Planning outdoor seating: curb lines, seat counts and table sizes

The curb is two feet closer than you think. Measure before you shop.

Measure what you are allowed to use

Start with the boundary, not the furniture. On a sidewalk, your permit or your landlord decides where seating may sit and how wide the walkway must stay; on a roof, the building does. Get those lines in writing, then tape them on the ground. Note everything fixed inside them: a tree pit, a hydrant, a column, a door that swings out, a drain. Photograph the strip at lunch and again at dinner; a walkway always looks wider when nobody is on it.

Treat every figure below as a planning range for a sketch. Your local code's occupancy limit outranks every one of them. For the real site, your architect or designer checks building, fire and accessibility codes.

Square feet per seat

Use these ranges early, while the plan is still pencil:

• Fine dining, the roomiest: 18 to 20 square feet a guest
• Full-service rooms and terraces: 12 to 15
• Counter service or fast casual: 11 to 14
• Banquets and events, packed tight: 10 to 11
• Bars and lounges: roughly 10 to 12

Outdoors, lean toward the roomy end. Umbrella poles, heater footprints, planters and a stiff wind all eat space a dining room never loses. At 13 square feet a seat, a 2,400 square foot dining area holds about 185 guests; a strip of terrace a tenth that size holds about 18.

Tables by party size

Each guest wants roughly 24 inches of edge for the plate, and 18 is as tight as it gets. Then size the tops.

Two guests: 24 by 24 inches at the smallest, 24 by 30 for everyday, 30 by 30 when you can spare the room. Four guests: a compact 30 by 30, a comfortable 36 by 36, and against the rail a 30 by 48 rectangle. Rounds: 36 inches seats four if they are friendly, 42 to 48 fits four to six, and 60 handles eight.

A sidewalk strip loves two-tops. Push two together for a four and pull them apart for the next pair. Squares do that better than rounds.

Heights that pair

Dining: tabletop near 29 to 30 inches, and the chairs under it seated at 17 to 19, so knees get 10 to 12 inches under the top. Counter tops land near 34 to 36 inches; their stools sit 24 to 26. Bar tops reach roughly 40 to 42 inches, and the stools for them sit about 29 to 31.

Mixing heights on one patio is fine. Keep each table with its own seat height.

Room to move

Guests need 18 to 24 inches behind the chair to slide back. A service aisle wants about 36 inches. On a busy sidewalk that aisle is also how the server reaches the far table without stepping off the curb, so protect it.

Bar rails and high-tops with a view

Rooftop rails and street-facing ledges sell seats. From one stool's middle to the next: 24 to 30 inches. A 20-foot rail is 240 inches: ten stools at 24 inches, eight at 30. In wind, take the wider spacing and the heavier stool.

Accessible seating

For general guidance, here is what the 2010 ADA Standards for Accessible Design call for. Accessible dining tops: 28 to 34 inches off the floor, per section 902.3. Under the top, knee space runs at least 27 inches tall, 30 wide and 19 deep (section 306). Each accessible seat also needs open floor, 30 by 48 inches. The route to it: 36 inches wide at least, per section 403.5.1. Of all the dining seats, 5 percent or more sit at accessible surfaces (section 226.1). High-tops alone will not meet that, so keep some dining-height tables. Before you order, read the standard in its current form and the code your city enforces.

Bases and umbrellas

Spread a round base across two thirds of the top's diameter, minimum. A 36-inch round wants a spread of 24 inches or more. If guests will sit under umbrellas, choose tables with an umbrella hole and put a base under every pole, or set free-standing bases between tables. Count umbrellas and bases as their own lines.

Worked example: a 600 square foot rooftop

Say the roof gives you 600 square feet of usable deck. At 15 square feet a seat, which is full-service at its roomiest, that is 40 seats.

Split it by party. Six two-tops at 24 by 30 inches seat 12. Seven four-tops at 36 by 36 inches seat 28. That is 13 tables and 40 chairs.

Now the extras. Seven umbrellas over the four-tops means seven tables with an umbrella hole and seven bases. Add a 20-foot rail with eight bar stools and you can drop four of the two-tops, which keeps 40 seats with more room to walk. Check the aisles at 36 inches and the pull-out behind each chair, and make sure at least two seats sit at accessible tables.

Final list: 9 tables, 32 chairs, 8 stools, 7 umbrellas, 7 bases. Well over the 8-piece minimum, and every line ready for an outdoor plan.

From seat count to furniture count

The method is the same for any space. Divide the usable area by the square feet per seat. Split the seats by the party sizes you serve. Each party size gives a table count; chairs equal seats. Then add what the open air needs: umbrellas, bases, heaters, and room to store all of it at night.

Storage is the line people forget. Forty stacked chairs, nine tops and seven closed umbrellas need a corner somewhere, and the walk to that corner happens every night.

Put it in an outdoor plan

Build the list in an outdoor plan, one plan per space. Download the project sheet for the landlord or the permit file. Shop the pieces in patio tables and patio chairs, or book a specialist to check the layout with you.