Footings, frost-heave , and related questions ???


I have some questions about under what circumstances footings are needed, and when needed, under what circumstances they must be below frost level.
I live in a mountain area when on occasion, the ground freezes to several feet of depth.
Here is my perception of "the rule" :
"For load-bearing structures, footings must be dug, and in areas where frost-heave is a problem, those footings must be below frost level."
Perhaps this is a correct statement, or perhaps it isn't quite complete, I am not sure. I suppose the main problem that I am having is determining what is a "load-bearing structure." I think some of the fine expertise that we have in this esteemed group can get me straight on this.
I have several small projects in mind. They are listed below, and I am wondering if in any (or all) of the instances, I would need footings and if so, would they need to be dug below frost line?
1. Small rock wall flower bed-- I plan to build a very small circle around a flower bed about 5 feet across. I will be using river rock, with an average size of 4 X 6 inches. The little wall or rock border will be about 12 inches high, and about 5-6 inches thick. I would not think the weight would be more than 50 lbs per foot of wall area.
2. Concrete pathway-- I plan to build some concrete pathways, about 3 feet wide and I suppose about 4-5 inches thick. It would seem that I could peg some forms to the ground, and pour the walkway with concrete. It would not appear to me that this would be a "load-bearing structure", but I am very inexperienced in these areas.
3. Retaining wall for flower bed. This is an area in a limited area of a flower bed adjacent to my house, where I need to replace a small area of a retaining wall, which will be built a sloping area. The entire wall will be about 8 feet in length, and (on the sloping ground) will be about 4 feet high on one end, and will slope to about 1 foot in height off the ground at the other end of the 8 feet. This wall will be built of 4 X 4 pressure treated beams, of .8 retention. There is a bit of "load" here, as the timbers themselves are pretty heavy. At the "high" end of the wall, I would have about 8 or 9 beams, but because of the slope, most of the beams will be less than 8 feet in length (wish I could draw a diagram).
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That's it on the projects. I have a number of questions:
1. Would any of these projects require footings ?
2. If any require footings, would they have to be below frost line?
3. Is rebar required in any of these projects?
4. Can the walkway be poured right on the ground, or should I start with a 3-4 inch bed of gravel ?
5. Does gravel itself help with the frost-heave problem ?
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Wow, that is a LOT of questions............ so, thanks for any constructive comments and advice !!
--James---
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Your rock wall may need a footing if it will be held together with mortar. Loose stones stacked on top of each other don't necessarily need a footing because since the rocks will be able to move independantly of each other.
Concrete pathways do not need footings.
Retaining walls made out of 4X4s don't need footings because each beam will move independently of each other. You really should do some research before building a retaining wall that size because there are a few things you'll need to know about them. Improper drainage at the top of a retaining wall will cause it to fail. Improperly anchored retaining walls will fail also.

Footings are always to bedrock or below the frost line (unless it is impractical to go below the frost line).

It is not required, but steel reinforcement greatly improves the strength of concrete. Sometimes they use a steel mesh under sidewalks and driveways, but rebar is better. If you've ever tried to bust up steel reinforced concrete and non-reinforced concrete, you'd be able to tell a big difference.

It is a good idea to put a layer of gravel, followed by a layer of sand, then your concrete. This will keep water away from the concrete. Many contractors just pour the concrete right on top of dirt. This is OK, but it's very likely you'll have spots that will crack and bust apart from frost heave. You also need expansion joints at regular intervals. The more problems you'll have with frost heave, the more expansion joints will be needed.

Yes. The gravel keeps water from directly underneath the concrete.
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I agree and second the suggestion to read about retaining walls and sidewalk jointing as well.
Tom Baker
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I would consider using concrete with embedded fiberglass fivers rather than rebar. In our area (Southwest Ohio) hardly any rebar reinforcements are used. If you order concrete, rather than mix it yourself, you can get eh fiberglass already mixed in. Consider it.
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I'm sorry, but you need to do a lot more research, and not in newsgroups, before you try any of these projects, or hire a contractor. Your local codes enforcement office would be a good place to start. They'll not only tell you what is required in your area, but they'll also tell you why. Many areas of the country now have to consider potential seismic damage as well as frost heave when planning structures, and that can govern how the footings are constructed for various projects. Retaining walls are NOT something for an amateur do it yourselfer to fool around with unless they completely understand soil drainage and proper construction techniques. Your life may depend on whether or not things are constructed properly. No joke.
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Naw, I reckon I can build a 12 inch high, 5 inch wide little flower garder border without getting my government involved.
And, I doubt that a retaining wall averaging 30 inches in height will endanger my life or that of my family. Furthermore, in the event that we should have an earthquake here, my little 24 inch sidewalk will be the least of my worries.
I do however thank you for your concerns regarding my safety.
But, I have received many helpful replies, which have addressed my questions of frost heave and footings.
--James--
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I'm sorry, but you need to do a lot more research, and not in newsgroups, before you try any of these projects, or hire a contractor. Your local codes enforcement office would be a good place to start. They'll not only tell you what is required in your area, but they'll also tell you why. Many areas of the country now have to consider potential seismic damage as well as frost heave when planning structures, and that can govern how the footings are constructed for various projects. Retaining walls are NOT something for an amateur do it yourselfer to fool around with unless they completely understand soil drainage and proper construction techniques. Your life may depend on whether or not things are constructed properly. No joke.
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