Norsound NOR625 Aluminium Door Threshold - 75mm wide

Norsound NOR625 Aluminium Door Threshold | 75mm Wide | T6060 Aluminium | 75 × 4.9mm

The NOR625 is a low-profile aluminium threshold plate from the Norsound 600 range, designed to provide a flat, level, and durable surface at the door sill for use with Norsound door bottom seals. A threshold plate serves two functions in an acoustic doorset assembly: it provides a consistent engagement surface for the door bottom seal to close against, and it bridges the gap between the floor finish and the door frame base, eliminating the uneven or recessed sill conditions that prevent door bottom seals from achieving full contact across the width of the door. Without a threshold, variations in floor level, floor finish thickness, or sill geometry can prevent the door bottom seal from sealing consistently, reducing the acoustic performance of the assembly regardless of the seal specification.

The NOR625 is manufactured from T6060 grade aluminium and anodised to AA10 standard in satin silver. The profile is 75mm wide × 4.9mm high — a wider section than the NOR620, providing a larger engagement platform suited to wider door bottom seal profiles or installations where greater sill coverage is required. The low-profile 4.9mm height minimises trip hazard and complies with Approved Document M requirements for accessibility at doorways. Available in standard lengths of 1000mm and 2100mm. Screw-fixed to the floor or sill substrate.

Applications

• Engagement surface for Norsound door bottom seals — install at the door sill to provide a flat, level surface for the NOR815, NOR820, or NOR855 door bottom seal to engage against. The 75mm width provides a wider engagement platform than the NOR620, accommodating larger seal footprints or installations where the door bottom seal travel arc requires a wider threshold coverage. The threshold ensures the seal makes consistent contact across the full width of the door on every close.
• Floor finish transition at door sills — the 4.9mm profile height bridges minor level differences between floor finishes on either side of the door, providing a smooth transition that does not create a trip hazard. Complies with Approved Document M requirements for threshold height at accessible doorways.
• Retrofit installation on existing doorsets — screw-fixed directly to the floor or sill substrate, the NOR625 can be installed on existing doorsets without modification to the door frame or leaf. Cut to length on site if required.

Product Benefits

• 75mm width — wider engagement platform than NOR620. The 75mm width provides a larger sill coverage area than the 60mm NOR620, making it the appropriate choice where the door bottom seal footprint is wider, where the door swing arc requires greater threshold coverage, or where the sill condition requires a wider bridging plate.
• Consistent seal engagement surface — improves door bottom seal performance. The flat, level aluminium surface provides a consistent engagement point for Norsound door bottom seals across the full width of the door. Variations in floor finish, screed level, or sill geometry beneath the door are bridged by the threshold, ensuring the seal closes against a predictable surface on every cycle.
• T6060 aluminium — anodised AA10 finish. T6060 grade aluminium provides high strength and corrosion resistance in a threshold application subject to foot traffic and cleaning. The AA10 anodised finish in satin silver is durable, low-maintenance, and compatible with standard commercial and residential doorset aesthetics.
• Low-profile 75 × 4.9mm section — Approved Document M compliant. The 4.9mm profile height minimises the trip hazard at the threshold and complies with Approved Document M requirements for accessibility at doorways.
• Two standard lengths — 1000mm and 2100mm. Available in 1000mm and 2100mm lengths to suit standard door widths. Cut to length on site if required.

Installation

Measure the door opening width and select the appropriate length. Cut to length on site if required, ensuring the threshold spans the full width of the door opening.

Position the NOR625 centrally across the door sill, aligned with the door leaf. Mark and drill fixing holes through the threshold into the floor or sill substrate. Countersink fixings flush with the threshold surface. Check that the threshold surface is level across its full width. Install the door bottom seal (NOR815, NOR820, or NOR855) and verify that the seal engages the threshold surface consistently on closing.

The Technical Details