A square is 100 square feet and the tabulation method we use.  This is primarily due to the spread rate for our product. Two coats of paint is an equivalent thickness of a page in the phone book.  Two coats of Liquid Ceramic is as thick as the phone book cover (12 mils). We use one gallon of Liquid Ceramic for every one square of your home, on an average.  Our spread rate is 175-225 SF per gallon.  Using an average of 200 SF per gallon per coat, two coats requires one gallon per square.  Windows use a percentage of a gallon, which is why we ask you to send us your numbers, we will plug those into our spreadsheet and crank out the number pretty fast.  

We measure all walls (taking out window and door areas) and we measure all soffit and fascia.  We count each window and door that requires coating. 

A note on doors.  Liquid Ceramic lasts a long time because it stays flexible a long time...so far, we think it may be forever, we know it stays flexible for up to 40 years.  This allows it to move with your home and not crack.  To achieve this, it had to be engineered with a longer initial cure time.  Liquid Ceramic is dry to the touch in an hour, typically.  However, it does not get to 95% of its total hardness for up to 120 days.   As a result, it may not be suitable for some doors. For that reason, we use a High Performance paint for front doors and some high use entries.  Other doors we treat so that they do not stick and this generally works well.