Newbie...Can I dig my own footings?

[Green4310TLB]

I had a big old backhoe a few years ago (before I got the compact) and did the footer for my house. Works best if the site is already level, but you can use a transit to figure out how deep you need to be in each corner. Put a steel rod in the ground at the exact corner of the wall and use spray paint to paint over the string. (be sure you have already measured corner to corner and have the wall line square and straight.) This gives you a straight line to reference when digging. Remove the string and steel rod. If your block is 10", dig the trench 4-6" wider then the line to the outside. (Assuming you have a 24" bucket.) It does not need to be exact, but if you get off your line much your going to be dumping a lot of conrete and money in when you don't need to. Also, don't forget to ask around, you might find someone (a buddy or coworker) who has done this and can get you started. Also in PA we go at least 36" deep, sometimes deeper to get below the frost line. Sounds like you would need to as well.

 

[beeforty]

As Green431tlb said,make sure your diagaonal measurements are equal or you will be cursing when you get to the roof. I had to build on someone else's slab that was 11" racked Also before you pull your corner stakes, put extra stakes out side of your digging area so that you can pull string across the corner points. Commonly what builders call batter boards, you will need to find the corners after trenches and any holes are dug. You string lines back and forth so that you can drop a plumb bob where any critical point is going to be in your concrete and helps keep your forms straight.
here is a quick link for basic idea:
batter board: Definition from Answers.com

 

[Bigturk]

Nice looking property. Your garage plans are not complicated but I think your building site is. I don't think a floating slab(monolithic pour) would be the best solution to your sloped lot. Building one wall of your garage into the bank is what I would think about doing. This footing and wall would help support the bank from erroding and support your garage. This would let you maximize your space by tucking your garage into the bank. The wall that supports the bank would need to be thicker to support the weight of the bank. A popular product used for frost walls in Eastern Canada is ICF or insulated concrete form. It is easy to work with and becomes your forms for the concrete. They remain in place after the concrete is poured. The wall that is holding back the bank could have an 8 inch center and the rest of the frost wall could be 6 inch. Rebar is used to strengthen the concrete. The concrete wall built into the bank could be 4 to 6 feet high inside your garage where the other frost walls are just above grade level. I hope this make sense.

If you could get away with a floating slab, I would suggest to go for it by doing the work yourself.

I think your site is challengung and if it was me, I would hire a professional.

But, you know what they say about opinions - everbodys got one.

Good luck. I plan to build a 24 x 30 garage this summer.:thumbsup: