How to Draw a Site Plan for a Building Permit, on a Map

What is a site plan, and when is it asked for?

A site plan is a drawing of your lot seen from above, with every building on it: those that exist, those you are adding and those you are changing. It answers the question the reviewer reads it for: where does the project sit on the lot, and how far is it from the lot lines and from the neighbors?

It is asked for whenever work needs a building permit or a similar approval: an addition, a new house, an accessory building, a deck, a pool, sometimes a fence. Depending on the city or county, it goes by other names, and the exact requirements differ from one building department to the next.

Because those requirements vary, treat this guide as a general method. Before you draw, read your building department’s checklist for the permit, or ask which drawings, at what scale, with which details, they expect.

What a site plan usually shows

The exact list depends on the permit and the department. Here is what such a plan commonly contains, and what the reviewer looks for.

• The lot lines, with their lengths, and a north arrow.
• The existing buildings, those you keep and those you remove, with their dimensions.
• The proposed buildings or additions, dimensioned, set apart from the existing ones by a line style or a color, and a key.
• The distances from each building to the lot lines, because those are the setbacks the zoning rules control.
• The access from the street, the driveway, parking and the exterior work: fence, gate, deck, pool.
• Trees kept, removed or planted, and any hedge on or near a lot line.
• Neighboring buildings next to the lot, when they affect your project.
• Easements and utility connections, such as water, sewer and power, and, where required, ground levels and heights.
• The scale of the drawing, or a graphic scale bar.

Plan² draws most of that on a sheet, but not levels or heights: those are coming, and until then you add them yourself, as explained below.

What you need before you start

• The deed, the recorded plat or the county parcel map of your lot, or a survey if you have one: it gives the length of the lot lines.
• Your closing documents, which usually state the lot size.
• The local zoning rules and any homeowners association covenants, to know the setbacks from the lot lines and the street, the maximum height and the permitted lot coverage.
• A long tape measure or a laser distance measurer to check the distances between the buildings and the lot lines.
• The project itself, with its dimensions and its position: a sketch is enough to start.
• The heights of the existing buildings and of the project, and the route of the utilities, to add to the drawing.

Site plan conventions: scale, orientation, key and dimensions

Worked example: the demonstration site plan

The figure shows the demonstration house on its lot, seen from above. The lot measures 83′ 11¾″ by 49′ 2½″, with the dimensions marked on two sides. The house and its garage form one block 51′ 2¼″ wide, dimensioned above the front wall, set towards the street. The street is to the north: the hedge stops there to make room for the gate, which leads to the garage door.

The distances to the lot lines are measured from the outside face of the house walls to the inside face of the fence or hedge: 3′ 5¼″ from the west fence, 10′ 0″ from the street hedge to the north, 15′ 3″ from the south fence and 28′ 4½″ from the east fence, behind the garage. The patio is laid against the south wall, the pool stretches across the southeast, and two trees are shown.

At the bottom left, a 15 ft graphic scale lets you check lengths on a copy, and at the top right the arrow shows north. For a real application, you would still add heights, a key for existing and proposed work and anything else your department lists.

Mistakes that get an application sent back

• A plan with no scale and no north arrow, which cannot be read at the counter.
• Missing or approximate distances to the lot lines: the reviewer must be able to check them on the drawing.
• Existing and proposed work mixed up, with no key to tell them apart.
• A lot drawn from an aerial photo or a sketch with no measurements, instead of the recorded plat or a survey.
• A neighboring building or a nearby tree left out, when it bears on the setback.
• A site plan that does not match the other drawings: elevations, sections and the written description must all tell the same story.
• A missing document on the checklist: in most departments, the application is returned as incomplete and the review period does not start.

What Plan² prepares, and what is left to add

Plan² draws the 2D base and the sheets built from it: the lot lines, the house, the addition, the pool or the shed, the trees, the access and the connections to the utilities, drawn dashed with what each ends on in the street. The Site plan export gives an overview of all the properties of the project, one sheet per property to the scale you chose, and one sheet per lot if you divided the property. Each sheet carries the house hatched, the distances to the boundaries, the access, an information box with areas, a scale bar, a north arrow, a legend and a title block.

It does not draw sections, elevations, levels or heights: those are coming. It does not fill in an official form, and it does not check your project against the zoning rules. In the United States the lot boundary comes from your plat, deed or survey and is drawn by hand, because the parcel import and the building outlines work in France only, and the map is built on OpenStreetMap. Plan² does not replace a survey: the accuracy of a boundary is the accuracy of the document you took it from. Always check the exact documents your local building department asks for, since they may ask for more, such as a stamped survey.

Drawing your site plan step by step in Plan²

1. Open Terrain mode

   In Plan², open Layers and switch to Terrain mode. The guided flow has four steps, Address, Parcel, House and Around, and you can skip any of them. Search for the address of the lot: the map is opt-in, so a consent card asks first, and nothing is sent before you accept.

2. Draw the lot lines

   Tap or click each corner of the lot, from the recorded plat or your survey, then Finish. You can type the length of each side in feet and inches. If the property covers several parcels, add another property to the project: each one has a name, an address and a parcel reference.

3. Place what exists

   Draw the house and the outbuildings already there at their real position: trace the walls, then place doors and windows. Where the map shows building outlines, which is France only, you can start from the outline instead.

4. Add the project

   Draw the addition, shed or pool, and name each wall and item of the project, for example “Proposed addition”, so you can pick them out.

5. Add the street, the access and the connections

   Draw the street, the access (driveway or gate) and the neighbors that matter, then the connections to the water, sewer and power networks. Check the distances from the house to each lot line shown in Terrain mode against your tape.

6. Export the Site plan

   Choose File, then Export…, and pick Site plan. Choose PNG or PDF, the paper and the scale from 1:50 to 1:500, switch on the map backdrop if you want it under the sheet, and look at the live preview. Check a known dimension on the print, then add what is still missing, such as heights and your department’s own notes. Keep the JSON file too, so you can change the plan later.

7. Divide a property into lots, if the project needs it

   If the project splits the property, use Divide into lots, draw the cut from one boundary to another and read the area of each lot. The areas come from your drawing: they are a sketch, not a survey, and the Site plan export then gives one sheet per lot.