Technical Drawing: Plans
In part one of our technical drawing series we looked at Layout, and part 2 explored Labelling and Annotation. In this part of the technical drawing series, we will look at Plans.
Depending on the nature and complexity of a project, the floor plan can contain simple or complex information. It may be that a number of different floor plans are needed to represent all of the information required, or that just one floor plan will suffice. It is also worth mentioning, that floor plans are required to show a different level of information depending on the stage of the project. For example, at early planning stages, plans tend to be more basic, providing necessary information to a planning department in order for them to decide whether they will grant permission for the project. A construction drawing, on the other hand, will required detailed information on how the building will be constructed, focusing on many aspects of the project.
When you start drawing your plans it is important to note the stage of your project, and what information you are conveying, and to whom.
Types of Plans
Architectural planning drawings
Let’s start with the basic floor plan. A planning drawing will be required by a planning department in order for them to decide whether to approve the application.
The floor plan must contain some standard elements that will help your reader understand the drawing. Some of these basic requirements are:
- Main openings in walls (window and doors)
- Partitions or internal walls
- Door swings
- Room names
- Grid reference if relevant
- Fixed furniture
- Loose furniture suggestion
- Sanitary fittings
Separate from the building itself, the drawing must show a north point, which allows the reader to orientate the building, along with a scale bar. It is also important to note on the plan the entrance to the building using an arrow and “IN” or “ENTRANCE” label.
The scale at which you present the drawing will dictate how much information will be shown on the drawing. For example, you could consider including dimensions, annotations or labels where necessary, hatching or shading, section markers. This information would most certainly be included in construction drawings, but may not be required at this stage.
Architectural Construction Drawings
Construction drawings need to provide more detailed information to the reader and will be used to gain building regulation approval, and later to construct the building. Due to the amount of information displayed, it is sometimes necessary to divide the general arrangement floor plan into elements so that the information remains clear to the reader. For example, services, such as mechanical and electrical services may be displayed on a separate floor plan for clarity.
A small project can be displayed at a larger scale on the paper, and therefore it is often possible to keep all of the information on one plan.
If a complex project requires separating into a selection of drawings, the content of these could be:
Primary elements (walls, frames etc)
Secondary elements (doors, internal walls, window information etc, suspended ceilings)
Fixtures and Fittings
The Floor Plan
A floor plan is considered a horizontal section of the space at about 1 – 1.2m height. Anything above the 1 – 1.2m height, should be shown as a projected line of the element above this height, using a dashed line. An example of this may be a kitchen. A standard floor plan will show the kitchen worktop, sink, hob, but the elements above the 1m line, ie, wall cupboards, cooker hood etc will be shown as a dashed line, to indicate their position. It is fair to assume a higher cutting plane in cases where there is a tall or high window to ensure it is included on the plan.
Let’s take a look at the main elements we are representing on a floor plan:
Structural and non structural walls
At planning stages we may only show the walls as simple thick lines or hatch filled lines, but in later stages of design, we will show the walls with hatch, denoting the material used in the construction.
In some cases, a key may be used to demonstrate the different wall build ups, and a simple number reference added to the plan.
Walls are drawn with heavy lines so that the spaces stand out clearly, built in furniture, and other objects are drawn with medium lines which shows a level of hierarchy. In some cases, the furniture can be drawn in a light grey (if using cad) which gives the suggestion of furniture layout without detracting from the construction information in the drawing.
Doors and windows
For planning drawings we will display a simple door with swing showing which way the door will open and which side of the door the hinges will be. Similarly, a window will be displayed in a simple manner – like the images below.
For construction drawings we require more information about the doors and windows. These can be represented in a number of ways. Typically, the doors will be annotated with a door number, and possibly further information. The doors will correlate with the door schedule, which will list out all of the doors in the project, by number, and give further details of the door – ie, fire rating, dimensions, glazing, ironmongery and so on.
