tools and old pipe in through the bedroom.  Want to restaple some insulation or rewrap the exposed pipes?  Go through the bedroom (and you know danged well how clean you are after crawling around under there for half a day).

    Don't screw around, Crash, provide adequate access, from outside the building.  Even if code doesn't require it.  At some point, the homeowner will be grateful you did, even if they don't realize it. 

    1. FrankB89 | Dec 09, 2003 06:09am | #2

      I totally agree with Jimbo.  Through-the-floor crawlspaces, while convenient for the builder (I guess) are really a pain for the HO.  Typically, they're in a closet and utilizing them for maintenance can be an ordeal, especially if the closet is well used and requires a bunch of cleaning out before the trapdoor can be opened and most of the time, the trap door itself, usually poorly made, is a struggle to get open.

      It's really simple to block out for a crawlspace opening in the stemwall when doing the foundation, much as Jim describes.

      And I prefer to make them a little larger than code when possible so access and egress is a little easier on aging bones and joints.

      If grade is a problem, a window well unit or a set of concrete steps within a masonry well will long be appreciated.

       

      1. xMikeSmith | Dec 09, 2003 07:51am | #3

        crash... wether you vent the crawl or not... provide outside access..

         i usually pour PT bucks in the wall  and then build a nice door to fit..

        everyone that goes in will either thank you , or curse you... including yourself...

         inside access is too costly in terms of floor space and traffic patterns.. not to mention homeowners don't  want the things that eventually have to be hauled in and out of crawl spaces to be dragged thru their living room

        but hey, whadda  i no ?Mike Smith   Rhode Island : Design / Build / Repair / Restore

  2. User avater
    CapnMac | Dec 09, 2003 10:35am | #4

    Through the foundation wall, without a question (we want to keep the insulation envelope as unperforated as possible).

    Please, please, slope the crawlspace to someplace other than the access, too 9if possible).  Not much fun to find a hollowed-out wanna-be sump right at the point of access.

    Resist putting the access in the middle of the deck which covers up the "unslightly" access (unless you put a trap in the deck--which is not much better).

    Make sure that the floor system or rim joist won't have a problem spanning an 18" or 24" opeingin, too (makes for unpleasant conversations with the inspector).  Any more depth you can get under the floor (24" is typical for many codes) will be appreciated by anyone going under the house.  Foundation plans ought to make most of this at least a little more clear.

    Occupational hazard of my occupation not being around (sorry Bubba)
  3. dIrishInMe | Dec 09, 2003 06:11pm | #5

    Agree with most all of the above: Exterior access.  The requirement is usually 18"x24 or large enough to allow swapping out what ever mechanical equipment will be down there - ya gonna put the water heater down there?  What about an air handler?  So, in practice, the opening is often much larger.  Also, think about what you want your finished opening size to be (after framing the jamb).  Put your crawl entry at the point on the house where the foundation will be highest above grade (assuming some slope to the lot) but not on the front of the house (obviously).  This way, you will be able to make your access door as large as possible.  On my personal house, the lot is sloped to where there is about 6'6" headroom in the crawlspace at the back corner of the house.  I installed a cut down 3-0 steel prehung exterior door as my access.    If you are doing an engineered floor system (I-joist) put an LVL or similar inside the rim board of the floor system above the crawl opening.  If it's gonna be a 2x10 floor system build in a header by doubling the rim joist above the crawl opening.  Or, have your masons put a lintel above the crawl entry.

    Matt
  4. JohnSprung | Dec 09, 2003 10:28pm | #6

    Not sure if it's code or just common practice, but here in LA crawlspace access is always from the exterior thru the stemwall and/or cripple wall.  In addition to the dirt and inconvenience issues, a trap door into the house from the crawl is yet another way for a burglar to get in. 

    -- J.S.

  5. JohnSr | Dec 10, 2003 03:15am | #7

    2000 IRC One and Two family dwelling code requires a minimum access of 18 x 24 unless HVAC, water heater, etc. is located in the crawl in which case the opening must be large enough to service the mechanical equipment.

    The "Journal of Light Construction" had an excellent article on sealed crawl spaces about three months ago.  Go to http://www.jlconline.com - you can search for the article there.  There are some specific code requirements that must be met to build a sealed crawl space, may not be allowed in your area.  You have to esentially make it a conditioned space and install a minimum 50 CFM blower to supply conditioned air to the crawl space.

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