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harley dahnke
12-23-2005, 07:29 AM
How much surface 4" thick will a 60# bag of pre-mix concrete cover?

Robert Fogt
12-23-2005, 04:34 PM
According to Reade, portland cement weighs 94 pounds/cubic foot

60 pounds / 94 pounds/cubic foot = 0.6383 cubic foot

Now we have the volume and the thickness, so we can calculate the area. First have to convert 4 inches to feet.

0.6383 cubic foot / (4 inches / 12) foot = 1.9149 square feet

It will cover about 2 square feet that is 4 inches thick. Assuming a density of 94 pounds/cubic foot

Unregistered
10-13-2006, 07:46 PM
How much surface 4" thick will a 60# bag of pre-mix concrete cover?
I have an area 5'x4' 4' thick how many bags of concrete 40 lb do I need.

Robert Fogt
10-13-2006, 11:50 PM
Try this calculator here:
http://www.decks.com/calculators/concrete.aspx

Though it only lists how many 60 pound or 80 pound bags you need. But you can take the 80 pound bag number and divide by 2.

Unregistered
12-13-2006, 01:25 PM
I believe they are talking about "bags" of pre mixed conrete which come in 60 # bags as opposed to "sacks" of portand cement which weigh more.

Unregistered
01-05-2007, 09:23 AM
How much surface 4" thick will a 60# bag of pre-mix concrete cover?

The Instructions on the pre mix concrete bags say a #60lb bag will do 1 square foot, 4"thick.

Unregistered
06-08-2007, 11:36 AM
The information was great thanks

Unregistered
06-24-2007, 08:28 AM
How much surface 4" thick will a 80# bag of pre-mix concrete cover?

Unregistered
07-13-2007, 06:59 AM
How much surface 4" thick will a 60# bag of pre-mix concrete cover?
how many bags will be need to complete a 20' X 3'6"x4"

Unregistered
08-05-2007, 02:27 PM
how many bags of 80# ready mix I need for a 9'x9'x2"thick area?

A guy
08-08-2007, 01:32 PM
Look up a few posts to the calculator link. Just use the Square Footing to calculate whether it's 6"x12"x4" or 30'x20'x4". Although as you get into the really big areas your error will increase, because the amount of water you use in your mix will likely vary from what they used to get their data.

Unregistered
03-30-2009, 04:21 PM
how many bags of 60# or 80# do i need for an area of 13'x9'. 4" thick?

JohnS
03-30-2009, 05:57 PM
how many bags of 60# or 80# do i need for an area of 13'x9'. 4" thick?
4" = 1/3 ft, so you need 39 ft³
An 80 lb bag yields 0.6 ft³, so 65 bags.

Ready Mix
04-15-2009, 12:43 PM
how many bags of 60# ready mix concrete would i be needing if i want 5'x5' area that is 2" thick? I'm new to this, and have read a quick guide on what portland concrete is on a concrete guide, but I still do not know much about the quantities I should be using. thanks!

____________________________________

larry

JohnS
04-15-2009, 01:43 PM
how many bags of 60# ready mix concrete would i be needing if i want 5'x5' area that is 2" thick? I'm new to this, and have read a quick guide on what portland concrete is on a concrete guide, but I still do not know much about the quantities I should be using. thanks!

____________________________________

larry
2" = 2/12 ft
5' x5' x (2/12) ft x 1 bag/0.6 ft³ = 6.94 bags (use 7)
assuming 80 lb bag yields 0.6 ft³

Dirtman
04-15-2009, 06:16 PM
how many bags of 60# ready mix concrete would i be needing if i want 5'x5' area that is 2" thick? I'm new to this, and have read a quick guide on what portland concrete is on a concrete guide, but I still do not know much about the quantities I should be using. thanks!

____________________________________

larry

John's correct for an 80 lb bag of Sacrete.

Approximate yield for a 60 lb bag of Sacrete is 0.45 ft3. 4.17 ft3/0.45 ft3 = 9.26 bags (10 minimum).

Approximate yield for a 40 lb bag of Sacrete is 0.30 ft3. 4.17 ft3/0.30 ft3 = 13.89 bags (14 minimum).

I don't know what you'll be placing on this small slab but chances are 2" inches of concrete is going to crack. The minimum thickness should be 3" IMHO.

Jason Patterson
10-21-2009, 11:13 AM
In general, if a 60# bag can cover 1 square foot 4 inches deep, then the following will work to determine the number of bags you need:

Step 1:
Figure out the volume of concrete you need in cubic feet. Use feet for units in all numbers.

Volume = Length x Width x Depth x Number of Objects
(For rectangular pads of uniform thickness)

Volume = 3.14 x Radius x Radius x Depth
(For round pads of uniform thickness)

Ex: I want to pour two 4'x10'x9" slabs. What is the volume?
V = 4 x 10 x (9/12) x 2 = 60 cubic feet

Step 2:
Figure out how many bags that is based on the bag size you want. Since a 60# bag can fill 1/3 cu ft, it takes 180# to fill 1 cu ft.

Number of Bags = Volume x 180 / (Bag Size)

Ex: Continuing on, if I wanted to use 40# bags for my slabs, how many would I need?
N = 60 x 180 / 40 = 270 bags