About Corrugated Metal Fence Calculation
This calculator estimates the main materials for a corrugated sheet metal fence based on the specified fence length, post spacing, fence height, and foundation parameters. It is suitable for preliminary estimation of the number of posts, rails, corrugated sheets, and concrete volume before purchasing materials and starting installation.
The calculation is intended for linear fences with repeating spans. The calculator helps quickly obtain geometry and material quantities when comparing several options for post spacing, fence height, or foundation type.
Guidelines and recommendations
General calculation principle
Calculation model. The calculator treats the fence as a sequence of spans along the total length L in mm. The calculation is based on the fence length, post spacing S in mm, fence height H in mm, bottom ground clearance Z2 in mm, top offset Z1 in mm, and post embedment depth G1 in mm.
Span division logic. First, the total length is divided by the selected post spacing. If the length L is divisible by the spacing S, all spans are equal. If it is not divisible, the calculator keeps the main spacing for the standard spans and makes the last span shorter by the remaining length.
n = L / S
Meaning of the result. Based on this model, the number of spans is determined, after which the rail lengths, number of rail rows, post lengths, and corrugated sheet area are calculated. This approach is convenient for material takeoff and preliminary fence layout planning on site.
How the number of posts and spans is determined
Number of spans. The basis is the ratio of the fence length to the post spacing. With exact division, the result is a series of equal spans. If there is a remainder, the last span is taken as shorter, which makes it possible to keep the specified total fence length without redistributing all axes.
Number of posts. The final value is usually taken as the number of spans plus one end post. In practice, this means that for equal spans there is always one more post than spans.
Nposts = Nspans + 1
Practical guideline. For corrugated sheet metal fences, post spacing of 2000-3000 mm is often used. As the spacing increases, the number of posts and foundations decreases, but the rail length per span and the sensitivity of the fence to wind load both increase.
How rails are calculated
Rail length for one span. If the rail is installed between the posts, its calculation length is taken as equal to the spacing S. If the rail is installed flush with the post, the post width is subtracted from the spacing because the usable length between the outer faces becomes smaller.
Lrail = S
Lrail = S - bpost
Number of rail rows. The calculator uses a simple rule based on fence height. For fence heights up to and including 1700 mm, 2 rail rows are used. For heights above 1700 mm, 3 rail rows are used.
H ≤ 1700 mm - 2 rows
H > 1700 mm - 3 rows
Total rail length. After that, the length of one rail is multiplied by the number of rows. This gives the total rail length for one span or for the entire fence, depending on the selected purchasing approach.
Lrails,total = Lrail × Nrows × Nspans
Practical guideline. For fences around 1.5-1.7 m high, 2 rail rows are often used. For heights of 1.8-2.5 m, 3 rows are a common choice because they reduce corrugated sheet deflection and improve panel stiffness.
How post length and concrete are calculated
Length of one post. The calculator adds the fence height H and the embedment depth G1, then subtracts the top offset Z1. This gives the working post length for the above-ground and below-ground parts, taking into account that the top of the post may extend above the sheet by less than the full fence height.
Lpost = H + G1 - Z1
Total post length. The total post requirement is determined by multiplying the length of one post by the number of posts. This is useful for selecting standard tube lengths and estimating the number of cuts.
Lposts,total = Lpost × Nposts
Concrete volume. If a concrete foundation option for the posts is included, the volume is calculated as the product of the dimensions of one concrete part H1, B1, and A1 in mm, multiplied by the number of posts. Conversion to m3 is performed by dividing by 1 000 000 000.
Vconcrete = Nposts × H1 × B1 × A1 / 1 000 000 000
Practical guideline. For lightweight corrugated sheet metal fences, post embedment depths of about 700-1200 mm are often used. The exact value depends on fence height, wind zone, soil type, and frost depth.
How the corrugated sheet is calculated
Effective sheet height. The calculator determines the corrugated sheet height as the difference between the total fence height H and the bottom ground clearance Z2. This means that only the actually covered part of the span is included in the cladding area.
Hsheet = H - Z2
Total corrugated sheet area. After that, the effective sheet height is multiplied by the fence length L. Conversion from mm2 to m2 is performed by dividing by 1 000 000.
Asheet = Hsheet × L / 1 000 000
Meaning of the result. This is the geometric fence area without longitudinal sheet overlap, width cutting losses, or installation allowance. For material purchasing, it is usually useful to include additional reserve for trimming, joints, and accidental damage during installation.
How to choose the final values in practice
Choosing post spacing. The calculator does not optimize spacing automatically, but calculates strictly according to the entered value. For that reason, the final choice is usually made by comparing several options, for example 2000 mm, 2500 mm, and 3000 mm, to see the balance between the number of posts, rail length, and concrete consumption.
Choosing height and number of rails. If two similar height options are being considered, the final choice is usually based on the more demanding case. This is especially important for exposed locations, open terrain, and high solid fences, where increasing the height has a clear effect on wind action.
Normative framework. For this type of preliminary calculation, common reference documents include EN 1990 Eurocode - Basis of structural design, EN 1991-1-4 Eurocode 1 - Actions on structures - Wind actions, EN 1993-1-3 Eurocode 3 - Design of steel structures - Cold-formed members and sheeting, EN 1993-1-8 Eurocode 3 - Design of steel structures - Joints, and EN 1090-2 Execution of steel structures. This calculator does not replace design verification under these standards, but provides the initial geometry and material quantities that can then be used for structural checking.
FAQs
Does the calculator account for corrugated sheet overlap?
No, the corrugated sheet area is calculated from the pure fence geometry as the product of effective height and total fence length. When purchasing corrugated sheets, it is usually advisable to add reserve for side overlap, trimming, and installation losses.
Why does the number of rails change when the fence height increases?
A simple rule is used here: up to and including 1700 mm, 2 rails are used, and above 1700 mm, 3 rails are used. This is a typical practical guideline for a preliminary corrugated sheet metal fence calculation, because it increases span stiffness as height grows.
What does bottom ground clearance mean?
This is the distance Z2 between the ground and the lower edge of the corrugated sheet. It is subtracted from the total fence height, so it directly reduces the calculated sheet height and cladding area.
Is this calculation suitable for selecting post section size and checking wind resistance?
No, this calculator mainly calculates geometry and material quantities for the fence. To verify posts, rails, fixings, and foundations for strength and stability, wind load, soil properties, and Eurocode requirements must be considered separately.
Why is it useful to calculate several post spacing options?
Because post spacing affects several results at the same time: the number of posts, concrete volume, rail length, and span layout. Comparing several spacing options helps select a more rational corrugated sheet metal fence solution in terms of cost and stiffness.