Cladding Fixings Calculator

Inputs

Panel width (m)

Panel height (m)

Weight input mode

Use areal weight for uniform panels.

Areal weight (kg/m²)

Total panel mass (kg)

Design wind pressure (kPa)

Positive pressure; used for worst magnitude check.

Design wind suction (kPa)

Suction typically governs fastener tension.

Horizontal spacing (mm)

Vertical spacing (mm)

Allowable tensile (N)

Use tested or manufacturer values.

Allowable shear (N)

Load factor (γf)

Applies to wind and weight.

Material factor (γm)

Divides the stated capacities.

Edge load factor

Amplifies edge fixings relative to field.

Results appear above after submission.

Example data table

Parameter	Example value	Unit	Notes
Panel width	1.20	m	Typical façade module
Panel height	2.40	m	Story-height cladding
Areal weight	18	kg/m²	Includes subframe allowance
Wind suction	1.80	kPa	Often governs tension
Spacing H × V	300 × 400	mm	Initial grid assumption
Allowable tensile	1500	N	Based on substrate testing
Allowable shear	1200	N	Consider bracket behavior

Formula used

Panel area: A = W × H

Governing pressure: p = max(p_pressure, p_suction)

Wind load: F_w = p × 1000 × A

Self-weight: W_s = m × g, where g = 9.81 m/s²

Design loads: F_w,d = γ_fF_w, and W_d = γ_fW_s

Fixing grid count: n = (⌊W(mm)/s_h⌋+1) × (⌊H(mm)/s_v⌋+1), minimum 2×2

Weighted distribution: n_w = n_edgek_edge + n_fieldk_field

Tension per fixing: T_edge = (F_w,d/n_wedge, T_field = (F_w,d/n_wfield

Shear per fixing: V = W_d/n

Design resistances: R_t = R_t,allow/γ_m, R_v = R_v,allow/γ_m

This tool uses simplified load sharing. Corner/edge zones can be governed by project-specific code coefficients.

How to use this calculator

Enter panel width and height in meters.
Select weight mode and provide areal weight or total mass.
Enter design wind pressure and suction for the panel zone.
Set your intended horizontal and vertical fixing spacing.
Input fastener allowable tensile and shear capacities.
Adjust γ_f, γ_m, and edge factor to match your basis.
Press Calculate and review utilization and suggested spacing.
Export a CSV or PDF report for design records.

Professional guide to cladding fixings

1) Why fixing design matters

Cladding panels face repeated wind suction, pressure reversals, thermal movement, and dead load from self-weight. A reliable fixing layout limits panel deflection, protects the support system, and reduces risks like pull-out, bearing damage, and vibration loosening. Early checks help align panel sizes, bracket locations, and fastener selections before site installation begins.

2) Loads and demand paths

Wind usually governs tensile demand because suction tries to lift panels away from the substrate. Self-weight typically contributes to shear demand, especially at brackets or rails. This calculator applies a load factor to develop design actions, then distributes the wind demand across a fixing grid with an edge amplification factor to reflect higher edge-zone demand.

3) Fixing grid logic

For practical layout, the fixing count is based on panel dimensions and spacing in both directions. A minimum 2×2 pattern is enforced to avoid unconservative single-line support. The tool also separates edge and field fixings so you can see how perimeter demand affects capacity checks and recommended spacing.

4) Capacity inputs

Fastener tensile and shear capacities should come from manufacturer data, project testing, and substrate-specific evaluations. Apply appropriate material factors when converting stated capacities to design resistances. If a connection relies on brackets, rails, or anchors, ensure the weakest component is represented by your inputs.

5) Example data set

Example: Panel 1.20 m × 2.40 m (A = 2.88 m²), areal weight 18 kg/m², wind suction 1.80 kPa, spacing 300 mm × 400 mm, tensile capacity 1500 N, shear capacity 1200 N, γf = 1.50, γm = 1.25, edge factor = 1.50. Run the calculator to see grid counts, edge tension demand, shear per fixing, and utilization ratios.

6) Interpreting results

Utilization expresses demand divided by design resistance. Values under 100% indicate the simplified check is satisfied for that mode. If the edge tension utilization is high, reduce spacing, increase fastener capacity, or review zoning pressures. If shear utilization is high, check dead load assumptions and support details.

7) Practical detailing tips

Confirm edge distances, embedment depth, corrosion protection, and compatibility with cladding materials. Consider movement joints and thermal breaks in subframes. Maintain consistent installation torque and quality control. For high-rise façades, corner zones and local pressure coefficients may require more conservative assumptions than a single uniform pressure.

8) Limitations and good practice

This calculator provides a quick, transparent screening check for fixing quantity and spacing. Final design should follow your governing façade standards, account for multiple load cases, and include substrate pull-out testing where required. Always document inputs, assumptions, and verification steps for project records.

FAQs

1) Which wind value should I enter?

Enter the design pressure and the design suction for the panel zone. The calculator uses the larger magnitude for the tension check, which typically reflects suction governing façade fixings.

2) Should I use areal weight or total mass?

Use areal weight when panel weight is uniform and known per square meter. Use total mass when you have a verified panel weight including attachments, brackets, or reinforcement.

3) What does the edge factor represent?

It increases edge fixing demand compared to field fixings to reflect higher perimeter effects. Choose a value that matches your façade zoning approach and detailing assumptions.

4) Why is there a material factor γm?

γm reduces stated fastener capacity to a design resistance. It helps account for variability, installation tolerances, and uncertainty in material performance and testing applicability.

5) What if the check fails even at tight spacing?

Increase fastener capacity, improve substrate strength, add rails or brackets to change load paths, reduce panel size, or revisit design pressures with a qualified façade engineer.

6) Does this include bending or pull-through of panels?

No. It focuses on fixing tension and shear distribution. Panel bending, pull-through, bracket flexure, and rail behavior should be checked separately using appropriate standards and details.

7) Can I use this for different substrates?

Yes, if your allowable capacities reflect the actual substrate and anchor type. Always base capacities on testing or validated manufacturer data for the exact base material condition.