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How to Make a Hole in the Floor

A

Amish Electrici

Bronze Member
Joined
Apr 24, 2012
Messages
39
My house is a 2x4 frame, ranch style set over a crawl space. I'd like to add an access to the crawl space from within the house.

Any such hatch would be sure to require me to cut at least one floor joist. What are the 'rules' for doing this? How should the opening be framed?

I welcome any suggestions or links.

Thank you.
 
I'd let the plumber do it.

They don't seem to have any difficulty in cutting up or through a joist.
 
it's like framing out an opening for skylight only in your floor. easy. double the joists you use for the sides of the opening, double the header pieces on both sides. install joist hangers. make sure your floor doesnt dip while doing it
 
Amish Electrici said:
My house is a 2x4 frame, ranch style set over a crawl space. I'd like to add an access to the crawl space from within the house.Any such hatch would be sure to require me to cut at least one floor joist. What are the 'rules' for doing this? How should the opening be framed?

I welcome any suggestions or links.

Thank you.
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Are you sure that the floor joists are on 16" centers? Even if they are, typically one joist can be headed off without doubling the joists on either side. Consider the location and cut the joist 1 1/2" beyond the edge of the hole in the subfloor on each end. Single header joists will be fine and as long as you're sticking with single members no hangers are necessary.

Section R502.10 Framing of openings.

Openings in floor framing shall be framed with a header and trimmer joists.When the header joist span does not exceed 4 feet, the header joist may be a single member the same size of the floor joist. Single trimmer joists may be used to carry a single header joist that is located within 3 feet of the trimmer joist bearing. When the header joist span exceeds 4 feet, the trimmer joist and the header joist shall be doubled and of sufficient cross section to support the floor joists framing into the header. Approved hangers shall be used for the header joist to trimmer joist connections when the header joist span exceeds 6 feet. Tail joists over 12 feet long shall be supported at the header by framing anchors or in ledger strips not less that 2 inches by 2 inches.

Bill
 
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It is true, 18" X 24" is the smallest opening that the code permits. I would sugest that if you can, make it larger. 18" X 24" is pretty tight, particularly if you have a tight crawl space. Yes , I realize it would be tigher for some of us than others. But even for a relatively young man in good shape, 18" X 24" is none too large.

Without knowing more about the size of floor members, span of members, spacing of members and even grade and species of the materials used, it is difficult to know whther or not the side joist that would be holding the header members need to be doubled or not.
 
Access from the inside is a good idea if you have a conditioned (unvented) crawl space. Otherwise need to consider the details for maintaining the insulation barrier and air seal.

2308.8.3 Framing around openings. Trimmer and header joists shall be doubled, or of lumber of equivalent cross section, where the span of the header exceeds 4 feet. The ends of header joists more than 6 feet long shall be supported by framing anchors or joist hangers unless bearing on a beam, partition or wall. Tail joists over 12 feet long shall be supported at the header by framing anchors or on ledger strips not less than 2 inches by 2 inches.

FloorOpening.jpg


http://www.ce.udel.edu/courses/CIEG407/Class_17/Wood%20Chapter%2023%20-%20IBC.pdf

Francis

 
If there is already a qualifying access from the exterior, does a new interior access have to meet code? Years ago I cut through the plywood directly over the floor joists and 24", so ended up with only a 16" x 24" opening, kinda tight, but if a storm was approaching, we'd be able to use it in a pinch, literally, but wouldn't have to run out in the rain to access the other port.
 
See Francis' post #8, pull a permit, pray and hope you don't need stairs or need a RDP and call for inspection?

pc1
 
Thanks for the replies- especially Francis, with the artwork!

I'm all in favor of large openings. With that in mind, I'll make it as wide as I can, while cutting but one joist. In the end, I'll probably have a clear opening about 30" square. I might have to double the framing around the opening - not quite the same as doubling the joists - simply for attaching the hardware and trim work. Working in full-length pieces to double the joists is something I'd just as soon avoid, as that is much more of a challenge in an existing building.

I will also confess to a bias toward using joist hangers.

Shoring while working will certainly make the job easier; no sense installing a dip in the floor when I attach the headers!

FWIW, the house does have a code-compliant opening in the foundation wall. This opening is in addition to it, for the purpose of gaining easier access to the plumbing
 
SECTION 105 PERMITS

105.1 Required. Any owner or authorized agent who intends to construct, enlarge, alter, repair, move, demolish, or change the occupancy of a building or structure, or to erect, install, enlarge, alter, repair, remove, convert or replace any electrical, gas, mechanical or plumbing system, the installation of which is regulated by this code, or to cause any such work to be done, shall first make application to the building official and obtain the required permit.

SECTION R105 PERMITS

R105.1 Required. Any owner or authorized agent who intends to construct, enlarge, alter, repair, move, demolish or change the occupancy of a building or structure, or to erect, install, enlarge, alter, repair, remove, convert or replace any electrical, gas, mechanical or plumbing system, the installation of which is regulated by this code, or to cause any such work to be done, shall first make application to the building official and obtain the required permit.

No where in 105.2 or R105.2 Work exempt from permit does it list cutting away of structural members as being exempt.:confused:
 
rogerpa said:
SECTION 105 PERMITS 105.1 Required. Any owner or authorized agent who intends to construct, enlarge, alter, repair, move, demolish, or change the occupancy of a building or structure, or to erect, install, enlarge, alter, repair, remove, convert or replace any electrical, gas, mechanical or plumbing system, the installation of which is regulated by this code, or to cause any such work to be done, shall first make application to the building official and obtain the required permit.

