The Contractors Exam: Rules I Didn’t Know About House Design

One of my favorite things about myself is my ability to be surprised– and I mean utterly astounded— at my own ignorance about things that I’m not sure why I expected I would know in the first place. Every hour of studying for this exam is a revelation.

Gasp! Houses have to be designed to have at least one habitable room with a minimum of 120 square feet? Why didn’t I know that?

Uh. Sister, did you see what happened the last time you tried to design a floor plan? Why exactly are you surprised?

These are the conversations I have with myself on a daily basis. Welcome to my life.

Hey, do you want to know some astounding rules about home design? No? Come back tomorrow and you can learn something about mice then. (Yeah. More mice.)

Things They Think You Can’t Mess Up

You don’t need a permit if:

  • You’re building an accessory structure (like a donkey shed) that only has one story and is less than 200 sq ft
  • You’re building a retaining wall less than 4 ft high
  • You’re putting in a sidewalk or driveway (less than 30″ above grade) that isn’t over top of a basement or bomb shelter or something
  • You’re putting on window awnings (mounted to exterior wall and projecting less than 54″)
  • You’re building playground equipment (Um… really? You’d think they’d regulate that.)
  • You’re doing finish work– cabinets, paint, counters, etc.

Also, you don’t need to get an engineer to stamp your plans unless your house is over 3500 sq feet (in which case, I know a book you should read), which is a damn shame, because I happen to live with a guy who has a stamp and he never lets me play with that thing.

Things They Think You Will Mess Up (And Therefore Require Inspection)

You need to get inspections for:

  • Footings (they go under your foundation walls… learn more here, it’s thrilling stuff)
  • Foundations (see link above for more info)
  • Base for pouring floor
  • Rough framing
  • Rough of the trades (electrical, HVAC, fireplace installation)
  • Final inspection

Let me tell you, I’ve lived through that process and it requires some in-depth information that I’ll feel more comfortable giving everyone after we’ve been given the big “pass” to move in. Reading all my info on the rules in these posts is a good start though.

Rules, Rules, Rules

It has to take a beating:

  • Rated to withstand 90 MPH winds (this is Michigan, remember)
  • Roof must hold 20-25 lbs of snow per square foot
  • Three story max

It can’t be a cave:

  • Natural light has to account for no less than 8% of the floor area
  • Natural venting no less than 4% of the floor area
  • Designed to maintain a winter temp of at least 60-degrees
  • It must have a toilet, lav, and bath/shower (now if only there were rules governing how often people had to use them… the shower specifically)

You have to be able to inhale without busting the walls out:

  • The house will be no less than 7′ across
  • You have to have on habitable room that is a minimum of 120 square feet
  • All other rooms have a minimum of 70 square feet (Kitchen is exempt, which explains some things)
  • Minimum ceiling height of 7′ (if the ceilings are sloped at least 50% has to be over 7′ and the area under 5′ can’t be counted toward the square footage of the house)
  • Shower area must have a minimum of 6′-8″ height and 30×30″ area

No, you can’t park the car in your bedroom

  • Door from garage/carport to house must be 1-3/8″ solid or honeycomb steel door (or 20 minutes fire rated)
  • Cannot open into the sleeping area
  • 1/2″ gypsum board must separate the garage from the living space, and if you have a room above the garage the ceilings have to be 5/8″ gypsum board

Emergency exits, for quick escape when your boyfriend realizes you just spent $900 on bathroom tile (hi, honey!)

  • Basement must have an egress window with a minimum of 5.7 sq ft (at least 20″ wide/ 24′ high, and the sill can’t be more than 44″ off the ground). Makes for a light and airy basement too.
  • The egress window well area has to be at least 9 square feet and a minimum of 36″ in either direction.
  • If you have sleeping areas in the basement, each one must have their own egress.
  • All hallways must be a minimum of 36″
  • One door from a habitable room (ie not a closet) has to be 36″ wide and 6′-8″ tall and go outside, not to the garage.
  • You can’t have more than an 8-1/4″ step going from outside to inside
  • Your threshold can’t be bigger than 1-1/2″
  • Your egress door can’t require a key to get out

For those of us who have a less-than-average command over our own feet

  • Handrails are required for 4 or more steps
  • You have to be able to slide your hand continuously without letting go
  • You must have 1-1/2″ space between the inside of the rail and the wall
  • A round handrail must be between 1-1/4″ and 2″ diameter
  • Not-round rails must have a perimeter of 4″ to 6-1/4″ and the corners have to be radiused to o.01″ (max width is 2-1/4″) — If you want to go larger than 6-1/4″ you have to put a groove in it
  • Rails must support a uniform load of 200 pounds per square foot
  • Any porch, deck, or balcony more than 30″ above grade has to have a railing — an intoxicated person will fall off of it at least once
  • Railing should be 36″ (34″ minimum for stairs)
  • No kid should be able to put their head through any part of the railing (so a 4″ sphere can’t pass through at any point)

I mean, are your eyeballs bleeding yet? I pulled a 4.0 in my MBA program, and yet I’m pretty sure that I am only going to pass the practical portion of this test on sheer dumb luck. Which is probably only fair because I’ve really only ever built half of  a house before, but also ironic because I care about building houses at least twice as much as I did about macro-economics.

Hey, come back tomorrow if you want to know some things about foundations and framing, or just to hear that story about how a rat one time ran across my front lawn carrying my bra.

11 Responses

  1. Dang. Do these apply just in your state or every state? I’m curious, are you planning to do any pro work with this license?

    Anyway, there’s nothing like practical application, so I can only imagine you know more than you think, and you’ll pass, no problem.

    1. That’s a good question Irina, they definitely apply in Michigan, and MI is a strict state. There are probably similar standards for every state, with varying degrees of tolerance — I know Ohio doesn’t require egress windows in the basement yet, for example.

      I don’t have any plans to do any pro work right now. I have a good day job and very little time for anything else, but I like to keep my options open.

      1. Much of the U.S. uses the International Building Code (similar to the Uniform Building Code), either as-is or with local amendments. Here in California there are additions for energy efficiency (Title 24) and earthquakes (which affects foundations and various parts of the framing).

        Here in Oakland, there are some additional amendments. A few of those are very local, like in the 1991 firestorm area. If the construction doesn’t have a fire resistant covering (e.g., stucco), then it’s required to have a layer of exterior drywall for increased resistance. I used wood siding on the addition to match the existing house, so the addition has a nice layer of drywall underneath the wood siding.

  2. Aww, the building code. You WILL actually have all those dimensions/clearances/etc. memorized at some point. And then, at parties you can randomly bust out some knowledge and impress all your friends!

    (Um…not that I know that first hand or anything.)

  3. Is it totally nerdy that I have the St. Paul building code book on my desktop? Because I do. We’ve pulled 12 permits on this charming abode of ours so far (yay permits!). So yes, we’re planning on getting our general contractor’s licenses within the next 12 months. : )

  4. Don’t knock rules. They are a good thing. When I had my family room renovated, I wouldn’t use a contractor unless he planned on getting all the permits necessary. I even did some research on my employer’s site, McGraw-Hill. I found out that gypsum board was fire resistant as well as mold and mildew resistant. It’s also easy to maintain and clean. The contractor I used said it was real easy to install also. Check out the McGraw-Hill website and see what information you will be interested in.

    1. Amy, were they considering an alternative to gypsum board? That’s what almost all drywall is these days. I’d be curious to know if your contractor was suggesting something else.

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