Flat Roof Material Calculator
Flat Roof Material Calculator
Estimating materials for a flat roof project? This calculator helps you plan your felt, EPDM, insulation, decking, and adhesive quantities with ease.
Technical Guidance
- UK: Most felt/EPDM rolls cover 8–12m² — always overlap seams
- USA: Common EPDM roll = 10x20ft or 15x25ft — plan overlaps
- Flat roofs require good drainage — include falls and upstand coverage
Pro Tips
- Add 10% extra membrane for corners, folds, and detailing
- Use vapour barriers under insulation for warm decks
- Include adhesive, trims, and upstand flashings in your material list
FAQs
- How much felt for 30m²? → Allow 33–35m² total including overlap
- Can I use this for warm and cold roof? → Yes, just adjust insulation type accordingly
