Figuring your needed amount of concrete for a project is the easy part. Forming, pouring, and finishing the concrete is the hard part. Most slabs are poured at 4 inches thick. You take the length of the formed area and multiply that by the width. Take that total and multiply it by 0.33 for a 4 inch thick slab then divide that total by 27 for the total yards of concrete you will need to pour the slab. Here is an example calculation for a 10 X 12 slab at 4 inches thick.
10 x 12 = 120 x 0.33 = 39.6 divided by 27 = 1.46 yards of concrete.
W x L x 0.33 / 27 = Total yards of concrete needed at 4 inches thick.
W x L x 0.49 / 27 = Total yards of concrete needed at 6 inches thick.
W x L x 0.66 / 27 = Total yards of concrete needed at 8 inches thick.
*Note- It is always a good idea to add just a little to the total amount of concrete that you figure simply because it is better to have a little extra than to come up short.
A 4-way switch is used when you need more than two switching locations on a lighting circuit. You can add as many 4-way switches as you want in between two 3-way switches. Basically all you need to make it work is to have all your switch boxes tied together with 3-conductor romex.
Here is one way to wire it and there are many ways. You will, of course , need a power feed into one end of the 3-way. Then you would run a 3-conductor with ground from that 3-way to the first 4-way location. Then take another 3-conductor romex to the next 4-way and if there isn’t a next 4-way then you just take that 3-conductor to the other end of the 3-way. In this 3-way box you will need a 2-conductor switch leg up to your light fixture and that is all the wiring you will need to make it happen.
At one end you have a black and white power feed and a black, white, and red 3-conductor. The black power feed hooks to the common lug on the 3-way switch. The two whites tie together with a wire nut and push back in the box. The remaining black and red in the 3-conductor will tie to the two remaining traveler lugs on the 3-way switch.
The other end 3-way wires the same way except the black from the 2-conductor will still tie to the common lug on the 3-way switch but it will be going to the light fixture instead of being a hot feed like the other end did. The two whites tie together and the remaining black and red go to the traveler lugs on the 3-way switch.
Now for the 4-way switch in the middle you will have two 3-conductor cables. One from each end on the 3-way switches. The two whites will again tie together with a wire nut and push back in the box. On the 4-way switch you will notice 4 lugs plus the green grounding screw. The two top lugs will be a different color than the two bottom lugs on the switch. Just make sure that the black and the red from the same romex ties to the same two colored lugs on the top of the switch and the other black and red from the same romex ties to the two same colored lugs on the bottom of the 4-way switch. That should give you two reds on one side and two blacks on the other side of the switch.
The 4-way switch makes contact in either a vertical pattern or a crossing pattern like an X. So depending on which way the switch is flipped, it would make contact like this ll or like this X. See the wiring diagram below for a visual of how a 4-way works.
