Drawing for roofing

This page and the next one is a very condensed, bare bones guide to technical drawing for roofing.

Anyone who wants to understand the finer points of building roofs first needs to be able to read and understand construction drawings.

Further pages in this series will show you how to extract information from the drawings and turn it into the type of nuts and bolts details that will allow you to build any roof.

Drawing for roofing - Planes

Drawing takes many forms from a few marks with a burnt stick, (charcoal), to highly complicated CAD drawings produced on a computer.

No matter what the process the end result of any drawing is to provide information. In the case of the drawings on this website I have drawn them to pass on information from me to you. You in turn may have a set of drawings done by an architect to allow you to get approval and then build your new project.

When using drawings for construction we have to go to some trouble to present them in a clear and lucid fashion. Over many years the process has developed and it is known as technical drawing.

Tech drawing is based on standards that we all have to learn (and indeed we have to comply to) so that in effect we are all "talking the same language".

drawing planes

• Planes are imaginary flat surfaces that have no boundaries.
• They can be inclined in any direction, and at our convenience they can be placed in any position in relation to the object that we wish to draw.
• So if I want to describe an object to you, as in the drawing above to help me to do it I imagine directly under it a totally flat, level and endless surface that is known as The Horizontal Plane.
• I also imagine a truly vertical surface directly behind and parallel to the surfaces of the object that I wish to draw. This is called A Vertical Plane.

Drawing for roofing - Plans and elevations

Plans and elevations

These are the main methods that the architect or draftsman uses to provide accurate information about a three dimensional object (a building or part of it) on a flat surface like a sheet of drawing paper.

• Plans or plan views. (Not to be confused with the collective term, as in "a set of plans"). These are drawn as though we are looking from directly above the object and as if what we see is projected down onto the horizontal plane. Even if the block of land is sloping no account of this is taken in plan views.
• In the sketch above I have drawn two plans in one. One of them the outline of the two roof surfaces drawn dotted, and the other the outline of the walls.
• Plans contain a wealth of information and of importance here are roof plans .
• On a roof plan we can get accurate information about horizontal surfaces only.
• Horizontal members like ridges and eaves are shown truly in plan projection.
• Sloping surfaces are not represented correctly in plans.

• Elevations. Likewise if we imagine looking at the face of a building and then projecting what we see onto an imaginary vertical plane that is parallel to the face that we want to draw, then we will get a view which is called an elevation.
• Elevations round out the information started by the plans and on some jobs they complete the information that the draftsman gives us.

Drawing for roofing - Sections

sections

Only the most simple buildings can be drawn with just the standard plan and elevation views. Most times we need to show something that is hidden.

To do this we imagine a plane slicing though the building and also removing the part that is obstructing our view. What we see then, when it is projected onto a plane is called a section.

• Most of the time sections are drawn on vertical planes but occasionally they are used to show details of surfaces that are angled to the horizontal.
• In general sections are drawn at a larger scale than the standard elevations.
• They typically carry a lot more detail and are they are very important to extracting roofing information from a drawing.

• Drawing for roofing: TOP
•  
• << BACK: Roof calculations
• Scale in drawing: NEXT >>