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A sloping site can be very beautiful and have a great view. But its arrangement has many nuances and sometimes requires significant costs. Even a fence on a slope is not so easy to put up. After all, it is necessary to make sure that he does not “float” down the slope in a few years.
Fence with height difference: options
On a site with a slope, there are two ways to install fence posts:
- When each support is higher or lower than the previous one.
- Several posts have the same height, and the next group is higher or lower.
Both options are valid. How to do it is a matter of taste. There is no difference in reliability, but it is a little more difficult to implement the installation of each pillar at its own height.
In this option, the fence sections can be fixed both with steps and at an angle. Here there is already a difference. Let’s say a chain-link mesh can be pulled at an angle. You can nail a picket fence. But you can’t put sections or profiled sheets askew. Here, either cut the same corrugated board according to the required shape, or cut it into strips and collect from them. But cutting leaves open sections of metal, so they need to be painted over.
Calculation of “steps” when installing pillars
In order for the fence to look normal with steps, the height difference between groups of pillars or single supports should be the same. This is the main secret of attraction. And this difference must be calculated. For this you need to know:
- The length of the fence section on the slope.
- Height difference in this area.
- The length of the section or sheet if they are fixed.
Questions may arise only about the height difference. The easiest way to measure is to place posts of the same height in the corners of the site and measure the difference using a laser level. If there is no laser level, then you can use a bubble or hydro level.
Having all the data, we consider how many whole sheets / sections of the fence will be required to cover this section. To do this, divide the length of the section by the length of the section. Let us have a slope 18 meters long, with a height difference of 80 cm. The length of the section is 2 meters. We consider how many sheets will be needed: 18 / 1,5 = 12 pcs. So, we need 12 sheets 1,5 meters long.
We count the step for each leaf
If we “raise” each section, then it’s easy to calculate the height of the step: you need to divide the height difference over the entire section by the number of sheets.
In our example, there are 12 sheets, the slope on this section of the fence is 80 cm. We calculate the step height for each post: 80 cm / 12 sheets = 67 mm. So, each column will need to be raised by 67 mm. No one will fasten with such accuracy, approximately adhere to 7 cm.
Since the difference is small on a fairly long slope, too little height difference will not look very good. If we take into account the trouble with setting the difference in height, it is clear why this is done only in areas with a large slope. After all, otherwise, a group of sheets will have to be raised almost half the height of the section.
If you don’t like the “ladder”, having mounted the sheets in this way, their tops can be cut off by pulling the cord from edge to edge. Get a straight line. You can make a cut that repeats the outlines of the relief. A matter of taste.
If we are talking about corrugated board, then the cut must be painted over and closed with a special U-shaped profile.
How to align fence posts when installing on a slope? Same as on flat ground. Install the support pillars in the corners, check their position and height. At a certain height, tie a cord along which you will level the height of the pillars.
Height difference for pole groups
You can arrange sections/sheets into groups. The number of groups is arbitrary, as long as they are the same size. When choosing, consider aesthetics, but do not forget that the greater the height difference, the more materials will be required for installation.
For our example, we can make three or four groups. The fact is that 12 columns can be grouped by 3 or 4. It is permissible, of course, to make only two groups of 6 sheets, but there will be much more work. Therefore, they try to find a compromise – to make not too large spans of the same height, but not too small. Depending on how many groups there will be, the height of the “step” will change – more groups, less height.
- For 3 groups of 4 sheets: 80 cm / 3 groups = 26,7 см.
- For 4 groups of 3 sheets: 80 cm / 4 groups = 20 см.
How to decide? You have to look on the spot. All areas are different, different soils. Focus on the amount of work that you have to do to level the height of the pillars. In general, before making a fence on a slope, model it on paper. Draw the plan to scale on a piece of paper. With all the features of the relief. Cut out sections of the fence from the paper in the same scale and move them along the paper. It is clear that the reality will be different, but at least you will have options ready.
Pillars and/or foundation?
Conventionally, all fences can be divided into two types: with and without a foundation. What’s the best way to do it on a slope? Depends on what you want to achieve and how much money you are willing to spend.
