Acoustic Flooring Calculator — Underlay, Mat & Adhesive

This calculator works out acoustic flooring material quantities based on your room area, floor type and Building Regulations requirement.

What we calculate

• Underlay: Roll count based on room area plus a cutting/wastage allowance
• Subfloor-bonding adhesive: The thin adhesive that bonds the underlay or decoupling mat to the subfloor (kg per m²). This is not the tile-fixing adhesive — floor-tile adhesive is roughly 4–7 kg/m² and is ordered separately from the tile manufacturer’s datasheet
• Acoustic mat: A decoupling mat for Part E and BREEAM compliance — added as a separate layer
• Perimeter strip: Resilient foam strip around room edges (Part E flanking control)
• Joining tape: Tape for the butt-joints between underlay sheets

Cutting and wastage allowance

Acoustic and laminate underlay is laid butt-jointed — each sheet closely abutted to the next and the seams taped. It must not be overlapped: an overlap creates a raised ridge that telegraphs through the floor finish and locally defeats the acoustic layer (only damp-proof membranes are overlapped). The allowance the calculator adds — default 10% — therefore covers offcuts and cutting waste, not overlap. Increase it for rooms with lots of cuts (bays, alcoves, diagonal runs).

Perimeter strip

The resilient perimeter strip is estimated from the room perimeter. If you only enter a floor area, a square room is assumed — the smallest possible perimeter for that area, so long, narrow rooms are under-estimated. Enter the room length and width in the advanced options for an accurate 2 × (length + width) perimeter. Roll coverages shown are typical UK values (e.g. laminate underlay 1 m × 15 m = 15 m²); decoupling-mat rolls vary widely (about 6.25–30 m²) — always check your product’s actual coverage.