Math Problem

[Jim]

I know there are some pretty smart people on this forum, sure wish I was one of them. But alas, I live in NC and our abilities lay in the creation of liquid when proof is involved. Any chance there is a math wizard (or maybe engineer) available that can give me some help?

I'm trying to calculate the number of yards of concrete needed for an area with 4 different length sides. I believe this is called a quadrilateral, but I'm not sure. The slab needs to be 6" deep, when the sides are 36' X 15' X 24' X 30'.

Anyone?

 

[Rich W.]

I’m not a concrete guy, but I’ve done a few slabs and foundations. So….630 square feet, 315 cubic feet, 12 yards of mud (11.67 actually). That’s my guess. Also your perimeter should be 105’ so 9 12’ 2x6 for forms, some 1/2” plywood strips for gussets on the joints, a couple bundles of stakes, and all the rebar behind Hanks barn. Then four finishers should do it for tamp and screed, and at least one of them should be well skilled on the Fresno float and deep joints. Out here this slad would cost me around $3,000. Maybe $2,500 there depending on what finishers charge these days. If there’s any doubt about tailgating it, just spend the extra $500 for a pump. Much easier, less work, easier to pull up the rebar, brings another worker to the job, and the finished product will be better - more consistent and less time spent moving the mud around while its trying to set up on you. And on that, 6 sack will go off more quickly than 5, and adding a color will also speed it up. So if its coming from any distance go with a recipe that will take longer to set up. Lastly, hold the beer back until the job is done.

 

[FLSteve]

Try this and see if it works.

Area of a quadrilateral Calculator

Calculates the area and perimeter of a quadrilateral given four sides and two opposite angles.

keisan.casio.com

FLSteve

 

[Jim]

Try this and see if it works.

Area of a quadrilateral Calculator

Calculates the area and perimeter of a quadrilateral given four sides and two opposite angles.

keisan.casio.com

FLSteve

Thanks Steve, that one's very close to the calculator that I was using. Problem with the one I had was I didn't know how to figure the sum of two opposing angles.

 

[Jim]

I’m not a concrete guy, but I’ve done a few slabs and foundations. So….630 square feet, 315 cubic feet, 12 yards of mud (11.67 actually).

Wondering how you came up with the sq feet? I mean, if it were a rectangle, I wouldn't have any problem, but when the sides are all different, I have no clue.

Lastly, hold the beer back until the job is done.

Ah yes, this part I understand!

 

[Rich W.]

Wondering how you came up with the sq feet? I mean, if it were a rectangle, I wouldn't have any problem, but when the sides are all different, I have no clue.

I cheated and used the same calculator that FLSteve suggested. You could also just call your redi-mix yard and tell them what you have and they’ll tell you how many yards.

 

[Jim]

I cheated . . .

I should have sat behind you in math class.

 

[FLSteve]

Thanks Steve, that one's very close to the calculator that I was using. Problem with the one I had was I didn't know how to figure the sum of two opposing angles.

I would draw it (the slab) on a piece of paper "close to scale" and then you can measure the two (2) angles with a protractor and add them to know what number to plug into the formula. That will get you really close, I think.

FLSteve

 

[Jim]

Out here this slad would cost me around $3,000. Maybe $2,500 there depending on what finishers charge these days.

Boy, I sure wish we had your pricing out here. Material alone is over $3K. Best price I've gotten so far is $5,600. It's actually a pretty good size pad and will be a nice improvement for Site #1. The pad will be large enough to park a 45' Motor Home on and still have 15-20 feet of extra pad to put chairs, tables and Solo stoves on.

This pad will make leveling a non-issue and give everyone plenty of walking room so as to not drag leaves and other things into the coach.

 

[Rich W.]

Boy, I sure wish we had your pricing out here. Material alone is over $3K. Best price I've gotten so far is $5,600. It's actually a pretty good size pad and will be a nice improvement for Site #1. The pad will be large enough to park a 45' Motor Home on and still have 15-20 feet of extra pad to put chairs, tables and Solo stoves on.

This pad will make leveling a non-issue and give everyone plenty of walking room so as to not drag leaves and other things into the coach.

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I may be a bit behind the times on this. Last I checked, concrete here was about $110/yd, and finishers get around $300/day (for about four hours of actual work). But I also do site prep, gravel and forms myself. Does your price include a contractor? Nothing against them, but it always seems to about double the price. My last slab was around 1,500sq/ft and cost me a around $5,500.

Beautiful park by the way and it just seems to keep getting better. It’s on my list of stops next time I’m out you way.

Coach parking at home (note there’s room for about 10’ of extra coach):