Flat Roof Membrane Calculator — m to rolls, adhesive, cost
How to use this calculator
Enter flat roof dimensions in meters and centimeters — length × width or direct area. Choose membrane type (EPDM, TPO, PVC, or modified bitumen), roll width (1.5 m or 3 m), and seam overlap. Results include rolls, adhesive, edge trim, and optional insulation boards with cost estimate.
Membrane types — EPDM (rubber), TPO (heat-welded), PVC (chemical resistant), Modified bitumen (torch/cold-applied).
Overlap — 75–150 mm depending on membrane type. Select your currency for cost estimates.
Saved Calculations
| Time | Type | Area m² | Rolls | Adhesive | Edge | Total |
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How to Calculate Flat Roof Membrane (Metric)
This calculator estimates membrane rolls, adhesive, edge trim, fasteners, and optional insulation boards for flat or low-slope roofs. Supports EPDM, TPO, PVC, and modified bitumen membranes with metric dimensions. Roll widths of 1.5 m and 3.0 m with lengths of 15–25 m are available.
Formulas
Effective coverage = (roll width − overlap) × roll length. Rolls = ceil(area × (1 + waste%) / effective coverage). Adhesive = area / 10 m² per litre for fully adhered, in 20 L pails. Fasteners ≈ 10 per m² for mechanically attached systems.
FAQ
What overlap for TPO/PVC? Heat-welded seams typically require 75–100 mm overlap. Modified bitumen uses 100–150 mm. Always follow manufacturer specifications per EN 13956.
Do I need insulation? EN standards require thermal insulation below the membrane. Typical boards are 1.2 × 2.4 m polyiso or EPS.