SECTION R105 PERMITS

R105.1 Required. Any owner or authorized agent who intends to construct, enlarge, alter, repair, move, demolish or change the occupancy of a building or structure, or to erect, install, enlarge, alter, repair, remove, convert or replace any electrical, gas, mechanical or plumbing system, the installation of which is regulated by this code, or to cause any such work to be done, shall first make application to the building official and obtain the required permit.

No where in 105.2 or R105.2 Work exempt from permit does it list cutting away of structural members as being exempt.:confused:
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Well if you think that you must....then I guess you must.
 
see your building official and tell him what you're gonna do and see what he says .... he'll probably have a shocked look on his face that someone actually asked
 
For all those expressing concern over a permit .... thanks, but you're preaching to the choir.

My practice is to do my research first ... over time I have developed an exceptionally good reputation with the local inspectors, and I wish to keep it that way. Proper planning preventing poor performance, etc.

In some instances - another thread I have going in the plumbing section is an example -my desires present the inspector with issues he has not ever faced before. It's nice to be able to call up a thread, and show him the take from others in the biz, whether tradesman or inspector.

Though, my move here to the hinterlands has brought another matter to my attention: would you believe there are actually parts of the USA where even the local government believes what a man does with his house is none of their business - and wouldn't dream of stepping in? Here, if it does not involve a utility company or change the footprint of the house, they're really not interested.

Indeed, I see far more of the local building inspector at the local animal shelter; we're both members. This, btw, made for an interesting confrontation at my doorway when an imposter attempted to gain access to my place, claiming to be from the building department- but that's another story.
 
Most show indentification R104.5 and arrive in a white codes car, riding the short bus does not count. ;)

(color of the codes car is optional)

pc1
 
Amish Electrician,

How do you plan to address the insulation & air sealing of this new

interior crawl space access (RE: Francis' post above)?
 
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The simple hatch hardware ought to provide the air sealing. As for insulation ... from a code view, I don't think any is required. There's none under any part of the house. For that matter, even in more severe climates I don't recall anything special being done with the hatch.

Seriously though .... you raise a good point, and I will have to see what sort of hatch I wind up with. Simply using an aluminum treadplate with a gasket on the perimeter and a piece of rigid foam attached ought to work wonders. Another approach is to have a lightweight lower panel, supporting the insulation (similar to what is done with some attic hatches. It's also possible that the hatch will become a full joist-depth box, just to transfer floor loads to the framing. After all, the hatch might be stepped on at some point.

Indeed, since this hatch will be in an open part of the room, the handles and other hardware are likely to pose more of a challenge. (Location will be pretty much in the middle of a laundry / utility / "mud" room).
 
Well, Log Cabin, your question brings up a few points that ought to be addressed - though they are a bit off-topic. Bear in mind as you read that I am addressing several different sorts of folks with my various answers.

First off, it's my house, and it's really beyond the authority of ANY government functionary to ask me to justify myself in this free country of citizens - rather than subjects. I want it. That is enough reason. Scoff if you will, but it's not your call to make.

There's a lot of things in the crawl space, a lot of reasons one goes there .... the plumbing being but one. That said, plumbing IS designed with parts that are intended to fail, or need maintenance, over time. Simple traps can clog, as one example. Likewise, a man might wish to add a water filtering arrangement, considering the numerous failures these past few years of governmental supplies to meet standards, outright governmental lying about purity (re: the fluctuating arsenic standard), and even the deliberate government decision to add a minor amount of sewage to the fresh water supply (Los Angeles). Filters need regular maintenance.

FWIW, this house dates from 1957. It's time to replace the plumbing - there is evidence of some sewer problems - and I had a gas line rot out this past winter. That crawl spaces get used as little as they do is a real testament to the various tradesmen.

Myself? I've made a career of using the crawl space to run wires. In this house I intend to run the AC line sets there, so as to expose as little as possible to the copper thieves. I have an interest in easier access.

Just because there exists an opening already, that opening might not be well situated. Besides, who wants to walk through the pouring rain and belly-crawl through melting slush to enter the crawl, when one can enter from the comfort of the mechanical room?

I was in one house with a very accessible crawl space. It actually was lined with an old carpet; the toddlers loved playing in their 'secret room.'

Finally .... now, this might not be easy for everyone to relate to ... but, every now and then, some yokel nearby fires his gun. Now, I can't speak for you guys, but I'd like there to be another exit, one that didn't advertise its' presence to every ne'er-do-well. Heck, the crawl might even qualify as a tornado shelter .... probably better than hiding in the bathtub.

Maybe we need an ad campaign: Crawl Spaces: Not just for spiders anymore! :D
 
Why be concern about energy code when the house probably doesn't have much for insulation to begin with let alone draft sealing.

Having dealt with several cellar floor doors they are quite heavy to lift as are some of those bulk head doors. You may already have a design or product in mind and if I may suggest two smaller doors that swing on a fulcrum at approximately one-third from the end and when fully opened will rest against the top of the floor. Install a set of heavy duty hydraulic pistons; like those at the rear lift gates on mini-vans to assist with the weight of the doors when lifting. The wood at these stress areas will have to be re-enforced with metal plates.

FWIW; some crawl spaces could use two accesses to shorten the travel distance.

Francis
 
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Amish Electrici said:
I was in one house with a very accessible crawl space. It actually was lined with an old carpet; the toddlers loved playing in their 'secret room.'
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That's just

goofy_by_zdrer456-d45ukk1.jpg
 
First off, it's my house, and it's really beyond the authority of ANY government functionary to ask me to justify myself in this free country of citizens - rather than subjects. I want it. That is enough reason. Scoff if you will, but it's not your call to make.
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Agree 100%. I grew up in an area where all construction was slab on grade and plumbing drain lines are inaccessible and never seemed to be a problem. Just wanted to know your thoughts

Personally I would never put anything that needed service or maitenance in a crawl space but existing buildings are what the majority have to work with and your options are limited
 
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