When we need to make alterations or additions to an existing building, the drafter finds that they need an accurate drawing of the structure as it stands. This is called an As-Built drawing. If the original drawings of the building aren’t available, it is then necessary that we measure and recorded it in some quick and accurate manner so that workable plans, elevations, etc., can be drawn. The amount of detail needed in these drawings and the care with which we make them is determined entirely by the new work to be added to the building and will vary with each instance.
The first sketch is made on grid paper. This paper is ruled vertically and horizontally with lines 1/4″ inch apart forming 1/4″ inch squares. As the sketches are usually made at a scale of 1/4″ = 1′ – 0″, the plans, elevations, etc., can be more easily drawn on this paper with good proportions because each small space represents one foot at this scale. The paper should be fastened to a piece of cardboard or other lightweight board so that it can be easily carried and marked on.
A tape measure will be needed for making the measurements. A digital camera is also a handy piece of equipment because you can record exactly what the subject that you are drawing looks like in relation to your sketches. You need to be careful to make your notes as complete as possible from the beginning because if anything is left off the sketch, time may be wasted in having to repeat trips to the building the retrieve the missing information.
The first thing we draw are sketches of the floor plans. These should be measured and recorded as completely as possible. These should show all main dimensions of rooms, the location of stairways with the number and dimensions of the risers and treads. Then the thickness and material of all walls, the width, and location of all wall openings and then any other features such as heating and plumbing equipment, and so on are sketched. Take as many photo’s a you can. You can never have too much information to complete your as-builts.
In recording the vertical dimensions, the story heights should be noted first. This can be done by dropping your tape measure down through a stair well where possible. You can also measure on the outside wall from sill to sill of the windows and then adding the sill to floor dimensions of the lower story and subtracting corresponding dimensions from the upper story. And again, photograph everything possible on the exterior.
Once all this information is compiled along with notes on exterior finishes, roof pitches, grade heights, etc., the sketches can be turned into exact drawings of the structure that is to be remodeled. Form the point the additions can be made to the building and construction drawings can be completed.
My name is Tim Davis and I draw architectural and mechanical plans for a living. I also teach others how to draw house plans, site plans, mechanical and shop drawings and other types of drafting that I have been trained to do in a virtual classroom on the internet at http://draftingschool.net/