How to read a floor plan
You do not need a drafting background to judge a house plan properly. Learn the handful of conventions below and you can evaluate any plan set with confidence, well before you hand it to a builder.
What is in a complete plan set
A construction set is far more than a floor plan. Every Planbarn set includes the drawings a builder needs to price and build the house.
Floor Plans
Dimensioned layouts of every level, showing room sizes, wall positions, and door and window placement.
Exterior Elevations
Each side of the house drawn to scale, showing heights, rooflines, materials and trim detail.
Foundation Plan
Slab, crawl space or basement layout with footing sizes and load-bearing points marked.
Building Sections
Vertical cuts through the house showing floor-to-ceiling heights and how the structure stacks.
Roof Plan
Overhead view with pitches, ridges, valleys and overhang dimensions.
Electrical Layout
Outlet, switch and fixture placement for every room, with panel location noted.
Reading a plan, step by step
Start with the scale
Most residential plans are drawn at 1/4 inch = 1 foot. A scale ruler lets you measure anything on the sheet that is not already dimensioned. Never scale off a printed PDF that has been resized, always work from the written dimensions.
Walk the plan in your head
Trace your morning: front door to kitchen, bedroom to bathroom, garage to pantry with shopping bags. Awkward layouts reveal themselves fastest when you move through them mentally rather than looking at the shape.
Check the door swings
Doors are drawn as a quarter-circle arc showing which way they open. Look for doors that collide with each other, block a light switch, or eat the corner of a room you wanted for furniture.
Read the window placement
Windows show as thin breaks in the wall line. Note which elevation each room faces, then think about morning light in the kitchen and afternoon heat in the west-facing living room.
Sanity-check the dimensions
Bedrooms want 10x10 as a workable minimum, primary bedrooms 12x14 or better, and main living spaces at least 12x16. Hallways at 36 inches feel tight; 42 inches feels generous.
Common plan symbols
The shorthand you will meet on almost every residential drawing.
Room dimensions worth knowing
Useful reference points when you are judging whether a room will actually work.
| Space | Workable | Comfortable |
|---|---|---|
| Secondary bedroom | 10 x 10 | 11 x 12 |
| Primary bedroom | 12 x 12 | 14 x 16 |
| Living / great room | 12 x 16 | 16 x 20 |
| Kitchen work zone | 10 x 10 | 12 x 14 |
| Dining area | 10 x 12 | 12 x 14 |
| Hallway width | 36 in | 42 in |
| Single garage bay | 12 x 20 | 14 x 24 |
Dimensions in feet unless noted, measured wall to wall.
Ready to find your plan?
Now that you can read a plan set properly, browse the catalogue and judge each design on its merits.