Garden Dimensions
by Kate Easton, CPH
Allocating enough space in the garden for ‘hardscape’ is just as important as planting trees, shrubs, and groundcovers where they have enough room to grow and thrive. Although decks, patios and walkways don’t grow in the traditional sense, they may be expanded over time if not enough space is designated in the beginning. How do you know how big to make a parking area, patio or deck? A little up-front planning may prevent the most common design mistakes. Follow these standard dimensions for garden planning and design.
Driveways & Parking
The standard planning size for a vehicle in the landscape is 10 feet wide by 20 feet long and allows for parking space with doors open (compact to standard vehicles, SUV and trucks require more). A standard two-car garage is 22 feet by 22 feet (and so is the accompanying parking pad), barely enough room for side-by-side parked vehicles. If you have more than two vehicles or oversize ones, additional space will need to be allocated for parking and maneuvering them.
Add an extra two feet on either side of the parking pad to allow homeowners and visitors to exit vehicles without stepping on the garden plants. The addition can be in the same material as the parking pad, or contrasting colors, finishes or different materials. A concrete aggregate or tarmac surface can be bordered by pavers or bricks of a contrasting color. Better yet, use pervious concrete edged by a rain garden to increase the filtration rate of rain water back into the aquifer.
How does your drive way approach the garage or parking space? In suburban developments, the approach is typically straight in and out. In more rural areas, the ‘way in’ can be circuitous to accommodate wetlands, forests, or other natural topography. As a planning tool, make a to-scale map of your approach noting the location of your home relative to the property line. Create as many ‘car’ templates (10 feet by 20 feet) in that same scale and ‘drive’ them around that approach map mimicking the real experience. Go forward and back up into parking or garages will demonstrate how much garden space needs to allocated just for vehicles.
Here are some other standard dimensions for vehicles. The minimum width of a driveway is twelve feet if only standard or compact cars will use it. Additional width is needed for large trucks, RV’s or vehicles towing a trailer. The minimum curve for a driveway is a 17 foot radius (to the inside curve) – see diagram. Circular driveways will need a minimum of eighty feet in the direction parallel to the house and seventy-five feet in the perpendicular direction. The minimum radius for a circular drive is eighteen feet to the inside curve.
Walkways
Next, think about how to get from your now appropriately sized parking to the house. The primary access to the home is for visitors so it should be obvious and inviting to your guests. These walkways will last a long time if they are level and constructed of more permanent materials (concrete, pavers, brick, flagstone). Major walkways to the home are best if they are wide enough for two people walking side-by-side. A minimum width of five feet will accommodate two people, however six feet is better. A side benefit of wider walkways is lower garden maintenance since there are no plants to water, fertilize, weed or prune in that space. If you need to provide access for wheel chairs, a ramp that has a rise of 8.33% will meet the requirements of the Americans with Disabilities Act. (See http://www.usdoj.gov/crt/ada/stdspdf.htm for additional design standards for accessibility.)
Straight paths to the front door usually create a more formal feeling while a curving path is more informal. Choose the type of path that is consistent with the architecture of the house and the garden style. Many homes have a straight ‘L’ shaped entrance walk from the driveway to the front door. One way to widen a too narrow path is to edge it with pavers. When there is only a few inches available, planting a low growing ground cover tolerant of foot traffic such as Creeping Thyme (Thymus praecos arcticus) or blue Star Creeper (Pratia pedunculata) can give the illusion the path is wider than it is.
Secondary paths, such as those to the compost pile or potting shed can be narrower than the main entry to the home. If wheelbarrows or other garden equipment will be used on the path, a four foot width is the minimum. If the intent of the path is to take the visitor through the garden a leisurely pace, a path width of 18-24 inches can be used. The choice of path material depends on the path use, house architecture and the garden style. Flagstone, pavers, or flatter quarry rocks, crushed gravel, or shredded bark can be used on these secondary paths.