Windows will also be displayed with a number and possible additional information (dimensions or perhaps sill height). The windows will again correlate with the window schedule, where each window in the project is listed out by number, with further details. Some window and door schedules include examples of how the window is displayed in plan, elevation, and in 3d, but we will get to that later.
Stairs are shown on floor plans in different ways according to the complexity and detail required. A stair will show an UP arrow, showing the direction travelled to go up the stairs. If we are looking at a floor plan at ground level, with a stair going to first floor level, the lower half of the stair will be drawn using a solid line, at the point we go above our 1m height, the stair will be drawn as a dashed line, or with less detail. Break lines are also used to distinguish between different stairs. Some examples of stairs are shown below.
When showing a stair from the first floor, going down to the ground floor, we still show the upward arrow. The lower part of the stair is then greyed out.
Similar to stairs, ramps are shown with an arrow in the upward direction. The ramp can also be labelled with the gradient, and any other relevant information.
Our floor plans will show finished floor levels, changes in levels, and ceiling heights. These can be demonstrated in a number of ways. An area of the plan that is clear to annotate, can simply have the word FFL: 0 (finished floor level), or a symbol marker can be used, see below.
If there is a small level change on the same floor plan, it is good practice to show the finished floor level for both sides of that level change.
For ceiling heights, it is common to see CH +2400 (ceiling height 2400mm). However you choose to show the levels, make sure you remain consistent throughout your drawings.
The floor plan should include dimensions of wall locations, wall thickness, openings and distances between structural elements.
How these are displayed can very. There is a fine line between providing relevant dimensions and complicating the plan with necessary information.
Dimensions between walls can be from the structural frame (ie, excluding finishes) or from finished surface. The structural option gives the builder the exact location of studs, columns, beams etc. Make sure the dimensioning option used is displayed on the drawing notes. Centre lines are also used for dimensions.
Dimension lines are drafted in a lighter line weight as not to be confused with structural elements. Where possible dimension lines should be placed externally, to keep the inside of the building uncluttered for other information. Internal dimensions will be placed within the building.
Generally, dimensioning a building will require two or three continuous dimension lines to locate exterior walls, interior walls, windows, doors, and other elements. When placing the dimensions on the exterior of the building, the outermost dimension will give the overall building dimension. The next line, moving inward toward the plan, will provide wall locations, and doors and windows. If required, a third dimension line can show other details.
If your dimensions are cluttering the floor plan too much, you could consider having a separate dimensioned plan, and keep just a few key dimensions on your main plan. It is not necessary to dimension everything in the plan, make sure you don’t dimension the same measurement twice or over clutter with unnecessary dimensions.
Similar to the kitchen unit example we used earlier, any items overhead, such as changes in ceiling height, can be displayed using a dashed line, usually with a label to provide further information.
Demonstrate wheelchair access / turning circles, where appropriate, showing a dashed line circle with dimension according to building regulation requirements.
Floor Plan Checklist
Drawing sheet title block
- Drawing Title
- Scale and north point
- Doors with directions of swing
- Door and window labels/numbering
- Room names / numbers clearly labelled
- Stairs clearly indicating ‘up’ or ‘down’ with appropriate dashed lines above 1m
- Overhead dashed lines indicating objects or ceiling changes overhead
- Accessibility information, such as turning circle for wheelchairs
Annotations and labels
- Floor levels
- Changes in levels, steps, stairs and ramps
- Label main components or reference them to a key/legend
- Note ceiling heights / changes in height (if project is small and doesn’t require reflected ceiling plan)
- Dimension wall locations (and note whether the dimension is taken from face of wall, centre line or other surface)
- Dimension walls to structural components
- Give angles in degrees if necessary (ie, walls not at right angles)
- Give diameter of any circular elements, curved walls or similar
- Dimension stairs
- Dimension openings
- Dimension built in items, cabinetry, partitions (or on separate plan)