If you can’t read a blueprint, it’s not your fault. The skill depends on an innate spatial aptitude, and if you were born without it, you’ll never be able to visualize a space by looking at a plan. Life can be cruel. That said, there are a few drafting conventions that can trip up even the spatially adept; understanding these will at least clear your way.
If you thought the arcs attached to the doors in your plans were a design motif your architect dreamed up, you’ll be disappointed by their absence from your finished house. These are door swings. They aren’t representational but instead indicate the sweep of the doors when opened and closed. Door swings are informative, showing you not only where the hinges are located (the center of the arc), but whether the door will bump into that armchair you wanted to squeeze into your bedroom.
Everyone knows windows are in walls, but distinguishing in plan between the two is counterintuitive. The convention of drawing walls with just two lines and windows with a half dozen defies expectations of opacity vs. clarity, thick vs. thin. The window lines are a faithful depiction of a window’s sash, glass, and sill, which does in fact bulge beyond the face of a wall. But walls are so basic to a draftsman that rendering the masonry, studs, wallboard, pipes, and wiring in each would be unfeasible—hence two lines.
Too Many Lines
If a drawing still looks like a tangle of lines to you, try squinting your eyes to focus only on the thick lines. The closer an object is to the viewer, the thicker the line will be. In general, thicker lines indicate features that are more important to your understanding of the spaces. For example, walls are demarcated by thick lines, stair steps by thin lines