Ideally, the attic floor square footage would be measured at the attic floor length x width (regardless of roof pitch, by the way).
Building Code defines the attic as length x width, floor of the attic. That produces a "square footage" number. That's also how ventilation manufacturers generally define the size of an attic. It's the most accurate measurement of the space we are trying to vent.
This rule means, at least half of your attic space must be 7 feet high by 7 feet wide, with a total of 70 square feet. Keep in mind, codes vary from place to place, but for using the attic as an actual room, this rule typically applies.
A fully finished attic is 50 to 55% of the house's ground floor square footage. This type of attic is ready to function as a livable area such as a bedroom or home office.
If it is, then any part of the room with a ceiling of 5 feet (1.52 m) or higher should be included [source: Boddy]. If not, you shouldn't include any of that space. As for rooms in the house that aren't finished, like basements or attics, they should not be included in the total square footage.
How to Measure Square Footage of Your Home in 4 Steps. The gross building area can be easily calculated by measuring the exterior walls of your home to calculate the area, and multiplying by two or more for additional stories. However, the most important measurement only looks at the space that's livable inside.
Attics are typically used for storing items, but they can also be transformed into livable spaces such as an extra bedroom, a playroom, or home office. There are several types of attics, including unfinished attics, finished attics, knee wall attics, and scuttle attics.
Standard openings are 22.5” x 54”, but some homes have wider openings. Conversely, some homes have smaller openings (or hatches). It's important to understand the opening size you have or will create to ensure you select the correct attic ladder product for your home.
Attic conversions are popular right now. They don't require you to add on to your home, but they can give you extra space and even another bedroom or bathroom. Although they tend to cost less than a home addition, it's still worth researching what you can expect to pay for your attic renovation.
BUILDING CODES
Regulations vary from county to county, but most attic conversion building codes require: A minimum of 70 sq. ft. of floor space.
Renovating an attic can be a great way to add space and value to your home. Typically, the cost can range from $10,000 to $50,000. This wide range depends on many factors, such as the size of the attic and the complexity of the design you choose.
For most wiring, this is possible but may not always be possible as there will inevitably be light fixtures that are installed throughout the ceilings below. Electrical wiring should be installed to minimize the likelihood of damage, impact, or water ingress.
According to the International Residential Code (Section R806. 2) and International Building Code (Section 1202.2. 1), attics require a minimum of 1/150 of NFA but can be reduced to 1/300 if certain conditions are met.
Next to your attic joist's size, the joist's spacing is important as well, especially in terms of flooring finishes and materials. To be able to install flooring, an attic's standard joist spacing should be 16 inches on center (OC), meaning the measurement is taken from the center of each joist, not from edge to edge.
and 30 inches high must have an access point. The minimum attic access size is 22 by 30 inches. A standard attic access size is 22 1/2 by 54 inches.
Grab your tape measure, and measure the length and width of each room, hall, stairwell, closet, etc. whose ceilings touch the attic floor. Multiply the length x width, and you will arrive at ft2, (square feet). Total all your answers, and you will arrive at a good estimate of your attic size.
Here's a quick summary of what most local building codes require: Floor Space: finished attic spaces should be at least 70 square feet. Width: the living space should be at least 7 feet wide or long. Ceiling Height: at least 50% of the room's usable space needs a clearance that's 7 feet high.
Stairways accessing a loft shall not be less than 17 inches (432 mm) in clear width at or above the handrail. The width below the handrail shall be not less than 20 inches (508 mm).
A garret is a habitable attic, a living space at the top of a house or larger residential building, traditionally small with sloping ceilings. In the days before elevators this was the least prestigious position in a building, at the very top of the stairs.
Many homeowners believe they have only one. But there are actually different types of home attics (in addition to that big one upstairs). And these attics can play a huge role in your home's comfort and efficiency.
Because of the nature of an attic's purpose, you must remodel the space to prevent an accident from happening. One of the most important part of remodeling this space is to use the right type of attic flooring. From a construction standpoint, the attic is important to provide insulation and stability to your house.
Measure the length and width, in feet, of each room. Then, multiply the length by the width to calculate that room's square footage. For example: If a bedroom is 12 feet by 20 feet, it is 240 square feet (12 x 20 = 240).
The upstairs areas are included, but open spaces, such as the vaulted area seen in the photo here, are not. The foyer area shown is only counted once.
Any porches, terraces, unfinished basements, exposed to the elements or lacking heating/cooling would not be considered livable and therefore not be counted as part of the square footage of a home.