Question

a painter is painting a ceiling of a sqaure room the walls are 15 feet long. if a gallon of paint covers 45 square feet how many gallons of paint will be needed to cover the entire ceiling

Answer 1

@MismycatMIn ??

Answer 2

gallonsquare feet
Other websites say a gallon will cover 400-450 square feet of smooth surface. If you've got a rough textured surface or surfaces which need 2 coats of paint, a gallon will cover about 200 square feet.


The above answer may be a general rule of thumb. However so many people on here are passing themselves off as professionals with out actually knowing or at least explaining the real answer to this question.

Technically this question can not be answered with out more information. First and foremost the % of solids by volume must be known. Ultimately that number gives you actual amount of product that will be left behind on your wall when the paint dries.

Texture simply adds to the area of the surface your are painting. The smoother a wall the less area you have to paint. If the wall is textured the height of the peaks and the lows of the valleys increase the area within the same square foot.

Example: If you imagine two cities joined by a flat road 100km apart and you are driving 100km/hr it is going to take 1 hour to drive from one city to the other. Now imagine the same two cities joined by a road but this time the road has a mountain between the cities. The horizontal distance is still 100km apart but now you must go up the mountain then back down the mountain to reach your destination. Obviously if driving at 100km/hr you are going to take longer to make this trip. The reason it takes longer is because it is farther going up the mountain then back down to reach your destination. A rough wall surface acts like a mountain !

Now to answer the above question lets assume that you have 100% solids by volume paint. That gallon of paint is going to spread out at 1604sq' at 1 mil thick. Don't ask how I know this but it is a fact. 100% solids by volume paint no matter the type will always spread at this number (1604sq' per mil). Now if you have a substrate with 400sq' to paint and use 100% solids paint then it is going to take :

400sq' / 1604sq' per mil = .249 gal at 1 mil thick

Now if you need the paint to be 4 mil thick to provide the coverage and protection then the math is as follows:

1604sq' per mil per gal / 4mil required = 401sq' per gal

400sq' / 401 sq per gal at 4 mil thick = .9975 gals is required

Now lets say that your paint is only 50% solids by volume then the math would be as follows:

1604sq' per gal at 1 mil x 50% solids per gal = 802 sq' at 1 mil

802 sq' per mil per gal / 4mil required = 200.5 sq' per gal

400sq' / 200.5 sq' per gal at 4 mil thick = 1.995 gals is required

Now all the above calculations are assuming 100% transfer of product (no waste) as that is unlikely to ever take place you must accommodate for waste. use a percentage of expected wast and apply that to the figure you end up with to increase the amount required.

Now this calculation system will work for any type of paint at any % solids by volume. But without knowing the % solids by volume of the product you are using any number that you come up with will simply be a guess.

So now you know !

Use the information wisely ! :-)

Answer 3

so the answer is??? @MismycatMIn im sorry its just i need to hurry :/ if you dont know it thats fine :)

Answer 4

1.995 gals is required

Answer 5

here ill show you the possible answers @MismycatMIn

Answer 6

4, 5 , 6 , 3