Decks and Patios
The size of a deck or patio is determined by how it will be used and by how many people. If this outdoor room is used for eating outside and entertaining a few friends, then sizing it like the interior dining room will provide enough space for a table and chairs and room to walk around it. Typically, an area that is 10 to 12 feet wide by the same will accommodate the standard picnic table with benches or 6 foot diameter round table and four chairs. If larger groups will be regular guests or room for a BBQ is needed, then the size of the outdoor dining room also needs to be larger. The general rule of thumb is the table dimensions plus 3’ 6" in all directions (for chairs and walking around). If the space will accommodate several tables an additional four feet between the chair backs will be needed to allow people to walk around comfortably.
Sometimes built in benches are added to the perimeter of a patio or deck to provide additional informal seating. When these are included, allow 18-24 inches of additional space between the edge facing the table and chair area.
When cooking will occur outside adjacent to the outdoor dining area, even more room is needed. An outdoor kitchen can range from 4-6 foot square or 8 – 10 feet or more. The determining factors are the size of the BBQ unit/cooker, presence of outdoor storage or counter space, and/or outdoor sink. An outdoor cooking area is best placed near to electrical and water outlets and close to a door to the interior kitchen. Moving ingredients and table settings from inside to outside will be quicker and more efficient the closer to the door they are placed.
New technology has created wood composite materials and high density plastics (e.g., Trex) that are suitable for decks of any size. The advantages of these new materials include few maintenance requirements and longer life. Expect to pay about 25% more for these than wood lumber. Flagstone in a range of colors is available and will complement most architectural styles. Concrete pavers and real brick can be set in a variety of patterns. Flagstone and brick have similar costs while concrete pavers are usually the least costly.
Arbors, Pergolas and Gazebos
Arbors are free standing structures that allow people to walk under them. They can be narrow such as over a gate or longer, over a path in the garden. In either case, the bottom edge of the cross piece is at least eight feet from the ground. Sometimes the height is higher to complement the architecture of the house or a steep slope or to be in better proportion to the house. Pergolas are arbor-like covers attached to a structure and are typically over a patio or a deck to provide light shade or support for vines. Like arbors, the height of a pergola will allow people to walk under it without ducking.
The width of an arbor is determined by the gate or path it is over (see path width discussion above). Most arbors and pergolas are constructed of lumber, however a few companies are now producing vinyl arbors paired with vinyl gates. Like wood composite deck materials, expect to pay more for this material in exchange for lower maintenance requirements. Vertical supports for arbors or pergolas range from 4 x 4 to 6 x 6 to 10 x 10 depending on the height and purpose. An arbor that will support a wisteria vine will need to have very substantial vertical supports while an arbor for climbing roses can use smaller lumber sizes.
Gazebos, free standing outdoor shelters, provide shade and protection from sun and rain with a solid roof. The size of the shelter is determined by the use and number of people that will use it concurrently. An intimate tea room could be an eight foot square with a couple of chairs. A space that will be used for large groups or outdoor dining will follow the rules for patios and decks. (See deck diagram elsewhere in this article.)
Several companies manufacture and sell gazebo kits for do-it-yourselfers. Materials for gazebos range from wood lumber to aluminum to steel. Pricing for kits is directly related to quality and longevity. Custom designed and built arbors, pergolas and gazebos will cost more than most kits and have the most choice in materials and design.
Fences and Privacy Screens
Sometimes the only way to mask an undesirable view is to build a fence or screen. A six foot high fence provides privacy for both seated and standing uses in the garden. If a barrier is needed to define a space or direct foot traffic, a four foot high fence can be used. When houses are close together and windows align between houses, a privacy screen that blocks views into the other house can be used. The height and size of such a screen will be determined by the size of the window and the distance between houses. For those communities that have covenants that govern fence height, a possible solution is to use free standing screens place a strategic points that can provide some privacy. Screens can be a dense diagonal lattice or a more open rectilinear design. Planting vines to climb the screen will provide the added benefit of creating the illusion of depth and connect the structure to the living garden.
Sometimes it will help to visualize the size of a proposed garden element by laying a garden hose or spraying paint (special biodegradable, ground-marking type) to outline the planned dimensions. Walk around in that space or place tables and chairs in that space to become comfortable with the size. When built elements are the best solution to the garden problem, these garden dimensions standards will help to ensure that garden spaces are people sized and in proportions that complement the garden.
|
