It is not the intention of this article to give you a complete course in drawing a floor plan. That is a very involved process. In short though, I would like to walk you through the process for your general information.
Most all plans start with a sketch of some sort made by the prospective home builder, or by a professional architect or designer. Usually that sketch is drawn on graph paper so that some sort of scale can be maintained and usually that scale on the grid paper is either one quarter inch equals one foot or two feet.
The first thing that is drawn is the exterior boundary known as the perimeter walls. Weather you are using a drafting board or a CAD (Computer Aided Drafting) program, the process is still basically the same because a CAD program really is nothing more than a drafting board on your computer.
Inside the boundary line, we then draw the thickness of the exterior walls which can either be four or six inches depending on how much insulation will be used and if the construction material is wood or metal studs, with wood being the most common of the two. This is usually determined by the climate of the area the house will be built in. Houses in colder climates would receive more insulation, therefore thicker walls, and those in warmer climates would receive less.
For homes built with other materials, the thickness will vary from one material to the next. For instance if the home is masonry block, the thickness would be four, eight, or twelve inches. With poured concrete the thickness can be whatever is prescribed by the designer, but usually not under six or eight inches thick.
Once the exterior walls are drawn, the interior walls, which are almost always four inches thick, are then placed with careful attention paid to room depths and widths. For instance, a hall that is under three foot wide is of no practical use because the minimum door (from my own experience) into a bedroom should always be no less than thirty to thirty two inches wide and the framing along with the two or three inch trim should always be considered.
A bedroom should always be a minimum of ten feet wide and ten feet deep not including the closet to allow for a bed, dresser and chest of drawers. The closets should be a minimum of two feet deep by three or four feet wide to allow for clothing storage.
The bathroom or bathrooms of a home should be drawn at a minimum of five feet wide to accommodate a bath tub and no less than seven feet deep to allow room for a toilet and sink vanity. A half bath should be a minimum of four feet wide by four feet deep to allow for the sink and toilet.
The living or family room should almost always be at least one and one half times the size of the smallest bedroom to allow for plenty of room for socializing and relaxing while watching television or entertaining guests.
Kitchen sizes will vary but the minimum size kitchen for a two or three bedroom home should be at least one hundred square feet to allow for cooking appliances, dish washing, food storage, and preparation.
If a utility room is on the house sketch, this should be a minimum of three feet deep by five feet wide for a washer and dryer to be placed in it. This type of utility room usually has a five foot wide bi-fold or double door to allow access to both appliances.
And lastly, if we have a garage, the minimum for a single car should be twelve feet wide by twenty two feet deep and an eight foot wide garage door.
Once the rooms are laid out then the doors are placed. The nearest a door should be to a wall is three inches because of the trim surrounding the door casing. The minimum door sizes are as follows: Main Entrance – 36 inch, Secondary Entrance – 32 inch, Bedrooms – 30 inch, Study or Library – 32 inch, Bathrooms – 24 inch, Utility Rooms – 32 inch, Linen Closets – 16 inch, Bedroom Closets – 24 inch, Pantries – 12 inch, Storage Rooms – 32 inch.
These sizes are the preferences of most people I have drawn houses for and may have to be altered to suit the home builder or your client. It’s also good to swing a door to the closest wall for the sake of space. Wherever a door is placed, you can’t have furniture! So door placement is a matter of functionality also.
Windows are very important to the home as these allow light and fresh air into the rooms. For a bedroom, the minimum window should be three feet wide by four feet four inches tall to allow fire egress (a fire escape) should it be needed.
Once these stages are completed then things like dimensions, door and window labels, notes, and electrical can be placed on the plan.