How to Scale Building Blueprints

Blueprints are graphical reproductions of buildings and other structures. They are created to provide the builder with an idea of how an infrastructure should look. These documents serve as guides to engineers, architects, carpenters and everyone in the construction industry because they contain instructions on how big each part of the building is going to be. This is why it's important for blueprints to also contain precise measurements for every part of the structure.

Blueprints contain miniature drawings of a building so the actual measurements are scaled down so they would fit in the paper. Simply put, scaling a building blueprint means creating a floor plan that that is proportion to the structure that is going to be constructed.


Step 1

Learn how to read the scale. The scale is like a ruler that has divisions on it to represent standard proportions to distances. Your need to understand the scale ratios for you to be able to scale a building blueprint accurately. For instance, if you're going to draw an object following its actual size, the scale is going to be 1:1. A unit measure of the drawing equals a unit of the actual object. If you're going scale it down, you will have to use a ratio that will make it smaller, for instance, drawing a structure at a fifth of its actual size (1:5).

Step 2

Determine a scale to use for the building. Logically, the bigger the object really is, the smaller the scale is going to be. For instance, a house might use a scale of 1:1/4 – that is, for every foot of the actual size of the building, you measure a fourth of an inch on paper. So four feet on the building, is equivalent to an inch on the scaled building blueprint.

Step 3

Convert the actual measurements of the building according to the scale ratio of your choice. If you're going to draw a 1:1/4 building blueprint, you need to select the side of the scale rule that is marked 1:1/4.

Step 4

Create the scale using the graph paper. Following the 1:1/4 scale ratio, you recreate the ruler on the graph paper this time designating the how big one foot of floor space is supposed to be. On a scale of 1:1/4, measure ¼ inch on the graph paper and mark it as 1 foot.