square feet to cubic yards

i have a commercial lot that is 14420 sq. ft. the concrete slab will be 3 1/2 feet thick. i have footings that measure 1 1/2 ft by 1 1/2 feet by 1 feet stretching 778 feet i have 30 piers to concrete at 1 1/4 feet by 1 1/4 feet by 2 feet. how many cubic yards of concrete will i need for the job?

i have a commercial lot that is 14420 sq. ft. the concrete slab will be 3 1/2 feet thick. i have footings that measure 1 1/2 ft by 1 1/2 feet by 1 feet stretching 778 feet i have 30 piers to concrete at 1 1/4 feet by 1 1/4 feet by 2 feet. how many cubic yards of concrete will i need for the job?

[JohnS]

Originally Posted by robert duzant

i have a commercial lot that is 14420 sq. ft. the concrete slab will be 3 1/2 feet thick. i have footings that measure 1 1/2 ft by 1 1/2 feet by 1 feet stretching 778 feet i have 30 piers to concrete at 1 1/4 feet by 1 1/4 feet by 2 feet. how many cubic yards of concrete will i need for the job?

1) Do you mean 3.5 inches, not feet? 3.5 feet seems way too thick and if you needed that thickness, the footings and piers are inadequate.

2) You seem to have four dimensions for the footings, I've assumed 1.5' x 1.5' x 778'

Slab 14420 ft² x 3.5 in x 1 ft/12 in x 1 yd³/27 ft³ = 155.77 yd³
Footings 1.5' x 1.5' x 778' x 1 yd³/27 ft³ = 64.83 yd³
Piers 30 x 1.25' x1.25' x 2' x 1yd³/27 ft³ = 3.47 yd³
Grand total 224.1 yd³

There is no allowance for the concrete displaced by rebar. Actual will be slightly less.

400 sq. ft. 6" deep
- 400 sq. ft. @ 1 foot deep is 400 cubic yards ~ (10'x40'X1')
- 6" deep is half of 1' therefore in your case you only have half the cubic feet as 1' deep
~ 10'x40' x '0.5' = 200 cubic feet
- now to convert cubic feet to cubic yards you must first know a few things about a cubic yard. a cubic yard is NOT 3 feet wide by 1 foot deep... instead this would be 3 cubic ft.
- a cubic yard is 3 feet wide by 3 feet deep.. this means there's 3 rows of 3 squares stacked into 3... thus looking like this in a mathematical equation ~ 3x3x3
- the answer is 27 cubic feet. Now we know that 27 cubic feet makes up 1 cubic yard.
- now we know what we need to divide our cubic feet by to get cubic yards
~ 200/27 = 7.407 cubic yards

-- A good rule of thumb i use for concrete is the square footage of the pad divided by 75.
~ this is because at 4" deep 1 cubic yard goes about 80 sq. ft. and 4" deep is what most common flat pours are. allowing for some waste i divide by 75 instead of 80. so in your scenario.. your wanting 6" deep instead of 4" deep. that is ok though, we have enough information to just use a proportion.
first off starting from beginning ~ 400 sq. ft. divided by 75 = 5.333 cubic yards
~ this answer is providing the slab is 4" thick.. you know 2" more (6") is 50% of 4
thus 4 times 1.5 = 6 so you want 5.333 times 1.5 = 8 cubic yards
--you'll notice this answer is a little over a half a yard more than our first calculation. but a half a yard to a yard over is a pretty good waste allowance. if you calculate the first way- the answer is exact so you have to add for waste. using my 75 sq. ft. rule - your waste is allowed for happy building and god bless

I need 734 sq,ft.of mulch at a 3 inch depth. How many cubic yards do I need, if I buy it by the cubic yard.
If I buy it by the bag that is 2 cubic ft. how many bags would I need to purchase?

[Mrs X]

Originally Posted by Unregistered

I need 734 sq,ft.of mulch at a 3 inch depth. How many cubic yards do I need, if I buy it by the cubic yard.
If I buy it by the bag that is 2 cubic ft. how many bags would I need to purchase?

Sounds like a home work question.

3" is 1/4 of a foot (0.25).

To work out cubic feet, multiply the area in square feet by the thickness in feet. (Then it is easy to work out how many bags you need).

There are 27 cubic feet in cubic yard.

You are welcome to post back here if you would like your answers checked.

If I need 40 yards of carpet and the carpet cost .64c a sq ft. How much is the carpet? I know this is simple and i'm just overthinking. lol thank you

[JohnS]

Originally Posted by Unregistered

If I need 40 yards of carpet and the carpet cost .64c a sq ft. How much is the carpet? I know this is simple and i'm just overthinking. lol thank you

1 yd² = 9 ft² so price is $5.76 yd²

Divide by 98 (to be exact divide by108)

Originally Posted by Robert Fogt

It depends on the thickness.

I assume this is something like sand or gravel or soil. Just need to know how thick you plan on spreading it.

75' x 100' 2' thick