Average Cost Per Sqft

Volume of sphere is V=(4/3)3.1415Radius Cubed of sphere.
So, assuming a 14' dome as made at workshops, 6" or 1/2 foot thick walls, a true half sphere (dome) then calculate the volume of 14' sphere then subtract the thickness and calculate the volume again and subtract from the first. Finally, divide by 2 and this is the volume of material.
So..
Diameter = 14' feet
Radius=7
Thickness=.5
(4/3) x 3.1415 x 7=1.333333333 x 3.1415 x 7 x 7 x 7=1,437 cubic feetDo again with Radius of 6.5
(4/3)x3.1415x(6.5x6.5x6.5)=1150 cubic feetSubtract the two and dived sphere in half.
14371150=287/2=144 cubic feet.Using the prices above of $12 for 7 cubic feet or say $1.72 per cubic foot the dome would cost $251. This doesn't include the foundation.. So, a 14" foot dome has (pie*Radius squared) 153.9 square feet which is $1.63 square foot in for a perfect half sphere dome that is 14 feet in diameter. Again, not counting the foundation...
I made a Google spreadsheet to calculate cost. Not sure if it's works with only viewing privilege, but your welcome to try it...

Can someone help me calculate 120sq/ft dome please? I am having trouble understanding the calcs above...Thanks:)

@HandyDan tHANKS FOR THE INFO!

Here is another aircrete dome calculator google spreadsheet. Please don't ask for permission to edit. Please do make a copy for yourself and then tweak it to your heart's content!

I have a cost an material estimator setup you are welcome to use. Just select your numbers in the green fields and it will show you the cost as well as the amount of materials to order.

A 94 pound bag of cement generally yields 45 gallons of aircrete which equals 6 cubic feet. 6 cubic feet of aircrete would make a 6'x3'x4" slab or a 6'x4'x3" slab that you could cut into blocks.

@handydan Thanks for this very useful tool in calculating material and cost!

@ignaciodhome I'm glad you found it useful.

Is there a metric calculator available? These American measuring units are very confusing.

@Kwagga 42 KG of cement makes .17 cubic meter of AirCrete.
There is some data required to make a metric version:
What price & volume of foaming agent is used there.
Weight & price of Portland cement bags.
Dimension and cost of soft poly reinforcing fabric.

@IgnacioDHOME
120 Square feet done
(120/3.1428)Square Root=radius 6.18. A 12.36 foot domeThe cost for foundation and done would be $835 ish dollars if you make it 12 foot at 4.5 inch thick walls.
44 bags of cement
3 gallons of Drexel foam agent
1 roll of soft polyester.

@Kwagga I just use online conversion calculators. Just Google "inch to meter" or what ever units are involved.

@Zander Thanks man! Yours seems better than mine (experienced) so I am going to use yours.

@HandyDan said in Average Cost Per Sqft:
3 gallons of Dresses foam agent
Can you pleas describe or provide a link to this "Dresses foam agent"? I can't find it.

@anthonydjones That was my automatic spell checker.. it's Drexel FM 160

@anthonydjones said in Average Cost Per Sqft:
@HandyDan said in Average Cost Per Sqft:
3 gallons of Dresses foam agent
Can you pleas describe or provide a link to this "Dresses foam agent"? I can't find it.
There are also other almost identical foaming agents available at local farm stores.
They are used for "row marking" where the tractor squirts droplets of foam so they can mark where they went.