Is dead load the same as total structural load on purlins?

No. Total structural load includes dead load (permanent weight), live load (typically 0.75 kN/m² per IS 875 Part 2), and wind load (IS 875 Part 3). Dead load is one component. A structural engineer combines all three using IS 800 load combinations.

Roof Dead Load Calculator

Q: How does insulation affect roof dead load?

Insulation adds its own weight to roof dead load. Glass wool 50 mm adds approximately 1.5 kg/m², PUF panels add around 4 kg/m². Always include insulation weight when sizing purlins.

Calculate sheet weight per m², insulation load, and total roof dead load for structural design — GI, aluminium, and galvalume sheets.

Sheet Profile GC Corrugated is the most common profile for sheds and warehouses.

Material GI has density 7850 kg/m³. Aluminium is 2700 kg/m³ — significantly lighter.

Sheet Thickness 0.47 mm is the standard commercial thickness for most shed and factory roofs.

Roof Area (sq metres) Enter the total sloped roof area in square metres. For gable roofs, include both slopes.

Insulation Insulation adds to the dead load that your structure must support.

How to Use This Calculator

Select sheet profile — choose the corrugation type that matches your roofing sheet.
Select material — GI, aluminium, or galvalume. Each has a different density that directly affects weight.
Choose thickness — thicker sheets are heavier. Standard commercial grade is 0.47 mm.
Enter roof area — total sloped area in square metres. For gable roofs, add both slopes together.
Select insulation — if you are using insulation under the sheet, select it here to include that load.
Click Calculate — the tool gives you sheet weight per m², insulation load per m², total dead load per m², and total roof weight in kg.

What Is Dead Load?

Dead load is the permanent static weight that a roof structure must carry — the weight of the sheets, insulation, fasteners, and any fixed fittings. Structural engineers use dead load (along with live load and wind load) to size purlins, rafters, and columns. IS 875 Part 1 covers imposed dead loads for Indian buildings. Knowing your roof dead load helps avoid under-designed purlins that deflect or fail over time.

Typical Roof Dead Load Values — IS 875 Part 1 Reference

Roof Component	Typical Dead Load (kg/m²)	Notes
GI sheet 0.47 mm (GC Corrugated)	3.69	Steel density 7850 kg/m³
GI sheet 0.63 mm	4.95	Heavy duty / industrial
Aluminium sheet 0.47 mm	1.27	Density 2700 kg/m³ — ~65% lighter than GI
Galvalume 0.47 mm	3.67	Density 7800 kg/m³
Glass wool insulation 50 mm	1.5	Add to sheet weight for total dead load
Glass wool insulation 75 mm	2.2	Higher thermal performance
PUF panel 50 mm	4.0	Rigid insulation — higher load than glass wool
Thermocol / EPS 50 mm	1.0	Lightest insulation option
Fasteners (self-drilling screws)	0.1 – 0.2	Usually negligible in dead load calculation

Values are based on IS 875 Part 1 (Dead Loads) and manufacturer published data. Use for estimation only — consult a structural engineer for project-specific design.

Frequently Asked Questions

What is the dead load of a 0.47 mm GI sheet?

A 0.47 mm GI sheet has a dead load of approximately 3.69 kg/m². This is calculated as (0.47 ÷ 1000) × 7850 kg/m³ = 3.69 kg/m². For a 100 m² roof with no insulation, total sheet weight is 369 kg.

Why is aluminium roof sheet so much lighter than GI?

Aluminium has a density of 2700 kg/m³ versus 7850 kg/m³ for steel — roughly one-third the weight. A 0.47 mm aluminium sheet weighs about 1.27 kg/m² compared to 3.69 kg/m² for GI. This reduced dead load can allow lighter purlin and column sections, lowering structural cost.

How does insulation affect dead load?

Insulation adds its own weight to the roof dead load. Glass wool 50 mm adds approximately 1.5 kg/m², PUF panels add around 4 kg/m². Always include insulation weight when sizing purlins — especially for PUF sandwich panel roofs where combined dead load can exceed 8–9 kg/m².

Is dead load the same as the total structural load on purlins?

No. Total structural load includes dead load (permanent weight), live load (maintenance personnel, temporary equipment — typically 0.75 kN/m² per IS 875 Part 2), and wind load (IS 875 Part 3, varies by zone). Dead load is just one component. A structural engineer will combine all three using the appropriate load combinations from IS 800.

Which IS standard covers dead loads for roof sheets?

IS 875 Part 1 (Code of Practice for Design Loads for Buildings and Structures — Dead Loads) covers unit weights of construction materials used in India. For steel roofing sheets, the standard gives a unit weight of 78.5 kN/m³ (7850 kg/m³) for steel. Always verify with your structural engineer as material densities can vary slightly between grades.