Design Your Own House Plans: Step by Step Guide

You can design your own house plans by working through a fixed sequence: define what you need, study the lot, sketch the room relationships, set the footprint, lay out the rooms, place stairs and openings, design the roof and then produce dimensioned drawings. Doing it in this order prevents most of the costly rework that happens when people start by drawing their favorite room and try to fit the rest of the house around it.

You do not need to be an architect to make your own house plans, but you do need exact dimensions and a way to check the design in 3D. A house planning program such as Plan7Architect Pro handles the technical part, from automatic dimensions to sections and plan sheets, so you can concentrate on the design itself.

This guide walks through every step with the typical numbers I use when I plan a house. Before you start, it helps to know what homeowners are allowed to draw where you live; our article can I draw my own house plans covers the basics.

Step 1: Write Down What the House Must Do

Every good plan starts with a list, not a drawing. Write down:

• Number of bedrooms and bathrooms, and who uses them
• Rooms you need beyond that: office, laundry, mudroom, pantry, guest room, garage
• How you live: open kitchen or separate, formal dining or not, one level or several
• Your budget and the approximate floor area it allows
• Things you want to avoid from your current home

Then give each room a target size. The following values are practical starting points:

Our room size guide goes into each room in more detail.

Step 2: Study the Lot and the Rules

The lot decides more about your house than any room list. Find out:

• Property lines and setbacks from the front, side and rear lot lines
• Maximum building height and lot coverage
• Slope of the terrain and where water drains
• Where the sun comes from and where the best views are
• Access for the driveway, utilities and the building site

Subtract the setbacks from the lot and you get the buildable area. Your footprint has to fit inside it. On a sloped lot, the terrain also decides whether a walkout basement or a split level makes sense.

Step 3: Sketch How the Rooms Relate

Before you draw walls, draw bubbles. Put each room on paper as a circle and connect the rooms that need to be next to each other: kitchen to dining, dining to terrace, entry to coat closet, bedrooms to bathrooms. Group the house into zones:

• Public zone: entry, living, dining, kitchen, guest bathroom
• Private zone: bedrooms and bathrooms
• Service zone: laundry, mudroom, storage, garage, mechanical room

Place the zones on the lot: living areas toward the sun and the garden, the garage toward the street, bedrooms away from noise. This rough diagram is the most important design decision you make, and it costs only a pencil.

Step 4: Set the Footprint

Add up the room sizes, then add about 15 to 20 percent for walls, hallways and stairs. That gives you the gross floor area per level. A simple rectangle or L-shape is cheapest to build; every extra corner adds cost to foundation, walls and roof.

Now draw the exterior walls in your software with exact lengths. Remember that exterior walls are often 6 to 12 inches (about 15 to 30 cm) thick, so the inside of the house is smaller than the outer dimensions. Our article on wall thickness lists typical values.

Step 5: Lay Out the Rooms

Divide the footprint according to your bubble diagram. Keep these clearances in mind:

• Hallways about 36 to 42 inches (about 90 to 110 cm) wide
• Interior doors usually 30 to 36 inches (about 76 to 91 cm) wide
• At least 36 inches (about 91 cm) of walking space around a bed
• 42 to 48 inches (about 107 to 122 cm) between kitchen counters

Stack bathrooms and the kitchen close to each other where possible. Shorter plumbing runs save money and make the plan simpler.

Step 6: Place the Stairs, Doors and Windows

A straight stair for an 8-foot ceiling (about 2.4 m) usually takes a space of about 3 by 12 feet (about 0.9 by 3.7 m) in plan, plus landings at top and bottom. Place it early and design the upper floor around it. Our guide on calculating and drawing a staircase shows the calculation.

Doors should not open into each other or block furniture. Windows should serve the room, the furniture and the facade at the same time, which is easiest to judge in 3D.

In Plan7Architect, doors and windows create their openings automatically when you place them, and the 3D view updates at once. That makes it easy to try a window at a different height or a door on another wall and see the effect immediately.

Before you place the stair in your plan, check how many risers and how much run it needs for your floor-to-floor height.