Measuring the House
Always start by measuring the outside of the first floor of the house. Begin measuring from any corner and work your way around the house. Move counter-clockwise around the house. It is best to do this the same way every time that you do it to avoid easily made errors and to make it easier to retrace your steps to track down any errors. Measure the exterior of the house to the nearest inch. If you use an “engineer’s scale” fiberglass tape (which is recommended), measure the exterior and interior walls to the nearest 0.05 foot, for example 23.25 feet. This will make your calculations considerably easier later.
If you can't get close to a wall because of landscaping or other obstacles, use your screwdriver to anchor the 100-foot tape on the ground away from the wall.
Draw your sketch and the write down the corresponding dimensions on the graph paper as you go, with each square representing one foot. For example, if the exterior dimension is 3.45’, you will draw a line that is 3 squares long. If the dimension is, 3.50’, draw your line 4 squares long. (Always round up to the next full number if the dimension is 0.50’ or greater.) As you move around the house making your sketch, place the exterior doors and chimneys in their approximate locations on your sketch. It is also helpful to make notes on your sketch of which walls have full height second floor walls that are the same as the walls on the first floor. It also may help you to include in your sketch where the porches, stoops, screen porches, patios, and other outdoor areas are located on your drawing as you go.
When you have completed your first floor exterior drawing, use your calculator to “square” your drawing. To square your sketch, add up all of the dimensions of parallel walls on each side. Opposite sides will be equal. If they are not, check for errors by re-measuring any of the walls to find your error.
When you are finished measuring the outside of the house, go inside and decide what to include and what not to include on each level. If the house has a garage, it is not to be included in the heated living area calculations. You must measure the garage out so that you can calculate this area separately.
You will draw a separate floor plan sketch for each level in the house. If there is a second or upper level, measure that area from the inside. To do this, go to the second floor and, when possible, begin on a corner on which you have a corresponding first floor corner. Begin your sketch from this point. Remember, you are measuring the EXTERIOR dimensions of the second floor so you will adding to the interior measurements the wall thicknesses to get the exterior dimensions. (0.40’ to account for the thickness of an exterior frame wall, 0.40’ for interior walls with finished drywall, and 0.70’ to account for exterior masonry veneered walls). These wall thicknesses are estimates for typically built residential walls. It is more accurate to try to determine the actual thicknesses of the walls in a house when possible. To do this, find a section of the house that has 2 outside corners. Make a note of the length of this distance. When you go inside, measure the interior length between these outside corners and subtract the distance measured on the outside measurement. Divide this difference by 2 and you now have a more accurate estimate of the wall thicknesses. This method will work in most instances where the exterior walls are of the same materials, such as vinyl siding or brick veneer.
When there are openings to the floor below, such as in an open foyer, subtract the opening from that level.
When there are stairs, include them on every level they serve, that is, count the floor area of the staircase on BOTH the first and second floor areas. Be sure to include the stairs in the second floor area when measuring out an open foyer.
As you gain experience measuring houses, you will find a number of difficulties that will present themselves with different house designs. Some two story houses and one and a half story homes have very few second floors exterior walls that will line up with the first floor exterior walls. It is very important before you begin measuring the upper floors of any house, to identify which of the interior walls are also the exterior walls of that level. I find it helpful to walk around and try to identify these walls before I begin the measurement.
For split-level designs, measure each level. It is helpful to measure the lower and main levels from the exterior together and then separate the levels by getting the interior measurements on each level once you have gone inside. You will measure the upper level separately from the interior of the house.
When measuring a basement, separate the finished basement area from the unfinished areas. Even if the basement is a “daylight” finished basement, when applying the ANSI Standard to a residential measurement, below-grade areas are always reported separately from the above-grade areas and the below-grade area is NEVER included with the above-grade heated living area. Most MLS systems also require that the finished and unfinished below-grade areas are reported in such a way that these areas are clearly labeled as "Finished Basement" or "Finished Lower Level", even if the total finished square footage reported in the listing includes these areas.
Exclude any areas, such as porches & converted garages that are not finished or heated the same as the rest of the house (see the guidelines of “Heated Living Area” from the NCREC).
(from How to Measure a House by Ed Odham © 2005-2012)
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