DESIGN PROPORTIONS IN THE OUT-OF-DOORS

You simply can't make outdoor steps too shallow.
However, remember to make the steps deeper as you make
the rise shallower, using the formula Rise± Run=17.5".

Designing landscape structures—decks, gazebos, planters and the like—is a lot different than designing buildings. The scale of the outdoors is vast, and dimensions that might be perfectly appropriate inside a house can result in a major case of the wimpies when used outdoors.  Here are a few examples:

If there's nothing to stop you from making the deck steps
full width—do it. Steps make a lovely place to sit and relax.

•  Stairs are the most frequently screwed-up detail of outdoor designs. While the Uniform Building Code allows interior stairs as steep as 8” rise by 9” run, such dimensions are aesthetically disastrous outdoors. For decks, patios, and landscape stairs, you shouldn’t exceed a maximum 6” riser with an 11” run.  Preferably, stairs should be even shallower. A useful formula for stairs, whether indoors or out, is:  Rise+Run=17.5”. It’ll help you adjust the rise and run to the slope the slope of the landscape while maintaining comfortable stair proportions.

Another common mistake in designing outdoor steps is to make them the same width as the typical indoor stair, which is typically about three feet. Alas, this yields what my mother would call a hühner leiter: a chicken ladder. Such steps are much too narrow in the context of the landscape. Deck steps, for example, should be a minimum of six feet wide, and even wider if possible. In fact, if there’s nothing to stop you, make your steps the full width of the deck. The extra cost is trivial, and they’ll make a fine spot for sitting on warm evenings.

Fussy gazebos, such as this prefab one
made by a well-known company, won't hold up well
in the weather, and look wimpy and inconsequential outdoors.

•  Because the outdoors is so—well, big—structures and decks can look insignificant unless their scale is increased somewhat. For example, while an indoor breakfast room measuring 9’ by 9’ feet might be acceptable, an outdoor gazebo built to these dimensions will look positively dinky. It’s best to increase the scale of such structures
(including their ceiling heights) by about 20 percent or so over their indoor counterparts. Likewise, decks meant to accommodate outdoor furniture should be no less than twelve feet deep—otherwise, occupants will always feel as though they’re about to fall off the deck edge.

This gazebo is simpler, heavier, and will only
get better looking  as the years pass.

• Even railings need to be beefier in the scale of the outdoors. For instance, the usual 1/2” square wrought iron balusters commonly used indoors will look like gossamer when they’re installed outside. If you have your heart set on a wrought iron rail, try using 3/4” square balusters with commensurately heavy posts and top and bottom rails. Or, cap the top rail with a chunky piece of lumber such as a 3x4 (but use a good quality vertical-grain lumber to avoid splinters).

This combined steel (a.k.a. "wrought iron") and wood rail
avoids the gossamer look of most all-steel railing designs.

If you’re planning to use a wood rail, avoid finicky construction details that employ spindly stock such as 1x2s or thin lattice material. Aside from looking frail, such small-scale materials are highly susceptible to the ravages of weather and partying teenagers. They’ll look great the day they’re installed, and then fall to pieces not long after. In outdoor designs, the rule is simple: the bigger, the better. Use substantial lumber sizes, and try to avoid nominal 2” lumber altogether.

Certain kinds of joinery are also bad news outdoors. For all their vaunted beauty, miter joints seldom hold up well over time. Even the most carefully-constructed miters will eventually open up and look shabby within a few years (often, in even one season.) Simple, square-cut butt joints—especially ones with a healthy overlap that conceals shrinkage—are much more resistant to the effects of weathering.