NCIDQ IDPX EXAM | INTERIOR DESIGN PROFESSIONAL EXAM
2026/2027 LATEST UPDATE | QUESTIONS AND VERIFIED ANSWERS
| GRADED A+
Carpet -
CORRECT|ANSWER
Length needed in stripes. (Ft)
Add together and divide by 3' to get yards.
Times by 4' for waste.
ROUND UP.
Carpet on Stairs -
CORRECT|ANSWER
Times number of risers by inches (height). Times
same number of treads by inches (depth)
Add those numbers together.
Add 1" per riser for nosing and wrapping.
Divide by 12 to get feet.
ROUND UP.
Take (ft) number and times by width of stairs.
Divide by 9 to get square yards.
Wallpaper (plain, residential) -
CORRECT|ANSWER
Calculate perimeter of room in feet.
Multiply by ceiling height.
Add 20% for waste.
Minus 15 sq. Ft per 1 door or 2 windows.
Divide by 36 to get how many single rolls.
ROUND UP.
Wallpaper (w/repeat, residential, half drop) -
,CORRECT|ANSWER
Divide height to be covered by repeat. (Minus any base or crown)
ROUND UP.
Take that number and times it by the repeat.
Convert inches to feet by dividing by 12.
Calculate the perimeter of the space in feet.
Times that by modified ceiling height (from before).
Add 20% for waste.
Minus windows and doors.
Divide by 36 for SR or 72 for DR.
Wallpaper 54" wide (commercial) -
CORRECT|ANSWER Calculate
perimeter of room.
Multiply perimeter by height.
Take no deductions for windows and doors unless o we 54".
Divide by 13.5 to get yards.
Times by 3 if linear feet are needed.
Times by $ if cost is needed.
Calculating Draperies (no pattern) -
CORRECT|ANSWER
Divide window width by 3 to get stacking space.
Add window width, stacking space, return and overlap together.
Return & Overlap = 12"
Multiple this number by fullness factor.
Divide by fabric width (54").
ROUND UP.
Determine cut length by multiplying height of window by 12 to get inches.
Add header and hem. (Given)
Take panel number times it by cut length number and divide by 36".
,ROUND UP.
Draperies with Repeats -
CORRECT|ANSWER
Divide window width by 3 to get stacking space in inches.
Add window width, stacking space and overlap (12").
Multiply that number by fullness factor.
Divide by fabric width (given).
ROUND UP. (Number of panels)
Multiply window height by 12 to get inches.
Plus header and hem.
Divide by repeat.
ROUND UP.
Times by repeat.
Times number of panels by modified cut length and divide by 36.
What type of plan is always needed to begin space planning in an existing building? -
CORRECT|ANSWER
Base plan
For most planning problems, the most efficient type of circulation system is what? -
CORRECT|ANSWER
double loaded corridor
What is needed to determine rentable floor area? -
CORRECT|ANSWER
net assignable area, efficiency factor, rentable-usable ratio
What is the net area or net assignable area of a building? -
CORRECT|ANSWER
, It is the space a client needs for their specific program functions like offices, work rooms or
conference rooms. It does not include the space needed for circulation, partitions or building
amenities, like restrooms. It is measured from the centerline of interior partitions of a space.
Anthropometrics -
CORRECT|ANSWER
concerned with measuring the size of the human body and developing dimensional ranges withing
certain percetages of a given population.
thermal comfort depends on -
CORRECT|ANSWER air movement, air temperature,
radiation, and humidity
Proxemics -
CORRECT|ANSWER deals with spacing between people and
organization of those spaces
In a plenum, how can a fire be prevented from spreading horizontally? -
CORRECT|ANSWER
fire-rated dividers
what construction should be used to enclose a 1 hr rated corridor? -
CORRECT|ANSWER
5/8" type x gyp on 3 5/8" metal studs
A compact filing system is an example of
A - dead load
B - dynamic load
C - lateral load
D - live load -
CORRECT|ANSWER
2026/2027 LATEST UPDATE | QUESTIONS AND VERIFIED ANSWERS
| GRADED A+
Carpet -
CORRECT|ANSWER
Length needed in stripes. (Ft)
Add together and divide by 3' to get yards.
