ADDITION PLANNING DO'S AND DONT'S Part Two of Two Parts

A hand-drawn "as-built" floor plan is fine, as long as
your measurements are accurate. Or...

Last time, we looked at all the un-sexy preliminary steps that are necessary enroute to designing a home addition. Not one of them, you’ll recall, involved any drawing. Rather, there was a lot of preliminary wish-list making (creating the program), fact-gathering (the survey), and ensuring that what you want to build conforms to local zoning codes (your conference with the local planner).

Now, armed with the confidence that your scheme won’t get blown out of the water by unanticipated restrictions, you can move on the the next step:

...if you want to get fancy, you can use a
consumer-level CAD application such as Sketchup
to show your existing house.

• Measure your existing house and draw the floor plan to scale, whether on paper or using a consumer-level drafting program--there are several available at a reasonable price, and others that are free. Take your time and measure carefully, as the success or failure of some designs can come down to mere half-inches.

• Using the existing floor plan you’ve drawn--and following the planner’s guidelines for the area that’s buildable--determine how the addition will communicate with the existing house. Don’t settle for a half-baked solution such as passing through a bedroom--provide a proper hallway even if it means having to recoup the lost space someplace else. At this stage, you’ll be wasting your time if you’re making neat, careful drawings. Just hang loose, drawing rough bubble-shaped rooms on inexpensive tracing paper. Don’t get stuck on one idea right at the outset--try out as many different solutions as you can.

But DON'T waste your time trying to do preliminary
design on the computer. Rough bubble diagrams
drawn with pencil and paper are much faster and
 less of a creative constraint.

• Still using rough bubble diagrams, determine the ideal solar orientation for each of the new spaces. Typically, major living areas such as family rooms should face south where they’ll get maximum sun. Kitchens and breakfast rooms ideally face east to southeast, while bedrooms are faced to suit the sleeper’s preference for morning sunshine or the absence of it. The least important rooms, such as the garage, secondary baths, laundry rooms, and the like, are given the least desirable northern orientation. Don’t expect perfection, but remember that a decent attempt is better than nothing. 

•  Only now should you begin sketching out some preliminary drawings using straight lines. Whether you’re working on paper or computer, pay careful attention to crucial minimum dimensions such as the width of hallways (rock bottom minimum,  three feet wide), stairs (ditto), clothes closet depths (two feet minimum), and kitchen aisles widths (no less than four feet). You’ll be sorely tempted to cheat on these minimums in order to wedge in just a few more of the features you crave. Don’t--you’ll end up with a nonfunctional and obviously amateur plan. Always err on the generous side.

The irony: If your addition design is really successful,
no one will ever notice it.

• When you think you’ve included everything you want--or you’ve tossed out the spaces or features that simply don’t fit--you can finally begin the “hard-line” drawings of your floor plan using a computer or drafting tools. Note how many steps were necessary before even getting to the portion of the work that most people consider “architecture”. 

It’s the willingness to lay this often tedious groundwork that distinguishes a thoughtful, well-designed end product from standard amateur-hour bungling. Whether you choose to tell admirers how much work your project entailed—or whether, Like Frank Lloyd Wright, you claim you shook it out of your sleeve—is up to you.