Making a Base Plan
by Judith Irven

Here is the way to measure and draw up a base plan of your garden. This plan, which shows just the things that currently exist, is the foundation of any new design work you may undertake.

Which scale is best for landscape plans?
For most landscape drawings a scale of 1/8” = 1 foot is ideal. This means that an object that is 1 foot on the ground will be represented as 1/8” inch on your drawing. With this scale you can show important things like paths and steps, individual shrubs and trees, as well as clumps of perennials.

Some people like to use the larger scale of 1/4” = 1 foot for detailed work, but usually this is not necessary, and can sometimes actually inhibit easy drawing of bigger spaces.

Smaller scales, 1” = 10 feet or even 1” = 20 feet are used for larger spaces, such as a master plan of a large property.

Using existing drawings
Generally you get the information for your base plan through a combination of getting information from existing scale drawings and taking outside measurements. Existing scale drawings of your property are good starting points for your base plan, although typically they will not be at right scale and will not contain all the information you need.

Your property plan shows the plot boundaries very accurately (which is critical to know for all design work that extends out to the edge of the property). However the footprint of the house and other buildings is often not drawn accurately enough for landscape design purposes. Also property plans are typically drawn at a smaller scale than you want for landscape purposes. Either you can have your plan enlarged by a copy machine, or you just can extract information that will be relevant for your project (such as the lengths and angles of the boundary lines).

On the other hand, house plans from the builder or architect show the footprint of the house very accurately. Typically however these will be at a larger scale than you want for your design work. Either you can have the house plan shrunk, or alternatively just extract the relevant information for your project (like the length of walls and the placement of doors and windows).

The easiest way to convert existing drawings to a scale of 1/8” = 1 foot is to get it enlarged or shrunk at a large format copy machine. (Reprographics in Rutland and Williston provides this service.) Here are the conversion ratios for some commonly used scales:

Measuring and drawing the base plan

The following steps explain the typical measurements you will need for a good base plan. However, actual properties vary widely.

1. Making a Rough Drawing
Find a good-sized piece of paper and make a rough drawing of the shape of the house, plus the relationship of the house to existing paths and other hardscape, beds, large shrubs and trees. Only include what you plan to retain in your final design.

Before going outside find a large screwdriver and two tape measures:

A long flexible tape measure (100’ or 150’)

A medium length steel tape measure (25’ or 30’)

2. Taking spatial measurements for your base plan
Record all your outdoor measurements directly on your rough drawing. I have shown an example using a rough drawing to record measurements.

Start by measuring the house. Label the corners of the house A, B, C, etc. on your drawing. Lay the long tape measure along one wall of the house. Record the total length of the wall. Then, with the tape measure still in place, note the distance from the corner to the edges of each door and window. Call them A1, A2, etc. Repeat this process for each side of the house that will part of your design.

Next measure things that line up with one of the walls the house. If your driveway, path, deck etc. have sides that are parallel or perpendicular to the house, note their widths and positions relative to the house.

The triangulation method is used to measure the position of a tree or shrub (or any other particular spot on the ground that is important). Use the screwdriver to secure the loop of the tape into the ground as close as possible to the base of your tree or shrub. Now measure from that point to two different corners of the house. Make a note of these measurements on your drawing beside the tree or shrub.

The offset method is generally used to measure a curved line, such as the edge of a path or patio. It can also be used to measure a single point near the house, like a lamp or tree. Lay your long tape measure either along the wall of the house or perpendicular to the house. Then, every four feet along the tape measure use the shorter (steel) tape to measure the perpendicular distance out to the path.

Example of using a rough drawing to record outdoor measurements

3. Collect other site information
Make notes on your drawing about other relevant site conditions. These include the location and direction of slopes, soil conditions, areas of sun and shade, any drainage problems, and the location of all utilities (septic, overhead wires, underground wires, etc).

Also note the direction of north and the arc made by the summer sun.

4. Measuring the gradient of a slope
If you have a significant slope it is extremely helpful to know its gradient at several points along its length. The gradient of the slope is defined as the ratio of the vertical rise to the horizontal run of the sloped land, expressed as a percentage.

To measure the gradient of a slope, first get a string level (an inexpensive item at any hardware store), a 4’ stake plus your screwdriver and tape measures. Drive in the screwdriver at the top of the slope and the stake at the bottom. Run a taut horizontal string between them; use the string level to ensure it is truly horizontal. Then with the longer flexible tape measure note the horizontal distance of the string—this is the run. At the stake use the steel tape measure to find the vertical distance from the string to the ground—this is the rise. Divide the rise by the run and multiply by 100, which is the gradient expressed as a percentage.

Finally, use the triangulation method record the exact spots of both the screwdriver and stake on your rough drawing .

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