Let’s say right away that a fence with a foundation on a steep slope must be made according to all the rules for the construction of retaining walls. There will be a lot of work and a lot of money will also be required. There are exceptions:
- a section of the fence at the highest point of the slope;
- along the fence there is a road and it is lower in level.
In all other cases, you will have to invest. In addition to the retaining wall, drainage will also be required. The thing is that in order for the fence on the slope not to “float”, it is necessary to collect all the water that flows towards it along the slope. And this can make a full-fledged drainage system. You will need, at a minimum, concreted grooves in front of the fence (better – trays), which will lead to drainage wells. And those should divert water down the slope or to the drainage field. This is a job description in a nutshell. Most likely, more land work will be required to redirect flows in the right direction. But there will be no water in the yard.
You can make a fence on poles / piles without a foundation. This is faster and cheaper, but the fence will not be a barrier to rain and water will flow through the yard. If there is a drainage system around the house, this is not a problem. It is important that it is designed to carry such volumes of water. If there is no drainage in the yard, you will have to do it. Otherwise, it’s just your house, sooner or later it will “crawl” down the slope.
How to make a fence foundation on a slope
If they decide to make a foundation for a fence, then they often choose a tape one. The technology is well known, but the slopes have their own nuances. It’s easier if you do it in steps. Start work from the bottom.
First, dig a trench, level it as far as possible with the “steps” that you plan to make. Make sure that the depth of the trench is not less than the permissible minimum. First of all, expose and concrete the pillars.
You assemble the formwork on a piece of the fence, which will have the same level, reinforce and fill it. For reinforcement, a corrugated steel bar is used – reinforcement with a diameter of 8-12 mm. They knit a double mesh, the optimal step is 200×200 mm. Reinforcement is required at the pole installation sites. Concrete for pouring the foundation of the fence is taken grade M 250. You can see an example of a project for a strip foundation for a fence on a slope in the picture below. The specified dimensions are a private option, designed for specific requirements and soils. In each case, adjustments must be made.
When the concrete gains 50% strength, remove the formwork, move it further, pouring the second step. If the deadlines are running out, make several formwork blocks.
It is possible to make both a prefabricated strip foundation and a rubble foundation on a slope. If you want to put a prefabricated tape, when calculating the “steps”, also consider the length of the block. Better (cheaper and easier) if they do not need to be cut.
The rubble foundation on an inclined section is placed in a similar way. Horizontal sections are verified using a building or laser level. Backfilling is carried out on the site of one “step. Then a vertical wall is erected to the height of the “step”, after which the laying “into the horizon” is carried out again until it is necessary to make the rise again.
Fence on a site with difficult terrain
What to do if the border passes through a difficult terrain: there are sharp drops both up and down. The first option is to level them. But this is a global task that requires serious construction equipment.
And keep in mind that if there is a “living” ravine through which a stream flows during rain, simply filling it up is not an option. The water will follow the same “route” and wash out your backfill. If you want to get rid of it, you need to intercept the precipitation in front of the ravine (with the help of drainage) and take it somewhere outside (into the same drainage ditch, for example). In this case, backfilling the ravine will be effective.
The second option is to make a fence on the foundation, which will repeat the relief. This can be realized both with the help of a rubble, stone base, and with the help of a concrete tape. It is very difficult to implement a prefabricated block foundation in such conditions, so it can be discarded.
If you pour a tape on a complex terrain, you will have to make your own formwork on each different section. It will have to be re-typed each time. You also need to start from the bottom. If this point is not on the edge, you can move in both directions. As for reinforcement: while the difference in height is not too big, we make a double grid (for example, 200×200 mm), as soon as we can make another tier, we add it.
Slope fence: what the regulations say
Building regulations also apply to the installation of fences – especially in areas with elevation changes. In order not to have problems with the authorities, it is better to do everything according to the requirements.
The rules indicate exactly how to build a fence on a slope in various situations. Each ratio of differences between the public area (sidewalk) and the private area is normalized. Everything is clear from the pictures. Here M is the height of the fence.
If the level of the private area is higher than the level of the sidewalk, the standard, in any case, requires the installation of a retaining wall. It will provide protection against slipping of the soil. Only the height of the fence differs.
In principle, if the private area is lower, nothing changes. A retaining wall is needed, and you will also build it, and also on your territory.