Times by 4' for waste.
ROUND UP.
Carpet on Stairs -
CORRECT|ANSWER
Times number of risers by inches (height). Times
same number of treads by inches (depth)
Add those numbers together.
Add 1" per riser for nosing and wrapping.
Divide by 12 to get feet.
ROUND UP.
Take (ft) number and times by width of stairs.
Divide by 9 to get square yards.
Wallpaper (plain, residential) -
CORRECT|ANSWER
Calculate perimeter of room in feet.
Multiply by ceiling height.
Add 20% for waste.
Minus 15 sq. Ft per 1 door or 2 windows.
Divide by 36 to get how many single rolls.
ROUND UP.
Wallpaper (w/repeat, residential, half drop) -
,CORRECT|ANSWER
Divide height to be covered by repeat. (Minus any base or crown)
ROUND UP.
Take that number and times it by the repeat.
Convert inches to feet by dividing by 12.
Calculate the perimeter of the space in feet.
Times that by modified ceiling height (from before).
Add 20% for waste.
Minus windows and doors.
Divide by 36 for SR or 72 for DR.
Wallpaper 54" wide (commercial) -
CORRECT|ANSWER Calculate
perimeter of room.
Multiply perimeter by height.
Take no deductions for windows and doors unless o we 54".
Divide by 13.5 to get yards.
Times by 3 if linear feet are needed.
Times by $ if cost is needed.
Calculating Draperies (no pattern) -
CORRECT|ANSWER
Divide window width by 3 to get stacking space.
Add window width, stacking space, return and overlap together.
Return & Overlap = 12"
Multiple this number by fullness factor.
Divide by fabric width (54").
ROUND UP.
Determine cut length by multiplying height of window by 12 to get inches.
Add header and hem. (Given)
Take panel number times it by cut length number and divide by 36".
,ROUND UP.
Draperies with Repeats -
CORRECT|ANSWER
Divide window width by 3 to get stacking space in inches.
Add window width, stacking space and overlap (12").
Multiply that number by fullness factor.
Divide by fabric width (given).
ROUND UP. (Number of panels)
Multiply window height by 12 to get inches.
Plus header and hem.
Divide by repeat.
ROUND UP.
Times by repeat.
Times number of panels by modified cut length and divide by 36.
What type of plan is always needed to begin space planning in an existing building? -
CORRECT|ANSWER
Base plan
For most planning problems, the most efficient type of circulation system is what? -
CORRECT|ANSWER
double loaded corridor
What is needed to determine rentable floor area? -
CORRECT|ANSWER
net assignable area, efficiency factor, rentable-usable ratio
What is the net area or net assignable area of a building? -
CORRECT|ANSWER
, It is the space a client needs for their specific program functions like offices, work rooms or
conference rooms. It does not include the space needed for circulation, partitions or building
amenities, like restrooms. It is measured from the centerline of interior partitions of a space.
Anthropometrics -
CORRECT|ANSWER
concerned with measuring the size of the human body and developing dimensional ranges withing
certain percetages of a given population.
thermal comfort depends on -
CORRECT|ANSWER air movement, air temperature,
radiation, and humidity
Proxemics -
CORRECT|ANSWER deals with spacing between people and
organization of those spaces
In a plenum, how can a fire be prevented from spreading horizontally? -
CORRECT|ANSWER
fire-rated dividers
what construction should be used to enclose a 1 hr rated corridor? -
CORRECT|ANSWER
5/8" type x gyp on 3 5/8" metal studs
A compact filing system is an example of
A - dead load
B - dynamic load
C - lateral load
D - live load -
CORRECT|ANSWER
